# U.S. Army U.S. Air Force                                              Afman 32-1072 Water-Well Drilling Operations

## Edition December 2008

URGENT CHANGE/ERRATUM RECORD
| NUMBER                    | DATE    | ENTERED BY    |
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| PRIMARY REVIEW AUTHORITY: |         |               |
| COMMANDER, FIRST NAVAL    |         |               |
| CONSTRUCTION DIVISION     |         |               |
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## Department Of The Navy Office Of The Chief Of Naval Operations, Headquarters, U.S. Army, And Headquarters, U.S. Air Force

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|     | PUBLICATION NOTICE    | ROUTING    |
|-----|-----------------------|------------|

1. NTRP 4-04.2.13/FM 3-34.469/AFMAN 32-1072 (DEC 2008), WATER-WELL
DRILLING OPERATIONS, is available in the Navy Warfare Library. It is effective upon
receipt.
2. This publication provides general information for engineer personnel responsible for
planning, designing, and drilling wells, focuses on techniques and procedures for installing wells, and includes expedient methods for digging shallow water wells, such as hand-dug wells.

_____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________

3. Summary. Military personnel assigned to well drilling teams must have a basic
understanding of groundwater principles and well drilling mechanics and hydraulics to
successfully install wells. A well driller enhances his skills primarily from experience in solving problems, overcoming obstacles in the field, and learning from failures. This publication reviews common experiences well drillers encounter in the field, including well installation and completion

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Navy Warfare Library publications must be made readily available to all users and other interested personnel within the U.S. Navy.
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## Appendix E - Forms

E.1
WELL DRILLING FORMS........E-1

## Preface

The provisions of this publication are the subject of international standardization agreement (STANAG) 2885
ENGR (Edition 4), *Emergency Supply of Water in War*. Throughout this publication, references to other publications imply the effective edition. Report administrative discrepancies by letter, message, or e-mail to: COMMANDER NAVY WARFARE DEVELOPMENT COMMAND ATTN: N5
686 CUSHING ROAD NEWPORT RI 02841-1207 fleetpubs@nwdc.navy.mil

## Ordering Data

Order printed copies of a publication using the Print on Demand (POD) system. A command may requisition a publication using standard military requisitioning and issue procedures (MILSTRIP) or the Naval Supply Systems Command (NAVSUP) website called the Naval Logistics Library (NLL) (https://nll.ahf.nmci.navy.mil).

An approved requisition is forwarded to the specific Document Automation and Production Service (DAPS) site at which the publication's electronic file is officially stored. Currently, two copies are printed at no cost to the requester.

## Change Recommendations

Procedures for recommending changes are provided below.

## Web-Based Change Recommendations

Recommended changes to this publication may be submitted to the Navy Warfare Development Doctrine Discussion Group, accessible through the Navy Warfare Development Command website at: http://www.nwdc.navy.smil.mil/.

## Urgent Change Recommendations

When items for changes are considered urgent (as described in Paragraph 3.4.2), send this information by message to the Primary Review Authority, info NWDC. Clearly identify and justify both the proposed change and its urgency. Information addressees should comment as appropriate. See accompanying sample for urgent change recommendation format on page 18.

## Routine Change Recommendations

Submit routine recommended changes to this publication at any time by using the accompanying routine change recommendation letter format on page 19 and mailing it to the address below, or posting the recommendation on the NWDC Doctrine Discussion Group site.

COMMANDER NAVY WARFARE DEVELOPMENT COMMAND DOCTRINE DIRECTOR (N5) 686 CUSHING ROAD NEWPORT RI 02841-1207 COMMANDER US ARMY TRAINING AND DOCTRINE COMMAND ATTN: AFTC-RD FORT MONROE, VA 23651-5000 DSN 680-3951 COMM (757) 788-3951 E-MAIL:  DOCTRINE@MONROE.ARMY.MIL HQ AFDC/DJ 155 NORTH TWINING STREET
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CHANGE SYMBOLS
Revised text in changes is indicated by a black vertical line in either margin of the page, like the one printed next to this paragraph. The change symbol indicates added or restated information. A change symbol in the margin adjacent to the chapter number and title indicates a new or completely revised chapter.

## Warnings, Cautions, And Notes

The following definitions apply to warnings, cautions, and notes used in this manual:

 An operating procedure, practice, or condition that may result in injury or death if not carefully observed or followed.
An operating procedure, practice, or condition that may result in damage to equipment
if not carefully observed or followed.
An operating procedure, practice, or condition that requires emphasis.

## Wording

Word usage and intended meaning throughout this publication is as follows: "Shall" indicates the application of a procedure is mandatory. "Should" indicates the application of a procedure is recommended. "May" and "need not" indicate the application of a procedure is optional. "Will" indicates future time. It never indicates any degree of requirement for application of a procedure.

## Acknowledgments

Acknowledgment is gratefully made to the organizations listed below for permitting the use of copyrighted material in the preparation of this manual. Baroid Drilling Fluids, Inc. Houston, Texas Ingersoll-Rand Company *The Button Bit vs. The Rock*
Johnson Filtration Systems, Inc. *Ground Water and Wells,* 3rd Edition


FM ORIGINATOR TO *(Primary Review Authority)*//JJJ// INFO COMNAVWARDEVCOM NEWPORT RI//N5//
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## Chapter 1 Introduction 1.1 Field Water Supply

Maintaining a constant supply of water is critical to sustaining the force. Beyond military consumption, a water supply is critical for chemical, biological, radiological, or nuclear (CBRN) decontamination, sanitation, construction, medical operations, and equipment maintenance. The quantity and quality of water required depends upon climatic conditions, terrain, and the type of operation conducted.
In an operational area (OA), the tactical or installation commander provides water support requirements to general engineer (GE) units under the combat service support (CSS) element. The CSS element is tasked in turn to provide water. Requests for well drilling support go through operational channels to higher headquarters
(HHQ). Tactical and logistical personnel plan and coordinate water support functions. They ensure that sufficient water production and distribution assets are available to continuously support the forces in the OA. Planners should consider the following items when locating well sites:

1. Tactical situation 2. Geographical OA 3. Impact of well on other wells utilizing the same aquifer 4. Location of existing water sources 5. Size of the force being supported 6. Planned force deployment rates 7. Dispersion of forces in a geographic area
8. Water consumption rates and anticipated well capacity 9. Availability of transportation to move well drilling equipment and well-completion materials
10. Logistical support and main supply routes 11. Availability of assets for water distribution 12. Time required for drilling and preparing a well for production 13. Environment impact or contamination 14. Water purification assets.
Groundwater sources are normally used to supplement surface-water sources. GE support in the form of well drilling by engineers is provided to the water collection and distribution process. Specific considerations necessitating well drilling are:

1. When surface sources of water are not available in enough quantity or quality to support the force. This is
likely to occur in arid terrain where the quantity of water required is high and surface sources are low. In arid environments, exploring and using groundwater can reduce the need to transport water to a desired
location.
2. If the distribution system is insufficient to support the force, haul distances may be significantly reduced
by a well drilled close to the consumer.
3. CBRN or other type of contamination is expected that would render surface sources unusable.
4. The mission is part of a humanitarian and civic assistance (HCA) and/or foreign humanitarian assistance
(FHA) mission. A major portion of the world's population lacks a readily available source of potable
water. Providing a potable source by conducting well drilling operations (OPS) may be the decisive operation in stability and/or reconstruction operations and a critical part of the overall information
operations campaign.
Globally the demand for safe drinking water is not being met.  According to the United Nations Environmental Programme report Our Planet, the uneven distribution and increasing demand creates regions of water stress. Currently 40 percent of the world's population, about one billion people, is under water stress and will increase to 67 percent by 2025. Another billion people live in regions with adequate water supply but cannot afford water.

"Freshwater," *Our Planet,* 2003

## 1.2 Water Detection

1. *Responsibilities.*  In an undeveloped or a developed OA, terrain analysts, ground-survey teams, and well
drilling teams identify surface-water and groundwater sources. Water detection for all Service water-well drilling teams is typically achieved either through contract or by the Army's Water Detection Response Team (WDRT). Refer to Appendix D for details on the WDRT. Engineer ground-survey teams determine whether a groundwater source is adequate and accessible for development.
2. *Procedures.* Analysts use surface water, groundwater, and existing-water-facilities overlays from the
worldwide Department of Defense (DOD) Water Resources Database (WRDB) maintained by the Army. Refer to Appendix D for details on the WDRB. Surface- and existing-water-facilities water sources are identified primarily from maps and visual inspection. Groundwater sources are identified by analyzing
information from groundwater-resources overlays, maps, aerial imagery, terrain studies, hydrologic and geologic data, well drilling logs, and local-national sources. Two methods of locating groundwater are:
- Method 1. WDRTs or contractors, equipped with special devices that use geophysical techniques
(electrical resistivity and seismic refraction), may be deployed to locate groundwater.
- Method 2. Well drilling teams may drill exploratory or test wells to detect groundwater. Georesistivity
testing is an option if the resources are available in theatre and time or funding allows.
The second method is accurate but time consuming. Teams should use this method only if all other waterdetection methods are unsuccessful or are not available. The methods used for detecting water depend on the urgency for finding groundwater and the resources available. Speed and accuracy are essential for locating water in any OA.

3. *Equipment.* The WDRT's water-detection equipment is deployable by air, sea, or ground transport into a
developed or undeveloped OA.

## 1.3 Well Drilling

Wells provide water to the deployed forces in an undeveloped OA, to the forward deployed units in a developed theater, and to the forces that occupy permanent or semipermanent installations in a developed OA. Wells are located and drilled in secure areas in an installation or in the OA by Service water-well drilling teams as discussed in Paragraph 1.4.

1. *Forward Deployed Forces in a Developed OA.* Well drilling OPS support forward deployed forces and
force buildup in a developed OA. Groundwater sources supplement, but do not replace, surface water
sources. Well drilling teams conduct well drilling OPS during all phases of an operation. Rapid movement of the well drilling team into the OA is not essential. Teams with organic equipment arrive at the OA
primarily by sea or ground from prepositioned locations. The teams may depend on supported units for logistical and administrative support. Transportation support is also usually required for movement of well
drilling equipment and components.
2. *Permanent or Semipermanent Fixed Installation Forces in a Developed OA.* These installations are
located in built-up or rural areas where water sources may be available. Groundwater sources supplement
existing water sources to meet installation water requirements. The wells are permanent. The facilities engineer manages all water utilities on an installation.
3. *Combat Zone.* The OPS Officer of the supporting unit the well drilling team is attached to coordinate
OPS with the supported unit. When the well drilling team completes a well, they turn it, all installed
equipment and technical specifications over to the OPS Officer. The OPS Officer then turns the operation
over to the supported unit. Unless other arrangements are made in advance, the supported unit is responsible for:
a. Drawing water from the stave tank to purify, treat, store, and distribute water.
b. Operating all equipment at the well site, to include the well pump and generator. c. Maintaining all equipment except the well pump and screens.
Any well repair or maintenance that exceeds the capability of the supported unit must be coordinated through the staff engineer that supports the OA.

4. *Communications Zone (commz).* The well drilling team's OPS section coordinates OPS with supported
units, civil affairs personnel, or host nation (HN) support (HNS) units as required. When the well-drilling team completes a well, they turn over the operating well, all installed equipment, and the technical
specifications to the OPS Officer, who then turns the operation over to the facilities engineer. The facilities engineer coordinates with supply planners, civil-affairs personnel, or the HN regarding well OPS and maintenance. HNS is used whenever possible to support well drilling OPS.

## 1.4 Well Drilling Teams

To accomplish the well drilling mission, well drilling teams (with organic equipment) are deployed to the OA by air, sea, or ground. Each team has a truck- or semitrailer-mounted drilling machine. They use these machines to reach deep aquifers and develop wells. Teams also have well-completion kits. Kits include the casing, screen, pumps and generators, and other necessary equipment needed to provide an aquifer-to-storage-tank capability.

The teams may depend on supported units for logistical and administrative support. Transportation support is also usually required to move well drilling equipment and components.

1. All Service well drilling teams are able to do the following, at a minimum:
 a. Disassemble, transport, and reassemble the drilling rig.
b. Set up the well drilling rig and support equipment.
 c. Drill up to a 1,500-foot, 15-inch diameter well (Army equipment is 600 feet (ft) adaptable to 1,500 ft
with additional air compressor set up).
d. Drill with mud, air, and foam circulation.
 e. Drill with a down-the-hole hammer.
f. Drill in sand, soil, clay, rock, or other geological formations.
g. Perform operator's service checks and maintenance. h. Develop the well for connecting and interfacing with storage facilities and water-distribution systems.
2. Refer to the following appendices for information on Service-specific well drilling teams and OPS:
 a. *Army*. See Appendix A. b. *Navy.* See Appendix B.
 c. *Air Force.* See Appendix C.

## Chapter 2 Groundwater 2.1 Fundamentals

To locate and evaluate water sources, team leaders must know about the earth's topography and geologic formations. Surface sources of water, such as streams, lakes, and springs, are easy to find. Reconnaissance personnel are responsible for locating surface-water sources and for providing adequate water supplies to troops in the field. Groundwater sources often require more time to locate. Geologic principles can help engineers locate groundwater supplies and eliminate areas where no large groundwater supplies are present. About 97 percent of the earth's fresh water (not counting the fresh water frozen in the polar ice caps and glaciers) is located underground. Most of the groundwater tapped by water wells is derived from precipitation on the earth's surface.

## 2.2 Hydrologic Cycle

The constant movement of water above, on, and below the earth's surface is the hydrologic cycle (see Figure 2-1). The concept of the hydrologic cycle is that precipitation returns again to the atmosphere by evaporation and transpiration. Understanding this cycle is basic to finding groundwater. Three-fourths of the earth's surface is covered by ocean water. Direct radiation from the sun causes water at the surface of the oceans to change from a liquid to a vapor (evaporation). Water vapor rises in the atmosphere and can accumulate as clouds. When the clouds accumulate enough moisture and conditions are right, the water is released in the form of rain, sleet, hail, or snow (precipitation).

1. *Recharge and Discharge.* Precipitation on land surfaces may be stored on the surface. It also flows along
the surface (runoff) or seeps into the ground (infiltration). Surface storage is in lakes, ponds, rivers, and streams and is snow and ice. Polar ice caps and glaciers store 85 percent of the earth's fresh water. Runoff provides the main source of water for streams and rivers. Water infiltrating into the soil is the major source of groundwater. Water that seeps into the ground *recharges* groundwater resources.
  As groundwater moves from the recharge area, it may *discharge* back to the surface. Groundwater flows
from recharge areas to discharge areas where the water is discharged to lakes, rivers, springs, and oceans (see Figure 2-2). Another form of discharge is the consumption of water by plants and animals. Plants draw large quantities of water from the soil and return this water to the atmosphere (transpiration). Man
also causes water discharge for consumption.
2. *Water Storage*. Water wells are constructed to produce water supplies from groundwater reserves.
Developing a groundwater supply has many advantages over using surface water. Groundwater is more abundant than surface water, is often cleaner, requires less treatment, and may be easier to protect than surface-water supplies. A water well is easy to seal from natural contamination and to protect from clandestine contamination. Groundwater supply remains unaffected by short-term drought unless it relies
directly on surface sources.

## 2.3 Groundwater Occurrence

The hydrologic cycle exists on global and local levels. By understanding the local hydrologic cycle, it is possible to predict the directions and rates of groundwater flow, to identify groundwater resources, and to select development areas. An area drained by a stream or river is a drainage basin. For example, the Mississippi River Basin includes most of the area between the Rocky and Appalachian Mountains (see Figure 2-3). Major river basins are subdivided into smaller basins. The Missouri and Ohio River Basins are regional subdivisions of the Mississippi River Basin. These subdivisions can also be divided into local drainage basins (hydrographic basins)
for each tributary (see Figure 2-4). The boundaries of hydrographic basins are usually represented by mountains or hills, which restrict the flow of water, and by low areas where the water is discharged out of the basin.

The depth to groundwater may range from very near the surface to more than 1,000 ft. In most arid areas, the shallowest groundwater sources occur in recharge and discharge areas. Precipitation over mountainous areas results in a groundwater recharge at the base of the mountains into alluvial valleys. Precipitation over a mountainous area results in higher runoff and lower groundwater recharge ratios on the slopes of mountainous terrain. Even though groundwater may be shallow in these areas, the rough terrain and the rocks make mountainous areas difficult sites for water wells. Although mountainous areas are presumed to be recharge areas, military engineers do not normally drill tactical water-supply wells on mountain sides.

## 2.4 Geological Setting

The ability of soils and rocks to hold and transmit water varies, and the depth to groundwater varies in different geological settings. Physical properties of soils and rocks, such as degree of consolidation, cementation, and hardness, determine drilling methods and the potential for groundwater production. When drilling, consolidated rock is harder to penetrate but is more stable than unconsolidated rock. Well drillers usually use a down-hole air hammer on consolidated rock with no well casing for support. Drillers must support holes in unconsolidated rock to avoid cave-ins. Wells in unconsolidated rock frequently yield more water at a shallower depth than wells in consolidated rock. The list below describes the degree of consolidation in more detail:

1. *Unconsolidated Deposits*. Unconsolidated deposits:
a. Cover the majority of the earth's surface.
b. Range in thickness from a few inches to several thousand ft.
c. Can underlie consolidated rocks.
d. Consist of weathered rock particles of varying materials and sizes.
e. Include clays, silts, sand, and gravel.
f. May include salt deposits and fragments of shells of marine organisms.
2. *Consolidated Deposits (Rock).* These rocks consist of mineral particles of different sizes and shapes. Heat
and pressure or a chemical reaction has formed the rocks into a solid mass (often called bedrock).
Geologists classify consolidated deposits into the following three categories, depending on origin:
a. *Igneous*. These rocks form when hot molten material (magma) cools and solidifies either inside the
earth's crust or on the earth's surface (lava). Basalt and granite are two common igneous rocks that military well drillers encounter.
b. *Sedimentary*. These rocks are composed of sediments that are converted to rock through compaction,
cementation, or crystallization. Sedimentary rocks cover about 75 percent of the earth's surface. Shale,
sandstone, and limestone comprise over 95 percent of these rocks.
c. *Metamorphic*. These rocks are igneous, sedimentary, or preexisting metamorphic rocks that undergo
further transformation by temperature, pressure, or chemical changes. The transformation usually
occurs very deep in the earth's crust; Schist and gneiss are common metamorphic rocks.

## 2.5 Groundwater Hydraulics

The list below describes basic groundwater hydraulic principles:

1. *Porosity.* Soil and rock are composed of solids and voids (pores). Groundwater can fill up and flow
through pores. Pores formed at the same time as the rock such as in sand, gravel, and lava tubes in basalt, are called primary openings. Pores formed after the rock was formed are called secondary openings. Examples are fractures in massive igneous rocks like granite and the caves and caverns in limestone. The pore sizes vary and may or may not be filled with water. The ratio of volume of the pore space to the total volume of the soil or rock is called porosity. Porosity is normally expressed as a
percentage (see Figure 2-5). Figure 2-6 shows primary and secondary openings.
2. *Permeability.* The property of permeability is related to porosity. In qualitative terms, permeability is
expressed as the capacity of a porous rock or soil to transmit a fluid. Large interconnected pore openings
are associated with high permeability, while very small unconnected pore openings are associated with low permeability. Sand and gravel with large interconnected pore openings have high porosity and permeability. Clay tends to have high porosity, but the very small openings tend to inhibit the passage of water. Therefore, clay displays low permeability.

| Material                      | Primary Openings    | Secondary Openings    |
|-------------------------------|---------------------|-----------------------|
|                               |                     |                       |
|                               |                     |                       |
| 48                            |                     |                       |
| 26                            |                     |                       |
| Equal-size spheres (marbles): |                     |                       |
| -                             |                     |                       |
| Loosest packing               |                     |                       |
| -                             |                     |                       |
| Tightest packing              |                     |                       |
| Soil                          | 55                  |                       |
| Clay                          | 50                  |                       |
| Sand                          | 25                  |                       |
| Gravel                        | 20                  |                       |
| Limestone                     | 10                  | 10                    |
| Sandstone (semiconsolidated)  | 10                  | 1                     |
| Granite                       |                     | 0.1                   |
| Basalt (young)                | 10                  | 1                     |

Hydraulic conductivity is a measurement of the capacity of rock or soil to transmit water. The higher the hydraulic conductivity, the faster the water will flow at a given pressure (see Figure 2-7). Hydraulic conductivity is related to the size and spacing of particles or grains in soils or to the number and size of fractures in rocks (see Figure 2-8). The hydraulic conductivity of rocks and soil is measured by field or laboratory tests. Findings are recorded as volume of water flowing per unit area per unit of time and expressed as foot per day or centimeter per second (cps).

3. *Specific Yield and Retention*. Figure 2-9 shows specific yield and retention percentages. Only a portion of
the water stored in pores can be pumped out of a well. Specific retention (Sr) is the water that cannot be
pumped out of a well and is left as a film on the rock surfaces. Specific yield (Sy) is the water that can
potentially be pumped from a well (see Figure 2-10). The Sr and Sy percentages compared to porosity
indicate how much water is developable from a rock formation.

| Material                     |   Porosity  |   Specific Yield  |   Specific  |
|------------------------------|-------------|-------------------|-------------|
| Retention                    |             |                   |             |
| Soil                         |        55   |             40    |        15   |
| Clay                         |        50   |              2    |        48   |
| Sand                         |        25   |             22    |         3   |
| Gravel                       |        20   |             19    |         1   |
| Limestone                    |        20   |             18    |         2   |
| Sandstone (semiconsolidated) |        11   |              6    |         5   |
| Granite                      |         0.3 |              0.09 |         0.1 |
| Basalt (young)               |        11   |              8    |         3   |

4. *Transmissivity*. Although hydraulic conductivity measures the relative flow of water through a subsurface
material, the results may not be an accurate measurement of the yield that is obtainable from the material.
The inaccuracy exists because hydraulic conductivity does not account for the thickness of the waterbearing unit (aquifer). For example, a well in a 100-ft-thick aquifer will produce more than a well in a 9- ft-thick aquifer provided both aquifers have the same permeability. Hydraulic conductivity is the watertransmitting capacity of a unit of an aquifer (see Figure 2-11, A). Transmissivity is the water-transmitting
capacity of a unit prism (the saturated thickness) of the aquifer and usually is expressed in units of gallons per day per foot of aquifer width (see Figure 2-11, B). Wells in high transmissivity areas will produce high well yields. Wells in low transmissivity areas will produce low well yields.
5. *Yield and Drawdown.* Yield is the volume of water discharged from the well per unit of time when water is
being pumped or is flowing freely. Yield is commonly measured in units of gallons per minute (gpm) and
  gallons per hour (gph) for small yields or in cubic feet per second (cfs) for large yields. Yield is a measure
of how readily an aquifer gives up its supply of groundwater. Drawdown is a measure of how much the
water level near the well is lowered when the well is pumped. Drawdown is the difference (in feet) between the static water level and the water level when pumping (see Figure 2-12). It occurs in a cone shape radiating outward from well which is important for locating secondary wells. See Chapter 8 for methods of measuring yield and drawdown.
6. *Hydraulic Gradient.* Darcy's Law describes the flow of groundwater and is applied to evaluate aquifer
and aquifer material hydraulic characteristics. The hydraulic gradient is the change in head (water elevation) with distance. The hydraulic gradient determines the direction of groundwater flow.
  To calculate the hydraulic gradient, use the following formula:
L h ) (h i 1  2 =
where: i   = *hydraulic gradient, dimensionless (slope)* h = hydraulic head, in ft.

L = horizontal distance from h1 to h2, in ft (*see Figure 2-13*)

  Darcy's experiments show that the flow of water through a column of saturated sand is proportional to the
difference in the hydraulic head at the ends of the column. Darcy's Law is still used as the basic principle
that describes the flow of groundwater and is expressed as follows:
Q = KiA where: Q = quantity of water discharged per unit time, in cfs K = hydraulic conductivity (constant factor) i = hydraulic gradient, in ft A = cross-sectional area, in square ft

7. *Aquifer Tests.* Groundwater aquifer performance and well efficiency are tested by placing boreholes
through the aquifer. Testing and recording the yield and the drawdown can provide useful information to
select the best pumping equipment and well screens for the actual well. Measurements of drawdown in observation wells (near the pumping well) and accurate pumping rates of the actual well will provide
useful information on the hydraulic characteristics of the aquifer.
  Aquifer tests provide values of hydraulic conductivity and transmissivity that better represent the actual
aquifer than laboratory permeability tests conducted on small intact samples. The much greater volume of aquifer material tested in a field aquifer test takes into account secondary porosity in fractures and connected voids as well as the primary porosity of the materials. Field aquifer tests may also reveal the presence of boundary zones, which are zones of greater or lesser permeability or recharge zones that define the limits of the aquifer. Aquifer test data is useful in determining well yield (discharge) for groundwater supply and in engineering projects requiring dewatering of excavation sites and subsurface excavation.

## 2.6 Aquifers

Saturated rock or soil units that have sufficient hydraulic conductivity to supply water for a well or spring are aquifers. Aquifers transmit water from recharge areas to discharge areas, such as springs, lakes, and rivers.

Typical aquifers are gravel, sand, sandstone, limestone, and fractured igneous and metamorphic rock. Those subsurface rock or soil units that do not transmit water readily and cannot be used as sources of water supplies are called aquicludes. Typical aquicludes are clay, shale, and unfractured igneous and metamorphic rock.

Aquicludes that exist between aquifers are confining beds; meaning that the water moves only within the aquifer.

The list below describes aquifer configurations in more detail:

1. *Unconfined.* These are aquifers that are partly filled with water, have fluctuating water levels, and can
receive direct recharge from percolating surface water. Wells drilled into an unconfined aquifer are called
water table wells (see Figure 2-14). Unfortunately, shallow, unconfined aquifers are subject to surface contamination such as farm land, industrial waste, and raw sewage.
2. *Confined.* These are aquifers that are completely filled with water and are overlaid by a confining bed.
The water level in a well supplied by a confined aquifer will stand at some height above the top of the aquifer. Water that flows out of the well is called a flowing artesian (see Figure 2-15). Water rises because
of the pressure that the overlying materials exert on the water and the height of the column of water driving the water through the interconnecting pores of the aquifer. The height of the column of water that is driving water through the aquifer is the head. The height that the water will rise to inside a tightly cased
artesian well is the potentiometric surface and represents the total head of the aquifer.
3. *Perched.* These aquifers lie above an unconfined aquifer and are separated from the surrounding
groundwater table by a confining layer (see Figure 2-16). These aquifers are formed by trapping infiltrating water above the confining layer and are limited in extent and development. In some arid environments, perched aquifers form sources of shallow and easily developed groundwater.
4. *Catchment.* These aquifers are formed where impervious rock underlies a zone of fractured rock or
alluvium that serves as a reservoir for infiltrated water (see Figure 2-17). A catchment is a special type of perched aquifer. Catchments cannot provide large quantities of water, but they may provide easily developed groundwater for small demands or temporary supplies for drilling OPS.

## 5. Material.

a. *Unconsolidated sediment*. Examples of sediment deposits and their sources are:
(1) Alluvium, which comes from running water. (2) Glacial drift, which comes from flowing ice.
(3) Sand dunes, which come from blowing winds.
  Sand and gravel deposits are the primary materials of unconsolidated aquifers. Alluvial deposits are
prevalent in river valleys in humid environments and in dry gullies in arid environments. In many desert areas, alluvial deposits may be the primary source of groundwater. These deposits may be unconfined, confined, or perched.
b. *Rock*. This aquifer is a mass of rock that can store and transmit groundwater.
(1) Limestones and dolomites. These are carbonate rocks that dissolve when carbon dioxide from the
atmosphere and groundwater mix to form carbonic acid. The acid dissolves and widens the fractures and bedding planes into larger rock openings. These openings may eventually develop into caves. Limestone with fractured zones develops solution channels. Caves can produce aquifers that yield appreciable quantities of groundwater (see Figure 2-18).
(2) Basalt. This may be an igneous rock which may be a productive water-bearing unit. The water
flows through openings that include lava tubes, shrinkage cracks, joints, and broken or brecciated
zones at the top of cooled lava flows (see Figure 2-19).
(3) Sandstone. This is consolidated or cemented sand. In unfractured sandstone, groundwater may
store in the pores between individual sand grains which is recoverable through pumping. Water in
sandstone may flow through bedding planes and joints.

## 2.7 Groundwater Exploration

In groundwater exploration, it is possible to predict the location of an unconfined aquifer within alluvial sediments. However, identifying these unconfined alluvial aquifers requires a detailed knowledge of sediments in the area. Usually, this information can only be obtained from existing water or oil well drilling records from the United States Army Corps of Engineers (USACE), Topographic Engineering Center (TEC), WDRT or from an exploratory drilling program. For development of water supplies in support of tactical OPS, the unconfined aquifer will be the preferable target zone. Deeper confined aquifers should be investigated if an unconfined aquifer cannot provide an adequate water supply or if the unconfined aquifer is nonpotable.

Rock aquifers should be considered for exploration only when unconsolidated aquifers are not present or are unable to provide a sufficient water supply. Identifying suitable well sites in rock aquifers is more difficult than in unconsolidated aquifers. Water development in rock aquifers is more time-consuming and costly and has a higher risk factor. However, in some areas, rock aquifers may be the only source of groundwater.

Indicators of groundwater resources are those conditions or characteristics that indicate the occurrence of groundwater. No indicator is 100 percent reliable for detecting groundwater, but the presence or absence of certain indicators aids detection possibilities. Indicators useful in identifying groundwater resources are called hydrogeologic indicators (see Figure 2-20). The list below describes different types of indicators in more detail:

1. *Reservoir Indicators.* These indicators are characteristics in soils, rocks, and landforms that define the
ability of the area to store and transmit groundwater, but do not directly indicate the presence of groundwater. One of the first steps in groundwater exploration is to identify and evaluate reservoir indicators.

| Reservoir Indicators         | Surface Indicators      | Boundary Indicators         |
|------------------------------|-------------------------|-----------------------------|
| Rock type and geometry       | Springs and seeps       | Location of recharge areas  |
| Stratigraphic                | Soil moisture           | Location of discharge areas |
| Degree of lithification      | Vegetation type         | Impermeable barriers        |
| Grain size                   | Vegetation density      | Semipermeable barriers      |
| Fracture density             | Wetlands                | Surface-water divides       |
| Dissolution potential        | Playas                  |                             |
| Cumulative structure density | Wells                   |                             |
| Drainage basin size          | Reservoirs              |                             |
| Drainage basin elevation and |                         |                             |
| relief                       |                         |                             |
| Crop irrigation              |                         |                             |
| Drainage pattern             | Salt encrustations      |                             |
| Drainage density             | Population distribution |                             |
| Landforms                    | Streams and rivers      |                             |
|                              | Snow-melt patterns      |                             |
|                              | Karst topography        |                             |

  The size, shape, and water-bearing characteristics of a hydrographic basin are important in evaluating
water resources. The characteristics could be more useful in selecting sites for ground-level study or drilling than knowing that indicators signify the presence of groundwater. Plants around a dry lake bed are
good indicators of groundwater. However, dry lake beds contain very fine-grained sediments; wells in these areas usually produce low water yields and contain poor quality groundwater. The rock or soil type
present could be the most important reservoir indicator as it usually defines the type of aquifer and its water-producing characteristics. For reconnaissance, it is only necessary to recognize three types of rock
and one type of soil:
a. Igneous Rocks. These are poor aquifers except where the rocks have been disturbed by faulting or
fracturing (see Figure 2-21). In many cases, these rocks are not capable of storing or transmitting groundwater and will act as a barrier to groundwater flow. In other cases, the stresses and movements
of mountain building may have resulted in fracturing of the rock. Groundwater can accumulate in
fractures and move through the rock if the fractures are connected. Most groundwater-bearing fractures
are within 500-ft of the surface, and drilling deeper to find water in igneous rocks is not advised. Wells in these aquifers are often poor producers and are seldom developed unless no other water source is available.
b. Metamorphic Rocks. These areas rarely produce sufficient groundwater and are considered an effective
barrier to groundwater flow (see Figure 2-21). Metamorphic rocks have poor potential for groundwater development.
c. Sedimentary Rocks. These areas have the greatest potential for groundwater development (see Figure
2-21). Sedimentary rocks are capable of supplying low to high yields if unfractured and moderate to
high well yields if fractured. Sandstone, limestone, shale, and evaporites are the four common types of sedimentary rocks.

Metamorphic

Sedimentary Rocks
Rocks
Igneous Rocks
Consolidated
(pores,
Extrusive (pores,
Groundwater
fractures, and
tubes, rubble
Unconsolidated
Supply
Source
(pores)
solution
openings)
Fractures
Intrusive
(fractures)
zones, and
fractures)
Large
Gravel
Sand
Sandstone
Limestone
Dolomite



Moderate to
small
Silt
Till
Coquina
Conglomerate
Siltstone
Tillite
Gneiss
Quartziteschist
Slate-schist
Marble

Balsalt and other
fine-grained igneous
rocks
Confining
beds
Clay
Marl
Shale



(1) Sandstone. Sandstone's ability to stem and transmit groundwater varies. If the sand grains are
small and tightly cemented together, a well will have a low yield, but if the rock has been fractured
extensively, a well could have a high yield. If the sand grains are relatively large and poorly cemented, moderate to high well yields may be possible.
(2) Limestone and dolomites. Undisturbed limestone and dolomites are poor aquifers, but limestone
may provide an excellent water source, where fractured. In some areas of the world, limestone areas are the principal groundwater sources. Fractures in limestone are more important than in
other fractured rocks because when groundwater moves through the fractures, it can dissolve the rock and enlarge the fractures. This process is called dissolution. Dissolution allows the rock to
store and transmit greater volumes of water than other types of fractured rocks. In most cases, limestone has been fractured and is considered the highest potential source of groundwater from
rock.
(3) Shale. Shale is fine-grained, does not usually store much groundwater, and does not transmit large
quantities of groundwater. Where fractured, shale generally can only produce a few gpm. However, identifying shale units is important because shales may indicate that artesian conditions exist in
more productive water-bearing units below or between shale layers.
(4) Evaporites. Evaporites are generally capable of storing and transmitting groundwater but tend to
dissolve in the water. Groundwater from evaporites is often unfit for human consumption and often not fit for any use. Because of the poor water quality, evaporites are generally considered to have poor potential for development. Because evaporites can dissolve in the water during drilling,
immediate surface areas may collapse; causing potential injury to personnel and destruction to
equipment. Special protective measures must be taken when developing a well in evaporites.
d. *Alluvium*. Groundwater is most readily available in areas under soils (unconsolidated sediments). This
is largely because uncemented or slightly cemented and compacted materials have maximum pore space, are relatively shallow, and are easily penetrated. Soils deposited by running water are called alluvium. Alluvium was formed in relatively recent geologic time and is generally restricted to lowland terrain features, such as alluvial valleys, terraces along rivers, alluvial fans, glacial outwash plains, and alluvial basins and between mountains and coastal terraces. Factors that have an important bearing on groundwater yield in soils are particle size, cleanliness (percent of suspended sediment), and degree of
sorting or gradation (e.g., clay yields almost no water; silt yields some, but very slowly; and a wellsorted, clean, coarse sand or gravel yields water freely).

(1) Valleys. Alluvial valleys are one of the most productive terrains for recovering groundwater (see
Figure 2-22). Normally, sand and gravel form a large part of the stream alluvium so that wells
located in the alluvium are likely to tap a good aquifer or series of aquifers. Individual aquifers do not usually extend far, and the number and depth of water-bearing sands and gravels changes rapidly from place to place.

 Alluvium tends to become progressively finer downstream as the stream gradient decreases and the
distance from outcrops of rock increases. In lower stream courses far from hard-rock highlands,
alluvium is mostly silt and clay, with a few sand stringers. A shallow well has a small chance of striking such a sand stringer. The sands may be so fine-grained that most wells will have small or
moderate yields. For large supplies, several wells or deeper wells may be needed.
(2) Stream and coastal terraces. Stream and coastal terraces are usually underlaid by gravel or sand
deposits similar to floodplain alluvium. If the terraces are fairly broad and the deposits thick, they may be good water sources (see Figure 2-23). In areas, terraces are so deeply trenched by stream erosion that most of the groundwater rapidly drains out of the terrace gravels through the streamcut slopes. Well drillers must be aware of the possibility of saltwater intrusion problems when drilling in coastal areas.
(3) Fans. Alluvial fans are found where steep mountain slopes rise abruptly from adjacent plains (see
Figure 2-24). Streams coming from the mountains drop coarse material near the apex of the fan and
progressively finer material down the slope. At the toe of a large fan, the deposits are mostly silt and clay, with few sand stringers. Alluvial fans often produce groundwater at depths greater than
alluvial valleys. Aquifers are abundant near mountains and often have a braided pattern with individual beds that are limited in extent. However, to reach water may require drilling several
hundred feet. Large boulders, which are common at the apex of the fan, can make drilling difficult.
Down the slope of a fan, aquifers get progressively thinner (pinch out). In the lower part of a large
fan, test drilling may be needed to locate a productive bed.
(4) Basins. Alluvial basins are in regions where mountains alternate with structural troughs (see Figure
2-25). The products of erosion from the mountains partly fill the basins with alluvium laid down as a series of coalescing alluvial fans. The upper alluvial slopes form piedmont plains or alluvial aprons that gradually decrease in slope toward the interior of the basin until they merge with the interior flats. Lakes or playas occupying part of the central flat are usually saline. Lake-bottom deposits are largely clay. Many alluvial basins are good sources of groundwater. Good wells yield
several hundred to a thousand or more gpm.
(5) Glaciated regions. Glaciated and post-glaciated areas can yield water from glacial deposits (see
Figure 2-26). Large quantities of alluvium laid down by steams emerging from glaciers (glacial
outwash) contain a higher percentage of gravel and coarse sand than clay. Such areas are good sources of groundwater. Extensive deposits occur in all glaciated regions of the earth, especially in
the northern United States, northern Europe, and areas bordering high mountains. Many large cities, including some in the upper Mississippi basin, get their water from glacial outwash
sediments.
  Glacial till aquifers are generally good water-bearing units. Glacial till was deposited directly by
ice into U-shaped valleys to form buried glacial valley aquifer systems - consisting of till and outwash. These may be very high producers of groundwater, and many serve as the primary
drinking water source for millions of people (e.g., Dayton, Ohio). In places where outwash sands
and gravels are interbedded or associated with the till, good aquifers form. Some of these aquifers may carry water under pressure.
e. *Stratigraphic Sequence*. The stratigraphic sequence of geologic strata that occurs in an area can give
clues to the types and depths of aquifers present. Figure 2-27 shows a stratigraphic column for a
portion of the arid Great Basin. The Great Basin contains a number of individual rock units. Some of
these units, such as the Ely Limestone, can readily transmit water, but other units, such as the Eureka Quartzite, are relatively impermeable and cannot store or transmit exploitable quantities of groundwater. Relatively impermeable units are aquitards or aquicludes. Aquitards are units that retard or slow the passage of water.
  In the stratigraphic sequence, there are five discrete aquifers and six discrete aquitards. By knowing the
stratigraphic sequences in a region, it is possible to predict the type of aquifer present at a given depth, For example, the Ely Springs Dolomite is not highly fractured, but the dolomite is a productive aquifer
where it is fractured. Because this unit is not overlain in the area by an aquitard, it could be an
unconfined aquifer. The stratigraphic sequence indicates that the Eureka Quartzite underlies the aquifers and is an impermeable barrier or aquitard. This unit is underlain by the Pogonip Group that
could provide suitable quantities of groundwater. Because this unit is overlain and underlain by aquitards, it is a confined aquifer. By using a geologic map, it is possible to estimate the thickness of
each unit and the anticipated well depth. If data exists for this aquifer in other areas, it may also be possible to predict the expected well yield and groundwater quality.
  In unconsolidated sediments, the stratigraphic sequence is usually less extensive, more variable, and
not as well known as rock. Alluvial deposits often consist of interbedded gravel, sand, silt, clay, mixtures of these materials, and, possibly, interbedded evaporite deposits. These sediments often occur
in complex stratigraphic sequences with some units discontinuous and other units grading into different soil types vertically and horizontally. Unless sufficient existing well data is available, it is impractical to define the stratigraphic sequence of such sediments.
f. *Structure Density and Orientation*. Geologic structures, such as folds, fractures, joints, and faults, are
features that disrupt the continuity of rock units. For groundwater exploration, identifying folds has a limited use but identifying faults and fractures is important, especially in rock aquifers. The ability of rock aquifers to transmit groundwater is related to the number and size of fractures in the rock. Density
of fractures is an important consideration in locating well sites in rock terrain. Figure 2-28 shows a
structure map of part of western Iran. The best potential well sites are located at the intersection of
fracture zones. Secondary sites are along individual fracture zones. Areas with no fractures are probably low permeability areas and poor sites for water wells.
  Fracture orientation is an important characteristic of rock aquifers and of soil aquifers. Faults may act
as either barriers to or conduits for groundwater flow. To distinguish between fault conduits and fault barriers, vegetative indicators are important. If a fault zone is acting as a barrier to groundwater flow,
groundwater accumulates behind the barrier and often becomes shallow enough to support springs or dense stands of vegetation, or it forms wetlands (see Figure 2-29).
g. *Dissolution Potential*. Dissolution potential is the potential for the development of high secondary
permeability in a soluble rock because of the dissolution of the rock through contact with groundwater.
Unfractured soluble rocks, such as limestone, have a low permeability referred to as the primary
permeability of the rock. Where fractured, the rock has a secondary permeability that is related to the
size and density of the fractures. If the rock is soluble and saturated, the contact between the groundwater stored or moving through the fractures and the rock may result in dissolution of the rock.
  The dissolution process increases the size of fractures and can result in an increased secondary
permeability. Many of the world's caves and sinkholes (karst topography) result from limestone dissolving in groundwater and are indicators of high dissolution potential. However, if such features
are not present, dissolution potential must be estimated on the basis of rock type and structure density. The highest dissolution potential occurs in heavily fractured carbonates (limestone and dolomite) and evaporites. Other rock types generally do not dissolve in groundwater and identifying dissolution
potential is of little use.
h. *Grain Size and Sorting*. The grain size and sorting of an aquifer is related to the porosity and
permeability of the aquifer and the production capability of the aquifer. Fine-grained materials (clay) have a high porosity, but a very low permeability and are poor aquifers. Sands have moderate porosity (about half that of clay), high permeability, and are usually productive aquifers. Generally, well production capacity is directly proportional to grain size. Areas of fine-grained sediments (playas and
lake beds) have poor water-production potential. Areas of coarse-grained sediments (alluvial fans) have
a higher potential.
i. *Lithification*. This is the process by which sediments are converted to rock. Lithification includes
compaction, consolidation, cementation, and desiccation. The degree of compaction or consolidation affects the porosity and permeability of an aquifer (see Figure 2-30). Porosity and permeability of unconsolidated materials (subjected to little or no overburden pressure) are related to grain size. With
compaction and consolidation, the pore spaces between grains are reduced and the porosity and
permeability of the aquifer are decreased.
  Another source of lithification is the cementing of grains by the precipitation of minerals from solution in the
groundwater. Many fragmented sedimentary rocks are cemented by silica or calcium carbonate precipitation from the waters they are deposited in or from waters introduced after they are deposited. Cementation often occurs along fault zones where deep mineral-rich water migrates upward. When the minerals and water mix, they precipitate travertine or other minerals along the fault zone. This can result in barriers to groundwater
flow in areas selected as potential well sites on the basis of the fault zones.
j. *Drainage Basin Size*. Because most groundwater is derived from the infiltration of precipitation over an
area, the size of individual drainage basins can help define the overall groundwater potential. Large drainage basins may receive more precipitation and have a larger groundwater supply than smaller
basins. This is true where precipitation is the same over a region; however, it may not apply in areas of
high relief, variable climate, or in arid regions.
  Perhaps the most useful areas where drainage basin size can give an indication of groundwater
potential is in mountainous terrain near coastal areas. In such areas, the larger drainage basins receive
more recharge from precipitation. This recharge flows toward the coast and the areas of highest
groundwater potential occur along the coastal plains adjacent to the larger basins. In arid environments, recharge usually coincides with areas where surface water drains from the mountainous areas and infiltrates into the groundwater system. The magnitude of this infiltration usually depends on drainage basin size and on the groundwater resource potential of the area.
k. *Landforms*. Identifying landforms with drainage patterns can help identify rock types in areas without
geologic maps. Landforms can provide information related to water depth, well-production potential,
and water quality. Figure 2-31 lists landform classifications with hydrogeologic conditions that may be based on the presence of the landforms.
l. *Elevation and Relief*. Elevation and relief provide an idea of the amount of groundwater replenishment
within a drainage basin and its groundwater potential. In a region of about the same latitude,
precipitation distribution is related to the elevation of the area with zones of higher elevation receiving
more precipitation than lower areas. A small drainage basin at a high elevation may receive appreciably more recharge from precipitation than a much larger basin at a lower elevation. Relief also has some effect on groundwater recharge. Areas with high relief (valleys bounded by prominent mountain ranges) have well-defined and easily identifiable recharge areas. In broad plains or plateaus, moderate
relief does not indicate recharge areas; requiring other indicators (grain size or drainage density) to be used.
m. *Drainage Pattern and Density*. Recognizing drainage patterns can help define rock types, recharge
areas and potential, as well as general hydrologic conditions of an area. Without geologic maps or other
information on rock types, classification of the drainage pattern and landforms can provide an accurate
interpretation of rock types and recognition of the area's structure. Because most groundwater recharge
occurs as infiltration of surface water drainages, areas with high drainage densities receive more
recharge than areas with low drainage densities. Recognizing drainage patterns and density can provide indications of the type of aquifers, the magnitude of recharge in an area, and directions of groundwater
flow. Figure 2-32 shows some of the more common drainage patterns. Rock has widely spaced rectangular or branch-like (dendritic) patterns and alluvium has medium to widely spaced parallel drainage patterns along valley areas and floodplains.
2. *Boundary Indicators.* These are characteristics that are indicative of local or regional groundwater flow
systems. By identifying the boundaries of flow systems, it is possible to define directions of groundwater flow and to estimate the depth and quality of groundwater within an area. Boundary indicators do not
directly indicate the presence of groundwater in an area.
a. *Recharge Areas*. These are areas where the groundwater reservoir is replenished. Recharge may be
derived from the runoff of precipitation into rock fractures in mountainous areas, leakage along
streambeds or under lakes, or the flow of groundwater from up-gradient areas. Figure 2-33 shows a sketch map of a hydrographic basin with identified recharge areas. Some recharge occurs in mountain areas as direct infiltration. The precipitation that does not infiltrate runs off into the local drainage network. Some recharge occurs along the streambeds and the remaining runoff discharges on the alluvial fans where it infiltrates. Precipitation over the valley floor is channeled, and quantities of
recharge occur along the valley drainage system. Various amounts of recharge are derived from lakes,
ponds, or channels that may occur within the basin.
  The recharge of groundwater from surface water sources usually results in a mound (bulge) in the
surface of the groundwater (see Figure 2-34). Groundwater in such areas flows away from the recharge
sources. If the source is a lake, flow is radial away from the source. If the source is a linear source
(mountain range or a stream), the groundwater divides and flow is primarily in two directions from the
source. Areas recharged by direct infiltration or precipitation usually contain good quality groundwater.
Groundwater under lakes may exhibit poor water quality because evaporation of lake water may increase the concentration of chemicals in the lake and any recharge derived from the lake.
  Groundwater recharged from streams is usually intermediate quality between groundwater recharged
by precipitation and lakes.


Landforms
Hydrogeologic Characteristics
Mountains are usually recharge areas and
locations of flow system boundaries.

Mountains
Mass
Range
Chain

Plains
Active river floodplain
Structural plain
Playa
Other alluvial plains

River floodplains and playas are usually
discharge areas, and have fair to poor
water quality. Structural plains have little
groundwater potential. Valley plains
typically have good potential because of
high transmissivity.

Wind-formed features typically indicate the
lack of recharge and very low groundwater
potential at shallow depths although deep,
confined aquifers may exist.
Wind-formed features
Yardang
Dune
Blowout
Deltas and alluvial fans are recharge areas
for surface runoff. Swamp, marsh, and
wetlands are discharge areas and indicate
shallow water. Badlands indicate the lack of
a shallow water table.
Water-formed features
Terrace
Alluvial fain
Delta
Swamp, marsh, and wetlands
Natural lake
Badlands

Marine-formed features indicate very
shallow but saline groundwater.
Marine-formed features
Beach
Tidal flat
Man-made lakes and pits are often
recharged areas as are areas adjacent to
embankments and mounds. Tailings piles
may be located near existing dewatering
wells inside mines.
Man-made features
Mining pit
Tailings pile
Embankment
Mound
Lakes

  Subsurface recharge from adjacent basins is often difficult to assess. By knowing the elevation of
groundwater in adjacent areas, the transmissivity of the aquifer, and the width of the recharge area, it is
possible to estimate the amount of recharge from subsurface flow. This estimate usually is not possible
in areas with limited data. It is possible to infer that such flow is occurring on the basis of differences in elevation and the location of barriers or conduits between hydrographic basins.
b. *Discharge Areas*. Recharge to and discharge from a hydrographic basin must be equal. Figure 2-35
shows a sketch map of a hydrographic basin with identified discharge areas. Figure 2-36 shows the directions of groundwater flow from the recharge to the discharge areas. Groundwater discharge can
occur in streams and lakes through consumption by plants or man and by subsurface flow to adjacent down gradient basins.
  The location of discharge areas can help identify areas of shallow groundwater. Streams sustained by
groundwater seepage, wetlands, and certain types of vegetation indicate discharge areas where groundwater is close to land surface. Some types of vegetation are capable of sending tap roots to
depths of over 100 ft and are not indicative of shallow groundwater. The location of subsurface
discharge areas requires more detailed knowledge of the hydrologic balance of the area.
c. *Impermeable and Semipermeable Barriers*. The quantity and rate of groundwater flow from recharge
areas to discharge areas are controlled by the transmissivity of the aquifers. Impermeable barriers are
those features (solid rock masses) through which groundwater cannot flow. Semipermeable barriers are those features (faults or fractured rock masses) that restrict flow but do not act as a complete barrier.
Such features should be recognized because they usually form the boundaries of groundwater flow
systems and, when located within a flow system, can result in areas of shallow groundwater.
d. *Surface-Water Divides*. Surface-water divides can form boundaries between groundwater flow systems.
The mounding of groundwater under areas that receive recharge from the infiltration of precipitation
causes groundwater to flow away from the recharge area. Similarly, surface water flows away from
topographic highs that often correlate with groundwater recharge areas so that surface-water flow
patterns usually coincide with groundwater flow patterns. The identification of surface-water divides
can help define groundwater flow systems.
3. *Surface Indicators.* Surface indicators are those features that suggest the presence of groundwater. These
indicators can provide information about the depth, quantity, and quality of the groundwater resources in an area; however, they do not positively indicate the presence of groundwater. The resource potential of an area is an inference on the basis of the presence (or absence) of certain indicators and particularly the
association of these indicators.
a. *Springs*. Springs are effluences of groundwater occurring where the water table intercepts the ground
surface. Springs are usually good indicators of the presence of shallow groundwater occurrences.
However, the presence of shallow groundwater may not be indicative of a good area for well
construction. Springs occur where groundwater discharges from the earth's surface. Figure 2-37 shows several types of springs. Faults, valley-depressions, and alluvial-fan springs may discharge appreciable quantities of groundwater.
b. *Vegetation Type*. Certain types of vegetation (or vegetative assemblages) are associated with specific
hydrogeologic environments. Some plants (phreatophytes) can only exist if their root systems are in direct contact with groundwater. Phreatophytes, such as mesquite tress, have tap roots that go down more than 100 ft. Shrubs, such as saltbush, have roots that descend only a few ft, making them excellent indicators of shallow groundwater. Figure 2-38 lists several plants that indicate the presence
of shallow groundwater. The density of vegetation can help define the location of recharge and
discharge areas. Dense stands of vegetation along stream channels are riparian vegetation. Riparian
vegetation along streams that discharge mountainous watersheds indicates that surface water is infiltrating the streambed and recharging the groundwater. In many cases, the vegetation decreases in
density after the stream reaches the valley floor. Somewhere along the streambed, the riparian
vegetation assemblage gives way to the typical valley-floor vegetation.
c. *Playas*. These are dry lake beds composed mainly of clay and located in intermountain valleys (see
Figure 2-39). During rainy seasons, playas may store large quantities of surface water.
d. *Wetlands*. Wetlands such as marshes, bogs, and swamps are indicative of very shallow groundwater.
Although wetlands are not typical of arid environments, they have been observed in arid flow systems where groundwater accumulates behind flow barriers. Wetlands can also occur in low-lying areas
where the discharge of regional spring water accumulates. The presence of wetlands is an excellent indicator of groundwater. However, wetlands generally are not suitable for water-well locations because of low permeability of wetlands soil, marginal water quality from the evapotranspiration
processes of wetlands vegetation, and severe mobility constraints. Wetlands are important in groundwater detection because they usually represent regional discharge points. Areas up-gradient of wetlands are usually favorable targets for groundwater development.
e. *Streams and Rivers*. Streams and rivers (including dry streambeds and riverbeds) are usually recharge
areas in arid regions and may be recharge or discharge areas in temperate climates, depending on seasonal rainfall. This type of recharge is especially true of major streams that drain the central
portions of most valleys. Because recharge occurs along stream courses and streams occur in lower elevation areas in the valley, the areas adjacent to streams are considered good locations for wells, especially near the intersection of major streams. However, such locations are not always the best
available areas for water wells.
  Streams often migrate over large areas of the valley floor and deposit mixtures of gravel, sand, silt, and
clay. Often these deposits are discontinuous and result in a vertical sequence of poorly sorted materials with low overall permeability and low to moderate well yields. Older, buried stream channels may be better aquifers because they are composed of coarser sub-grade materials and much of the surface
contamination has been filtered out.
f. *Snow-Melt Patterns*. Snow-melt patterns can provide evidence of recharge areas and directions of
groundwater flow. Snow packed in mountainous areas is usually a good source of recharge because
slowly melting snow produces more infiltration than rainfall.
g. *Karst Topography*. Karst topography results from the dissolution of carbonate rocks by groundwater
and is characterized by caves, sinkholes, closed depressions, and disappearing streams (refer to Figure
2-18). These features indicate that the rock has a very high dissolution potential and that groundwater is present. Collapse-type sinkholes (irregular, debris-filled sinkholes) usually indicate the presence of shallow groundwater because they result from the collapse of the surface materials into a dissolution cave. In some cases, the water provides evidence of the depth to groundwater.
h. *Soil Moisture*. Soil moisture content can provide some indication of recharge and discharge areas.
Areas with high soil moisture are not necessarily areas with high groundwater potential and good water-well locations. Soil moisture content is related to local rainfall and to grain size. The smaller the
grain size, the higher the soil moisture. Playas and lake deposits often exhibit high soil moisture but
very poor groundwater potential, resulting in low well yields.

| Plant Species                            | Depth of Groundwater                    | Chemical Quality                    |
|------------------------------------------|-----------------------------------------|-------------------------------------|
| Rushes, sedges, cattails                 | At surface or within a few feet         | Generally good but not invariably   |
| Giant reed grass                         | At surface or probably within 8 ft      | Generally good but not invariably   |
| Wild cane                                | Near surface to 10 ft or more           | Generally good but not invariably   |
| Giant wild rye                           | Near surface to 12 ft or more           | Generally good but not invariably   |
| Salt grass                               | Near surface to 10 ft or more           | Good to very bad                    |
| Pickle weed                              | Generally within a few ft, but locally, |                                     |
| may be as much as 20 ft                  |                                         |                                     |
| Generally, highly mineralized            |                                         |                                     |
| immediately under the water table,       |                                         |                                     |
| but possibly a little better in          |                                         |                                     |
| deeper water                             |                                         |                                     |
| Generally good but not                   |                                         |                                     |
| invariably                               |                                         |                                     |
| Arrow weed                               | Surface to possibly 25 ft; heavy        |                                     |
| growth usually indicates water within    |                                         |                                     |
| 5 to 10 ft of surface                    |                                         |                                     |
| Palm trees                               | Within a few ft of the surface          | Potable water is generally found in |
| vicinity of healthy palms, but           |                                         |                                     |
| locally may be very bad                  |                                         |                                     |
| Willow trees                             | Surface to 12 ft or more                | Generally good                      |
| Good to very bad                         |                                         |                                     |
| Alkali sacaton                           | 5 ft or less to 25 ft, and in places    |                                     |
| much more luxuriant where depth to       |                                         |                                     |
| water table is 5 to 15 depth             |                                         |                                     |
|                                          |                                         |                                     |
| Rabbit brush                             | Luxuriant growth indicates water        |                                     |
| table at 8 to 15 ft (locally, as shallow |                                         |                                     |
| as 2 ft)                                 |                                         |                                     |
| Doubtfully, usually mineralized,         |                                         |                                     |
| but drinkable                            |                                         |                                     |
| Grease wood                              | 3 ft or less to 40 ft or more,          |                                     |
| abundant and luxuriant where depth       |                                         |                                     |
| is between 10 to 20 ft                   |                                         |                                     |
| Mesquite                                 | 10 ft or less to 50 ft or more          | Generally good but not              |
| invariably                               |                                         |                                     |
| Cottonwood trees                         | Abundant groundwater, generally         |                                     |
| good within 20 ft                        |                                         |                                     |
| Generally good                           |                                         |                                     |
|                                          |                                         |                                     |
| Desert willows                           | Generally indicates shallow             |                                     |
| groundwater; local water table may       |                                         |                                     |
| be at 5 ft or more                       |                                         |                                     |
| Elderberry shrubs and small trees        | Generally within 10 ft of the surface   |                                     |
| Alfalfa                                  | 15 to 60 ft, luxuriant growth where     |                                     |
| water is within 15 ft                    |                                         |                                     |
|                                          |                                         |                                     |

i. *Salt Encrustation*. Salt encrustations often occur in playas and are indicative of saline groundwater
(refer to Figure 2-39). Often, salt buildups result from the evaporation of surface water and can cover many acres. Certain salt-tolerant plants may grow in such areas, indicating shallow groundwater
containing high concentrations of sodium, potassium, and other soluble salts. Although salt encrustations indicate shallow groundwater, drilling for groundwater should be avoided even if water treatment equipment is available. Surface salt deposits usually indicate deep evaporite deposits. Subsurface evaporite deposits are very susceptible to collapse and should be avoided.
j. *Wells*. One of the best indicators of groundwater is existing groundwater development with well
systems. Water wells are difficult to detect, especially from imagery. It is possible to detect wells
indirectly from irrigation patterns. Pivot irrigation patterns (see Figure 2-40) are distinctive and are usually supplied by centrally located water-supply wells. Such features are good indications that
quality groundwater is present at economic pumping depths.
k. *Reservoirs and Lakes*. Surface water bodies provide groundwater recharge, discharge, or both.
Artificial surface water reservoirs usually capture surface water and represent areas of recharge, as do natural reservoirs created by the damming of streams. Natural reservoirs in lowland areas are often formed by the discharge of groundwater from seeps along the lake bed or from springs.
l. *Crop Irrigation*. Crop irrigation indicates the use of surface or groundwater for agriculture. In most arid
environments, surface waterbased irrigation is located adjacent to streams and rivers. Beyond the river floodplains, agriculture is negligible. Agricultural development in areas without surface water is a good indicator of the presence of groundwater at relatively shallow depths. The leaching action of irrigated
water and the use of chemical fertilizers may impair the groundwater quality in such areas.
m. *Population Distribution*. Population distribution in arid regions or sparsely populated areas is closely
related to water availability. Because of the lack of resources and technical capabilities for wide-scale groundwater development projects, population centers in arid environments without surface water are
usually good indicators of groundwater supplies. These centers are often located on perched aquifers
with limited capabilities; the population sizes are directly proportional to the production capacities of
the aquifers.

## 2.8 Desert Environments

For contingencies, water-well drillers shall become familiar with drilling OPS in an arid or desert environment. An arid environment usually has less than 300 millimeters (mm) of rainfall per year and high average daily temperatures. Most of the soils are coarse-grained with high porosity and permeability. Because of low rainfall, only deep water tables may exist. Therefore, any well drilling units and equipment or kits deployed to a desert OA should be capable of achieving maximum depth of 1,500 ft. Generally, the more arid the region, the greater the controls the HN will place on well-drilling activities because of the potential impact of drilled wells depleting scarce aquifers. The HN may also require more detailed documentation on the water sources. Because of the amount of water consumed during desert OPS (up to 20
gallons daily per person), the challenge may not be in locating and drilling for water, but in finding who can identify water sources and give permission for using the sources. In desert mountain areas, wells should be sited on the alluvial fans that extend from the mountains to the desert
(see Figure 2-41). Mountain areas usually receive more rainfall, and the streams draining away from the mountains carry coarse gravels and sands that, when deposited, produce the fans (see Figure 2-42). At moderate depths, these fans may yield water. In deserts such as in Egypt, Jordan, and Saudi Arabia, deep confined aquifers are capable of producing extensive quantities of water. Locally, shallow confined aquifers come to the surface at an oasis, characterized by more extensive vegetation than the surrounding areas (see Figure 2-43). Wells may be sited in the vicinity of an oasis to tap a confined aquifer. Qanats are good indicators of groundwater in some desert areas like Iran. A qanat is a man-made, gently inclined underground channel that allows groundwater to flow from alluvial gravels at the base of hills to dry lowlands (see Figure 2-44). In effect, qanats are horizontal wells. On aerial photographs, qanats appear as a series of antmound-like openings that run in a straight line and act as air shafts for the channel. They may be found in arid regions of Southwest Asia and North Africa. Qanats may be up to 30 kilometers in length.

## 2.9 Water Quality

Most water is run through reverse osmosis water purification units (ROWPUs) or tactical water purification systems before it is used, so the effect of contamination is minimal. The list below describes different types of contamination in more detail:

1. *Aquifer Contamination.* Military engineers must be aware of possible aquifer contamination. As
groundwater is transmitted from recharge to discharge areas, it contacts soils and rocks of the earth's
crust. Contact causes some dissolution of soil and rocks into the water and alters the chemistry of the
groundwater. Discharge areas that appear to be good well sites because of shallow groundwater may
have poor water quality and may be poor sites for groundwater development. Discharge areas often correspond to zones of poor water quality. Generally, the longer the distance between the recharge and discharge areas, the poorer the water quality at the discharge area. The water-quality reduction is from the contact between the groundwater and the aquifer material during flow. Water consumption
by plants often results in decreased water quality by the concentration of soluble salts in the
groundwater.
  In very shallow groundwater (less than 10 ft below land surface), water quality can be decreased by
direct evaporation of water from the soil. The use of vegetation type helps infer groundwater quality
characteristics. Saltbush around playas indicates not only the presence of shallow groundwater but
also the probable occurrence of saline water, which would require treatment. The high evaporation
rate in arid environments concentrates chemicals in the water, resulting in brackish or saline water
quality.
2. *Saltwater Intrusion.* Saltwater intrusion into fresh groundwater is a problem in coastal areas and on
islands. Salt water is unfit for most human use and is harmful to automotive cooling systems, boilers, and
other types of machinery. Chemical analysis determines the accuracy of contamination and salt levels. The
average concentration of dissolved solids in sea water is about 35,000 parts per million (ppm) (3.5 percent). Most salts are chlorides.
  Fresh water floats on salt water when salt water and fresh water are present in sediments. Contact between
the two is determined by the head of the fresh water above sea level and by the relatively greater specific
gravity of the salt water. The average specific gravity of sea water is about 1.025 (taking pure water as 1.000). For every foot of fresh water above sea level about 40 ft of fresh water is below sea level in homogeneous soils. The condition is best exhibited by small islands and peninsulas composed of permeable sands surrounded and underlain by salt water (see Figure 2-45). The head of fresh water and
resistance of the pores in sand prevents salt water from entering the middle zone and mixing with fresh
water. The diffusion zone (contact) between fresh water and salt water is narrow (less than 100 ft wide) unless affected by heavy pumping.
  The amount of fresh water that is pumped without intrusion of salt water depends on local conditions, type
of well, rate of pumping, and the rate of recharge by fresh water. Any decrease in the head of fresh water by pumping or decrease in rainfall raises the saltwater level (see Figure 2-46). The cone of depression (drawdown) produced in the freshwater level around a well allows a corresponding rise in the underlying salt water. Pumping a well should be restricted because salt water will enter the well if drawdown is maintained substantially below sea level for extended periods. The pumping rate should not exceed the rate of recharge. Saltwater intrusion is a potential problem when drilling in coastal-plain environments.
Salt water may move into zones previously occupied by fresh water, this is called saltwater encroachment. The fresh water and the salt water migrate toward the well screen until a new balance between the waters
is established (see Figure 2-47).
3. *Groundwater Contamination.* Possible aquifer contamination from human activities should be considered
when evaluating potential supplies of groundwater. Waste products are sources of groundwater
contamination in some areas. Sources of waste products include agricultural activities; domestic,
municipal, and industrial waste disposal OPS; mine spoil piles and tailings; and animal feedlots.
  Figure 2-48 shows how waste contamination enters the groundwater. Groundwater pollution occurs in
both urban and rural areas and is affected by differences in chemical composition, biological and chemical
reactions, density, and distance from discharge areas. Non waste pollutants include leaks from buried pipelines, highway deicing (salting), pesticide and herbicide applications, and accidental spills from
surface transportation and manufacturing activities. Supplemental information on WRDB overlays often
indicates the severity of man-induced pollution. Especially important are aspects of bacterial
contamination that will preclude the use of the groundwater prevalent in many developing countries.
Groundwater contamination may also occur from other wells into the same aquifer; requiring exercise control or coordination over aquifer access which is a challenge in water stressed regions. Well drillers should consider the proper location of water wells as shown in Figure 2-49.
Small wells often have shallow aquifer sources. It has been shown that sources a few feet below the surface can be reached by septic tanks, outhouses, and human waste. Locate wells at higher elevations than potential contamination points. Some minimum distances from potential biological pollution sources have suggested in Gibson's *Water Well*
Manual for sand filtration capacity soil. As a minimum, a well should not be located within: (1) 10 ft of a cast curb sewer or sewer lines; (2) 50 ft of a septic tank or tightly jointed tile sewer; (3) 75 ft of an earth pit or drain field; (4) 100 ft of a cesspool with raw sewage (although the United States (US) Public Health Service recommends at least 150 ft).

Gibson, U.P. and Rexford D. Singer, *Water Well Manual*, p. 156.

INTENTIONALLY BLANK

## Chapter 3 Field Operations 3.1 Team Concept

The list below describes the water-well drilling team concept and key positions:

1. *Leader/tool pusher/officer in charge (OIC)*. Well drilling teams deploy to the field to construct water
wells. These teams normally deploy with the organic equipment they use to drill and complete the well.
Teams are manned for continuous OPS and consist of two complete drilling crews, a mechanic, and a detachment leader. The detachment leader is usually responsible for:
a. *Training and caring of team members.*
b. *Caring and maintaining of team's organic equipment.* c. Coordinating with the supporting engineer unit. d. Deploying the team. e. Laying out the drilling site. f. Developing safety guidelines for the well drilling team.
2. *Driller*. A drill team, which consists of a driller and two helpers, operates the drilling rig. A driller's
responsibilities include:
a. Operating and controlling the drilling rig. b. Establishing (and modifying when necessary) the drilling rate. c. Monitoring mud mixture and sufficient volume. d. Monitoring the drill cuttings. e. Maintaining a driller's log of the well. f. Preventing accidents around the drilling rig.
3. *Helper/derrick*. A helper is responsible for:
a. Making drill rod connections. b. *Ensuring an adequate mud mixture during drilling.*
c. Maintaining and caring for the rig, tender, and tools during the drilling operation.
4. *Worker/oiler/repairman/maintenance/mud man (WORMM)*. A WORMM is responsible for:
a. Conducting clean up of site, shovels pits, and keeps supplies handy. b. Checking and lubricating the rig at prescribed intervals during shift.
c. Making small repairs to rig and support equipment onsite. d. Coordinating all pre and post operator maintenance of all equipment. e. Ensuring the mud program is good; adds products as directed by driller.
5. *Mechanic.* A mechanic is responsible for:
a. Performing repairs on the rig and auxiliary equipment. b. Supporting the team where needed in support of drilling OPS.

## 3.2 Team Planning, Coordination, And Preparation

A well-drilling team's primary responsibility in planning and preparing for a drilling operation is to maintain a state of readiness. They must train, practice, and discuss OPS continuously. They should study information about specific sites and determine alternate solutions to potential problems. Periodically, teams should check each component of the well drilling equipment. Team members must maintain drilling rigs and tender trucks in good operating condition. Before leaving for the mission area, teams should inventory all tools, parts, drilling accessories, and supplies. Planning requirements to support well drilling teams are similar to those needed for any augmentation team. Well drilling teams do not have an organic headquarters. Well drilling teams should be deployed and employed by an engineer unit capable of providing equipment, maintenance, administrative, and logistical support. Water wells are engineer construction projects and must be planned, researched, managed, inspected, and reported just as any other project. The unit that the well drilling team is attached to should provide the team with construction (field or tactical) standing operating procedures (SOPs). The team should report well drilling progress and procedures according to the SOP. The well drilling project should be managed by the critical-path method (CPM). The well drilling team's commander must coordinate and work closely with the construction or OPS officer of the supported unit to ensure timely researching and reporting. When well drilling teams complete the well drilling mission, they turn the well over to the OPS officer for disposition. The team then moves to the next project. The OPS Officer arranges transfer of the completed well, operating equipment, and technical specifications to a water-purification team, an installation, or a HN official.

Well drilling teams are in great demand in most OAs. Teams may not be able to return to a well site to perform repairs and keep up with the anticipated work load. The senior engineer of the supported unit has to set priorities for the team's work schedule and should consider including the repair of existing and recently drilled wells in work estimates. The senior engineer must also determine if the teams have the skills or equipment needed to repair the wells before filing a request. The unit's OPS section, in coordination with the well drilling team, should prepare a construction estimate to determine the needed support for the well drilling operation. Team experience and land formations dictate the length of a well drilling operation. Staff personnel should consider the following when planning for the augmentation of a well drilling team:

1. Transportation of the well drilling team's equipment and personnel by land, air, or sea, according to the
unit movement books and operator manuals.
2. Reconnaissance and route selection to mission sites.
3. WDRT assistance and graphic products from the WRDB to select a potential drilling site.
4. Security during movement and drilling OPS. 5. Earth-moving assets to clear and level the drilling site and excavate mud pits. 6. Material handling equipment to offload well-completion kit materials, as needed. 7. Administrative support, including postal and legal services. 8. Logistical support, including all classes of supply and arrangements for mess; petroleum, oils, and
lubricants (POL); maintenance; and medical support.
9. Delivery of the initial drilling water supply, if required.
10. Turnover of the completed well to a water-purification team, installation, or HN official.
11. Well-completion kit or component resupply. 12. Communications support. 13. Reporting procedures. 14. Planning for the next mission.

## 3.3 Deploying Teams

Well drilling units are considered and organized as a specialized skill team. They are not self-sufficient. These teams depend on an engineer unit or a HHQ that is capable of providing support needed to accomplish the mission.

A well drilling team leader must ensure that the unit the team is attached to understands the mission and capabilities of the team. Because a well drilling team is small, there is little redundancy and no surplus labor. Therefore, the leader must request in advance any additional personnel needed to complete the mission. Since a well drilling team only has the equipment necessary to drill under optimum conditions the team leader must also request the following from the supported unit:

1. Transportation support of the equipment and personnel by land, air, or sea, according to the unit
movement books and operator manuals.
2. Routes to the proposed drill site. 3. WDRT assistance and graphic products from the WRDB and an indication of where the OA commander
wants the well.
4. Security during movement and drilling. 5. Clearing and leveling of the drill site. 6. Excavation and maintenance of mud pits. 7. Off loading and transportation of well-completion materials. 8. Administrative support, including postal and legal. 9. Logistical support, including all classes of supply with special emphasis on repair parts.
10. Mess and potable water. 11. Fuel and POL products and continual resupply. 12. Specialized maintenance, evacuation, and on-site welding support. 13. Medical support, including medical evacuation (MEDEVAC) procedures.
14. Initial water supply and resupply. 15. Timely delivery of pea gravel for gravel packing material. 16. Arrangements to turn over the completed well to the supported unit OPS cell. 17. Communications support.
18. Reporting procedures. 19. Resupply of well-completion kit materials for next mission. 20. Plans for the next mission.

## 3.4 Site Preparation

Most sites require some preparation before setting up the drill rig. In rugged terrain, teams may have to excavate into a hillside requiring the preparation of a drilling platform. The drilling platform (or drilling area) should be large enough so teams can safely operate each component during the drilling operation. Where excavation is not expedient, teams may have to construct mat or timber platforms to level the rig. Teams must consider locations for the rig and mud-pit, working areas, and well-completion components and accessories; location for and access to drill pipe racks; and location and maneuverability of the tender truck during the preparation phase. If a mud pit is needed and the drill rig does not have a portable mud pit or if the portable pit does not have sufficient volume, teams should construct a pit during the site-preparation phase.

Refer to Service-specific appendices and drill rig operator's manuals for drill rig set up.

Teams shall always place the drill rig on stable, level ground and clear the site of obstacles as well as any potentially combustible materials. Avoid setting the rig up on a fill area since the rig could overturn.

Check for overhead and underground power lines before moving the rig on site. Consider all power lines as being energized. Do not raise the mast around electrical wires without a ground guide. If power lines are a problem, teams must move the rig or make previsions for removal of the power lines. Check the clearances listed below:

- If the power lines have a voltage of less than 50 kilovolts (kv), place the rig at least
10 ft from the power lines.
- If the power lines have a voltage of more than 50 kv, place the rig 10 ft plus 0.4 ft
for every kv over 50 kv from the power lines.
Historically, groundwater coming from its natural environment is considered of good sanitary quality. Because of this, personnel must understand the effects well drilling may have on the surrounding environment. Layers of rock and different formations protect the groundwater supply from contamination. Drilling a hole through these protective layers provides an access for bacteria and chemicals that could degrade water quality. Well drillers must take precautions to ensure they will not contaminate the well and the aquifer.

## 3.5 Drilling Fluid

If using a rotary drill with mud, connect or place the suction line of the mud pump in the mud pit and fill the pit with water. When complete, close the standpipe valve and prime the mud pump. Mix the drilling fluid in the mud pit by slowly circulating fluid through the mud pump and adding drilling mud to the mixing hopper (see Figure 3-1). The drilling fluids usually used for mixing mud are a Wyoming-type bentonite drilling additive (Quick-Jel) or an organic or inorganic polymer fluid (Revert or E-Z Mud). Mix the additives until the desired weight and viscosity are reached for the drilling mud. Refer to Chapter 5 for additional details on mud mixing.

## 3.6 Well Drilling Ops

Before starting to drill, an appropriate drill bit must be selected. Consideration of the well diameter and the type of formations to be encountered are paramount. The types of bits are:

1. Drag bits. Use these bits for soil, unconsolidated materials usually found near the surface. 2. Tricone roller-rock bits. Use these bits for a variety of materials from soft formations through hard rock
(see Figure 3-2). These bits are available in different degrees of hardness. Bits used for softer formations have longer teeth on the roller cones.
3. Down hole hammer bits.  Use in consolidated, very hard material. Requires air compressor to operate.
The list below describes drilling OPS in more detail:

1. *Starting the Operation.* The first operation is spudding in (starting the borehole). Before starting to drill
the actual hole, consider drilling a 6 to 7-1/2 -inch test hole. Doing so will ensure that the larger hole is straight which should help locate the aquifer quicker. Use the following steps to start the drilling
operation:
- Step 1. Make up the drill bit on the collar and lower the bit to the ground. - Step 2. When the bit contacts the ground, start rotation and begin to drill. - Step 3. After the borehole advances 6 to 12-inches, engage the mud pump to start circulating the
drilling fluid (which will be mud or air).
- Step 4. After drilling down the collar, stop the rotation and raise the collar about 4-inches off the
bottom of the borehole. Circulate the drilling fluid until all drill cuttings are removed.
2. *Finishing the Operation*. As a section of the drill string is completed, lift the bit 4 to 6-inches off the
bottom of the hole to allow the cuttings to be removed by the mud pump. Once all cuttings are removed, add additional collars and drill rods until desired depth is achieved.

## 3.7 Sampling And Logging

Samples shall be recorded for every well drilled. During the drill operation, it is important to take samples of the cuttings in the drilling fluid (see Figure 3-3). Record the samples in a driller's log according to basic classifications (sand, clay, or granite) and describe their color and consistency (coarse or free) when possible.

Also, record the approximate depth of the sample. If samples are needed from a specific depth, stop the drilling operation and let the drilling fluid circulate until the cuttings reach the surface. Other information that must be recorded is advance rate, reaction of the drill rig, any loss of circulation, and changes in drilling fluid consistency. Periodically, check the drilling fluid for viscosity, weight, and sand content. Log the test results and any adjustments made. Finally, if the drill rig breaks down or needs repair or maintenance, record the information in the log. The information in the driller's log can provide insight into local conditions, help determine well-screen locations, and plan for additional or future well installations.

Always place the screen sections into the aquifer and not at the bottom of the hole.

## 3.8 Casing And Well Screen

Depending on the construction method, set the well casing in the well before or at the same time as the well screen. If the borehole has a tendency to cave in during drilling, install surface casing while drilling, but before reaching the desired depth (use this procedure when drilling in loose, unconsolidated materials). When installing the casing before the well screen, such as surface casing, the casing must be larger than the screen. Therefore, use a larger drill bit than the one used to complete the screen portion of the borehole. The decision to use surface casing should be made before mobilizing and should be based on the geologic information about the site. It is important to draw a diagram or working sketch of the well before setting the casing and screens; this practice will ensure optimum water collection due to proper screen placement. The list below describes surface casing, screening, and filtering and backfilling in more detail:

1. *Surface Casing*. Use the following steps to install the surface casing:
-
Step 1. Drill the borehole to a predetermined depth and remove all the cuttings by circulating the
drilling fluid. Withdraw the drill string and remove the bit.
-
Step 2. Connect the elevators to the first section of surface casing that is lifted over the borehole by using a casing elevator and the hoist (see Figure 3-4).
-
Step 3. Lower the casing into the well and set the slips (see Figure 3-5), which suspend the casing in
the well, in the spider base (see Figure 3-6).
-
Step 4. Disconnect the elevator, hoist the next casing section with the elevator, place it in the first
section, and join the two sections. Lift the string of casing slightly, remove the elevator from the lower
section, lower the casing, and repeat the process until the last casing section is suspended in the well.
-
Step 5. Grout the casing in place with a cement grout. After the grout sets (about 24 hours), resume
drilling OPS using a drill bit that will fit inside the surface casing. Drill the well to the desired depth, case, and screen the lower section of the well, using the single-string method.
2. *Screening*. Use the following method to install screens:
- Step 1. Place a casing section in the well. Cap the casing on the lower end so materials from the bottom
of the well will not enter the well.
- Step 2. Suspend a screen section over the well and attach the screen section to the casing section.
- Step 3. Lower the screen and casing section. Suspend them in the well either by the elevator resting on
the rotary table or by slips in the spider bowl.
- Step 4. Add casing until the screen reaches the desired depth. Refer to Chapter 4 for details on other
screening methods.
3. *Filtering and Backfilling*. The last procedure when installing screen and casing is to place a gravel-pack
filter around the screen and backfill material around the casing. If the screen is placed in material such as
gravel or very coarse sand, gravel pack may not be needed. Place the gravel filter material around the
outside of the casing and deposit the material to the bottom of the well. Add gravel to about 5 ft from the top of the screen (use the sounding method to determine the level of the gravel). Add impervious backfill around the casing from the gravel pack to about 10 to 20 ft from the surface. If grout is used instead of impervious material, add a couple of ft of clay above the gravel to prevent the grout from entering the
gravel filter and bring the grout to the surface.

## 3.9 Well Development

Frequently, when a well is first installed, the efficiency (production per foot of drawdown) is not satisfactory, requiring the development of the well by pumping, surging, or both. Developing a well removes the remaining drilling fluid, breaks down any filter cake buildup on the borehole wall, and flushes the fines in the formation
(adjacent to the gravel pack) into the well. Make sure that the well is pumped of all fine sediments and sand with an airlift before installing a submersible pump or the pump and components will wear out prematurely. Additionally, pump or blow the drilling fluid out of the well and agitate the water in the well to produce an alternating in and out flow through the well screen (or gravel pack). Although there are several methods available to develop a well the simplest method follows:

- Step 1. Attach a weighted plunger or surge block to the sand line. Lower the surge block into the well
below the water level, but above the screen.
- Step 2. Lift the block and then drop the block 3 to 4 ft, repeatedly, to surge the well. Continue this action
for several minutes.
- Step 3. Remove the surge block and lower a bailer into the well. All of the sand that was pulled into the
well is bailed from the sand trap.
- Step 4. Repeat the process, noting the amount of sand brought into the well each time. Development is
complete when 5 milligrams or less of sand per liter of sampled water is removed.
- Step 5. Sanitize the well with calcium hypochlorite.

## 3.10 Sanitary Seals

All wells must have a sanitary seal to prevent contamination from surface runoff. Mix cement grout and place it in the annulus between the well casing and the borehole wall. Next, extend the grout from the surface to the top of the backfill material (30-foot minimum). A concrete platform (about 4 ft by 4 ft) should also be poured around the casing at the surface with the casing extended at least 1 foot above the surface. The upper surface of the slab and the surrounding area should be gently sloping away from the well for better drainage. In addition to a surface grouting, a well seal (a type of bushing or packing gland) shall be installed to prevent foreign materials from entering the inside of the well casing. Normally the well seal is installed with the pump, which is after all development, testing, and disinfection.

## 3.11 Pumping Tests

After installing a well, a pumping test must be performed. The gpm, footage of drawdown, and available drawdown give an immediate indication of the well's capacity and whether the well can produce the required amount of water. If the well is considered permanent, the pumping test should help evaluate any future performance deterioration. A throttle or a valve on the pump should be installed to regulate water extraction and prevent pump damage if the pump from the well-completion kit is capable of producing more water than the well. Before starting the test, place a sounding device, such as an M-Scope, in the well to measure the water level during the test. The flow rate must also be measured and regulated during the test. The most proficient way to measure the flow rate is with a flow meter. However, a calibrated container and a stop watch may also be used.

Use the following procedures to perform the pumping test:

- Step 1. Temporarily install a pump in the well below the anticipated drawdown depth, but above the
screen.
- Step 2. Measure the static water level and start the pump. During the test, one team member should
monitor the flow rate and try to keep the flow rate constant.
- Step 3. Record the drawdown with the flow rate. Take early readings quickly; then spread out the readings
as testing progresses. An ideal reading schedule would be the initial reading and then a reading at 30 seconds, 1 minute, 2 minutes, 4 minutes, 8 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, and so forth. It is important to record the exact times that readings of the drawdown and flow-rate measurements are
taken. The length of a test usually depends on the purpose of the well, the urgency for water, and the time available. On small water supplies, an adequate evaluation takes 4 to 5 hours. For large, permanent
supplies, tests could take from days to weeks.
- Step 4. Set and adjust the pump. The well is now ready for use or for connecting to a treatment, storage,
and distributions system

## Chapter 4 Well Drilling Methods 4.1 Mud Rotary Drilling

Rotary drilling with mud is the most widely used method for water-well construction. A rotary drill rig has three functions: rotating the drill string, hoisting the drill string, and circulating the drilling fluid. A bit is rotated against the formation while mud is pumped down the drill pipe, through ports in the bit, and back to the ground surface through the annulus between the drill pipe and the borehole wall. Figure 4-1 shows the relative performance of drilling methods in various geologic formations. Drill cuttings rise to the ground surface in the drilling fluid. Rotary drilling is sometimes called mud rotary drilling. Drill pipes or rods are joined to a bit to form the drill string. The drill pipe is the link transmitting torque from the rig to the bit and carries the drilling fluid down the hole. The list below describes rotary drilling in more detail:

1. *Rotary Rigs*. Rotary rigs vary in design. Drilling rigs are truck-or trailer-mounted and are powered by an
on-board engine or by a power takeoff (PTO) from the truck transmission. Power is delivered to the
various components through hydraulic pumps and motors or through mechanical transmissions and
clutches and geared on roller-chain drives. Many drill rigs may use both mechanical and hydraulic drives. Torque is applied to the drill string, which rotates by using three basic designsrotary table, top head, and quill-and-drive bar. Military drilling machines use rotary tophead drives.
a. Rotary Table. The rotary table is a rotating platform that transmits torque to the drill rod through the
kelly. The kelly, which is attached to the mud swivel, is the uppermost section of the drill string that passes through the rotary table. The drill string may be square, hexagonal, or round with grooves or flukes on the outside wall. The drive kelly bar slides through the rotary table while rotating. By removing the kelly bar, drill pipe can be added and worked through the open hole in the rotary table. The rotary table normally is a mechanical, positive drive mechanism.
b. Top Head. The top-head drive uses a power swivel. Torque is applied at the top of the drill string. The
top-head mechanism moves down along the rig mast as the boring is advanced and is raised to the top of the mast to add a length of drill pipe. Top-head-drive drill rigs do not use a kelly bar. Most top-head drives are powered by hydraulic motors capable of variable speeds rather than positive constant rotation.
c. Pulldown. Rotary rigs are equipped with a mechanism to apply a downward thrust to the drill string.
This mechanism is called a pulldown or feed drive.
  Generally, two roller chains apply the thrust for rotary tables. The chains are attached to the kelly
swivel and extended over sprockets at the top of the mast and under the rotary table. On older rigs, the
sprockets under the rotary table are powered mechanically through a PTO and clutch. The pulldown
chains on modern drill rigs are powered by a hydraulic motor, which provides better thrust control.
  The thrust mechanism on most top-head rigs consists of a pair of roller chains in two chain sections.
One end of each section is attached to the swivel at the top of the kelly bar. The other ends are deadheaded to the top and bottom of the mast. Sprockets at the top and bottom of the mast act as idlers.
Chains are powered in either direction by hydraulic rams. These rams apply thrust and are used in a hold-back mode to reduce the bit load of the weight due to the drill string. This chain mechanism is also the main hoist for lifting the drill string.

| Direct Rotary                                                                                                  | Direct Rotary    |
|----------------------------------------------------------------------------------------------------------------|------------------|
| Type of Formation                                                                                              |                  |
| Direct Rotary                                                                                                  |                  |
| (with fluids)                                                                                                  | (with air)       |
|                                                                                                                |                  |
| Dune sand                                                                                                      | 5                |
|                                                                                                                |                  |
| Loose sand and gravel                                                                                          | 5                |
| Quicksand                                                                                                      | 5                |
| Loose boulders in alluvial                                                                                     |                  |
| fans or glacial drift                                                                                          | 21              |
| Clay and silt                                                                                                  | 5                |
| Firm shale                                                                                                     | 5                |
| Sticky shale                                                                                                   | 5                |
| Brittle shale                                                                                                  | 5                |
| Sandstonepoorly                                                                                               |                  |
| cemented                                                                                                       | 4                |
| Sandstonewell cemented                                                                                        | 3                |
| Chert nodules                                                                                                  | 3                |
| Limestone                                                                                                      | 5                |
| Limestone with chert                                                                                           |                  |
| nodules                                                                                                        | 3                |
| Limestone with small cracks                                                                                    |                  |
| or fractures                                                                                                   | 3                |
| Limestone, cavernous                                                                                           | 31              |
| Dolomite                                                                                                       | 5                |
| Basalts, thin layers in                                                                                        |                  |
| sedimentary rocks                                                                                              | 3                |
| Basaltsthick layers                                                                                           | 3                |
| Basaltshighly fractured                                                                                       |                  |
| (lost circulation zones)                                                                                       | 1                |
| Metamorphic rocks                                                                                              | 3                |
| Granite                                                                                                        | 3                |
| *Assuming sufficient hydrostatic pressure is available to contain active sand (under high confining pressures) |                  |
| Rate of Penetration:                                                                                           |                  |
| 1 Impossible                                                                                                   |                  |
| 2 Difficult                                                                                                    |                  |
| 3 Slow                                                                                                         |                  |
| 4 Medium                                                                                                       |                  |
| 5 Rapid                                                                                                        |                  |
| 6 Very Rapid                                                                                                   |                  |

d. *Mud Pump*. A mud pump (see Figure 4-2) on a rotary drill is usually a positive-displacement, doubleacting piston pump with capacities ranging from one to several hundred gpm at pressures up to several hundred pounds per square inch (psi). Power may be provided through a mechanical PTO and clutch,
with or without a separate transmission. Power may also be provided by a separate engine or a
hydraulic or air motor. Other types of pumps are used successfully, but their limited pressure capacity
may jeopardize the success of the drilling operation (i.e., pump capacity (volume and pressure) can limit the effective depth of a drilling operation). The horsepower required to drive a mud pump often
exceeds the power required to hoist and rotate the drill string.
e. *Hoists*. Man drill-head hoists (draw works) are mechanically or hydraulically driven wire-line winches.
On top-head rigs, the pulldown chains are used as the main hoist. Many drill rigs have auxiliary hoists for handling pipe, bailing, and for other equipment. The bailing drum usually has less lifting capacity
and a faster spooling rate than hoisting drums. Bailing drums can spool several hundred ft of wire line, which is sufficient to reach the bottom of most wells. Auxiliary hoists may be powered mechanically or hydraulically.
2. *Drill Bits*. Figure 4-3 illustrates rotating speeds for all sizes and types of bits in various formations. Figure
4-4 is a guide for bit selection.
a. *Tricone Roller Bits*. These bits are best suited for brittle or friable materials. The tricone bit consists of
three cone-shaped rollers with steel teeth milled into the surfaces. Tooth locations are designed so that
as the cone rotates, each tooth strikes the bottom of the hole at a different location. Drilling fluid is jetted on each roller to clean and cool it. The cutting action is a progressive crushing under the point
load of each tooth. Roller bits designed for rock, rocky soil (gravel), and soft formations (shale) have long teeth. The bits for harder formations have smaller, stronger teeth. The gauge teeth on bits designed
for very hard rock are reinforced with webs. For extremely hard formations, milled teeth are replaced with connected carbide buttons.
b. *Drag Bits*. These bits are used in soil and other unconsolidated materials. The blades are designed so
that they cut into the formation with a carving or scraping action. Drag bits may have multi-blade, hardened-steel, finger-shaped teeth or may have connected carbide-reinforced cutting edges.

Remove all jewelry and loose clothing before starting rotary drilling OPS.

3. *Rotary Operation.* Standard rotary drilling involves the bit rotating against the formation. Drilling fluid is
pumped through the drill string and face of the drill bit and backup the annulus to the surface. The rotary action of the bit loosens the material, while the drilling fluid cools and lubricates the drill pipe and bit and
carries cuttings to the surface. The drilling fluid is under high hydrostatic pressure and supports the wall
of the borehole against caving. The properties of the drilling fluid are important to the drilling operation.
Well drillers must have knowledge of drilling fluids and their use for successful rotary drilling. Drillers must also know about drilling-fluid additives used to prevent problems in drilling. Preventing drilling
problems, such as an unstable borehole wall or a stuck tool, is easier than fixing the problem after it
occurs. Refer to Paragraph 4.1, item 5 for additional details on drilling fluids. Before drilling with mud, build either a portable or an excavated mud pit. The decision depends on the hole depth and the alternatives available. Refer to Paragraph 4.1, item 5 for additional details on mud pits.

|                                                                                                                        | Medium          | Very Hard    |
|------------------------------------------------------------------------------------------------------------------------|-----------------|--------------|
| Soft                                                                                                                   | Hard            | Sandstones,  |
| Sticky                                                                                                                 |                 |              |
| Unconsolidated                                                                                                         |                 |              |
| Medium Hard                                                                                                            |                 |              |
| Sandstones,                                                                                                            | Bit Sizes       |              |
| and Types                                                                                                              | Shales, Silts,  | Hard Very    |
| Quartzite,                                                                                                             |                 |              |
| Angular                                                                                                                |                 |              |
| Shales or                                                                                                              |                 |              |
| Gumbos                                                                                                                 |                 |              |
| Hard Brittle                                                                                                           |                 |              |
| Shale and                                                                                                              |                 |              |
| Limestone                                                                                                              |                 |              |
| Conchoidal                                                                                                             |                 |              |
| Sandy Shales, etc.                                                                                                     |                 |              |
| Shales,                                                                                                                |                 |              |
| Sandy                                                                                                                  |                 |              |
| Shales,                                                                                                                | Sandy Shale     | Limestones,  |
| Fracture                                                                                                               |                 |              |
| Soft Chalk                                                                                                             | Anhydrite       |              |
| 13 to 20 inch                                                                                                          |                 |              |
| Drag                                                                                                                   | 100130         | 100130      |
| Zublin                                                                                                                 | 100160         | 100150      |
| Rock                                                                                                                   |                 |              |
| (rolling                                                                                                               |                 |              |
| cutter)                                                                                                                |                 | 125200      |
| 10 to 13 inch                                                                                                          |                 |              |
| Drag                                                                                                                   | 100175         | 100300      |
| Disc                                                                                                                   |                 | 110180      |
| Zublin                                                                                                                 | 125175         | 125200      |
| Rock                                                                                                                   |                 |              |
| (rolling                                                                                                               |                 |              |
| cutter)                                                                                                                |                 | 150300      |
| 6 to 10 inch                                                                                                           |                 |              |
| Drag                                                                                                                   | 125200         | 100200      |
| Zublin                                                                                                                 | 150200         | 100150      |
| Rock                                                                                                                   |                 |              |
| (rolling                                                                                                               |                 |              |
| cutter)                                                                                                                |                 | 150300      |
| The minimum speeds given are for flat lying strata and certain type bits. The maximum speeds are for flat or inclined  |                 |              |
| formations. The maximum allowable weight may be carried in flat beds and the minimum in steeply dipping strata. Slower |                 |              |
| and faster speeds than these recommended are useful in specific and more or less unusual cases.                        | (Brantly, 1961) |              |

4. *Variables.* Bit design, weight on bit, rotation speed, fluid consistency, cumulation pressure, and velocity
affect rotary drilling. Since experience helps drillers handle unique problems and conditions,
experimentation may help develop the best drilling procedure. Before starting the hole, plumb the kelly to
provide a straight hole (see Figure 4-5). The rig may be out of level as long is the kelly is straight.
a. *Bit Design*. Rotary drill bits are designed to cut specific material types. Choose the drill bit based on
the anticipated formation. Either drag or rotary bits may be available at a drill site. Normally, a drag bit is used to begin a borehole in unconsolidated overburden materials. These bits are used for hard,
medium, and soft rock and are part of the drilling-rig equipment. When drilling in soft rock, use a medium soft-rock drill bit. In very hard rock, stop mud rotary drilling; install casing to the rock layers, and use a down-hole air hammer. The objective is to produce a hole quickly and efficiently, but care
must be taken to not penetrate too quickly. Serious problems such as the drill string sticking in the hole,
excessive completion delays, equipment damage, and loss of the hole may occur by producing cuttings faster than that removed.
b. *Weight on Bit*. Adding weight on the bit increases the torque required for rotation. Too much weight
can cause excessive penetration and produce cuttings that are too large and heavy. Large cuttings are
difficult to wash out and may cause gumming and premature failure of the bit. Insufficient weight reduces or stops penetration and can produce fine cuttings. In cohesive soils, fine cuttings may thicken
the drilling fluid and fail to settle in the mud pit. How weight is applied can also cause serious alignment problems and difficulty in well construction. Rotary-drilled boreholes spiral slightly and are
seldom straight. Once spindling occurs, weight added by pulling down with the drill rig bends the string and magnifies the deviation. As such, the chain pulldown should never be used to advance the
hole beyond the first run (20 ft). Ideally, the drill string should be kept in tension by adding drill collars
(heavy wall drill steel) at the bottom just above the bit. Figure 4-6 provides drill collar weights.

Bore of Collar (in)
Collar
OD (in)
1 1/2
1 3/4
2
2 1/4
2 1/2
2 13/16
3
3 1/4
3 1/2
3 3/4
4
22.2
24.5 29.3 31.9
29.4
26.5


24.4
26.7 31.5 34.0
3 3/8
3 1/2 3 3/4 3 7/8
29.2 31.9 34.7 40.5 46.7
43.5


32.0 34.7 37.5 43.3 49.5
34.5 37.2 40.0 45.8 52.0
35.7 39.4 42.2 48.0 54.2
4
4 1/8 4 1/4 4 1/2 4 3/4
53.3 60.5
67.9
56.7
64.1


49.9 56.8 63.9
71.5
53.1 59.9 67.2
74.6
55.9 62.8 69.9
77.5
58.5 65.3 72.5
79.9
60.1 67.5 74.7
82.1
5
5 1/4 5 1/2
5 3/4
63.3 71.5 79.9 88.8


67.8 75.9 84.5 93.3
71.9 80.1 88.6 97.5
75.8 83.9 92.5
101.3
79.3 87.5 95.9
104.8
82.5 90.6 99.1
107.9
85.3 93.5
101.9 110.8
87.8 95.9
104.5 113.3
89.9 98.1
106.6 115.5
6
6 1/4 6 1/2 6 3/4
87.9 97.5
107.3 117.5
93.1
102.6 112.5 122.6
97.9
107.5 117.3 127.5
102.5 111.9 121.8 131.9
106.6 116.1 125.9 136.1
110.5 119.9 129.8 139.9
113.9 123.5 133.3 143.5
117.1 126.6 136.5 146.6
119.9 129.5 139.3 149.5
122.5 131.9 141.7 151.9
124.6 134.1 143.9 154.1
7
7 1/4 7 1/2 7 3/4
127.9 138.8 149.9 161.5
133.1 143.9 155.1 166.6
137.9 148.8 159.9 171.4
142.5 153.3 164.5 175.9
146.6 157.5 172.5 180.1
150.5 161.3 168.6 183.9
153.9 164.8 175.9 187.4
157.1 167.9 179.1 190.6
159.9 170.8 181.9 193.9
162.5 173.3 184.4 195.9
164.6 175.4 186.6 198.1
8
8 1/4 8 1/2 8 3/4
9
9 1/2

207.8 232.4
205.3 229.9
202.4 227.1
199.3 223.9
195.8 220.4
191.9 216.6
187.8 212.4
183.3 207.9
178.5 203.1
173.3 197.9
10
10 1/2


255.9 283.3
253.1 280.4
249.9 277.3
246.4 273.8
242.6 269.9
238.4 265.8
233.9 261.3
229.1 256.4
223.9 251.3
11


305.9
302.4
298.6
294.4
289.9
285.1
279.9
(Joy, 1978)


Use the pulldown feature on the drill rig as a last resort for short distances in hard strata.

  Bit weight required to cut rock depends on the design of the bit and the strength of the rock. Roller bits
need a minimum of 2,000 psi of bit diameter for soft rock and shale and a maximum of 6,000 psi of bit
diameter for hard rock. Before drilling, add drill collars instead of drill pipe until the load is sufficient for reasonable cutting. The drill string may have to be held back in order to add drill pipe as digging proceeds. Figure 4-7 provides weight on bit and rotary speed recommendations.
c. *Drill Steel*. Drill rods, collars, stabilize, subs, and bits are available in different sizes and materials. In
most drilling systems, drill rods are either steel or aluminum and come in lengths of either 5 or 20 ft.
d. *Rotation Speed*. Rotation speed is determined by the weight on the bit and the material being drilled.
The speed must be regulated to produce the correct size cuttings, which is derived from experience.
e. *Fluid Requirements*. Fluid requirements depend on size, weight, nature of cuttings, and circulation
velocity. Velocity depends on capacity and condition of the mud pump, annular area in the borehole,
and the stability and permeability of the formation. Refer to Paragraph 5 for additional details on
drilling fluids. Use the following formula and Figure 4-8 to determine the time required to evacuate
cuttings from the borehole.
AS Q = gpm  of pump  x 24.5 AS =  D2 -  d2
T=Q/HD where: Q= uphole velocity, in feet per minute (fpm)
AS= annular space, in square inches D = bore hole diameter, in inches d = drill string collar diameter, in inches. HD= hole depth, in feet T= evacuation time, in minutes


Weight per in/cm of Bit Diameter
Rotary Speed
Bit Classification
(rpm)
lb/in
kg/cm
Soft formation
3,400 to 6,750 4,050 to 7,800
609 to 1,210 725 to 1,400
250 to 100
180 to 60
Medium formation
4,500 to 9,000
806 to 1,610
120 to 40
Hard milled tooth bit
5,600 to 11,250
1,000 to 2,010
70 to 35
Hard insert bit
2,250 to 5,600 4,500 to 9,000
403 to 1,000 806 to 1,610
70 to 35 65 to 35
Hard friction bearing bit
4,500 to 6,750
806 to 1,210
60 to 35
(Ingersoll-Rand)

f. *Circulation Pressure and Velocity*. These elements of the drilling fluid are controlled by the pump
capacity and speed. The fluid's density, velocity, and viscosity let it carry cuttings. If the drilling fluid is too thick, cuttings will not settle in the mud pit. Sufficient velocity with a fluid of low viscosity (even water) carries drill cuttings to the surface. Excessive velocity erodes the wall of the hole to the
extent of failure.
  Pump pressure results from flow resistance caused by viscosity, friction, weight of the fluid column, or
restrictions in the circulating system. Pressure should be exerted at the ports in the bit, causing a downward jetting as the fluid exits. Regulate mud-pump pressure by varying the revolutions per minute (rpm) of the pump. Mud-pump pressure against the bit is not harmful if it does not exceed the operating pressure of the pump. Other sources of fluid pressure can be detrimental. Pressure from friction occurs
if the drill string is long for its inside diameter (ID) or pipes are internally upset. Frictional pressure
increases wear in the pump. Pressure from the weight of the fluid column in the annulus or from a restriction in the annulus caused by an accumulation of cuttings indicates insufficient cleaning. This
type of pressure can cause formation damage, resulting in lost circulation and wall damage.
g. *Stabilizers*. Unless the drill string includes stabilizers (see Figure 4-9) for large drill bits, drill a pilot
hole, using drill collars as stabilizers. The initial pilot hole (6-to 7 1/8-inch diameter) will be straighter and easier to sample. The location of aquifers will also be easier to determine. Use a larger bit to ream
the hole to the desired size. Use overreaming bits, if available, because they follow the pilot hole best.
5. *Drilling Fluids*. Drilling fluid is circulated in rotary drilling to cool, clean, and lubricate the drill string, to
flush cuttings from the hole, and to stabilize the borehole wall. Water is the basic fluid and is satisfactory
for lubricating and cooling the tools. However, water has limited abilities to carry cuttings and stabilize the borehole wall. Many drilling fluid additives are prepared and formulated for various purposes.
Polymer fluids and water-based clay fluids (muds) are the primary additives used in water-well drilling. Figure 4-10 lists drilling fluids.
  Mud cools and lubricates through heat absorption from the bit and reduction of drill-string abrasion
against the borehole wall. Heat is generated as the bit scrapes and grinds. Without the cooling fluid, the bit would overheat and be useless. Research indicates that removing the cuttings around and under the bit is the most important factor in keeping the bit cool. Requirements for cooling fluid are less than those for removing the cuttings.
  Therefore, by keeping the borehole clean with the fluid while drilling the bit is also cooled and lubricated.
This is true with clay muds and polymer fluids. Clay muds are colloidal suspensions. Solutions are
chemical mixtures that cannot be separated by simple filtering. Suspensions are physical mixtures of
solids and liquid that may separate during filtering. This distinction underlies the difference in behavior between drilling polymers (solutions) and drilling muds (suspensions). Natural clays can also be mixed
with water for use as a drilling mud since its properties are marginal for good water-well drilling.
  Hydrostatic pressure allows the fluid to support the borehole wall and is a function of the density or
weight of the mud column. Important characteristics of a drilling mud are viscosity and weight to carry cuttings, gel strength, yield point, and active clay solids for filter cake. Use the following formula to
calculate hydrostatic pressure:
Hp= (Md)(d)(0.052)
where:
Hp =  hydrostatic pressure, in psi.

Md= mud density, in lb per gallon. d=  hole depth, in ft

  For example, the hydrostatic pressure of a 200-foot hole with a mud weight of 9 lbs is as follows: 9 ft x
200 ft x 0.052 = 93.6 psi.

| Description                                                 | Baroid                                                                                | Primary Application                                                               |
|-------------------------------------------------------------|---------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------|
| Bentonite                                                   | Aqualgel                                                                              | Viscosity and filtration control in water-based drilling fluids                   |
| Sub-bentonite                                               | Baroco                                                                                | For use when larger particle size is desired for viscosity and filtration control |
| Attapulgite                                                 | Zeogel                                                                                | Viscosifier in saltwater drilling fluids                                          |
| Beneficiated                                                |                                                                                       |                                                                                   |
| bentonite                                                   |                                                                                       |                                                                                   |
| Quik-Gel                                                    | Quick viscosity in fresh water with minimum chemical treatment                        |                                                                                   |
| Polymers                                                    |                                                                                       |                                                                                   |
| Natural organic                                             |                                                                                       |                                                                                   |
| polymer                                                     |                                                                                       |                                                                                   |
|                                                             | Lightweight, low-solids drilling fluid for viscosity and filtration control in water- |                                                                                   |
| based drilling fluids                                       |                                                                                       |                                                                                   |
| Synthetic organic                                           |                                                                                       |                                                                                   |
| polymer                                                     |                                                                                       |                                                                                   |
| E-Z Mud                                                     | Lightweight, low-solids drilling fluid for viscosity and filtration control in water- |                                                                                   |
| based drilling fluids made with bentonitic additives        |                                                                                       |                                                                                   |
| Foaming Agents                                              |                                                                                       |                                                                                   |
| Foaming agents                                              | Quik-Foam                                                                             | Used in air drilling to increase hole-cleaning capability and reduce compressor   |
| requirements for a given depth or rate of water inflow      |                                                                                       |                                                                                   |
| Barafos                                                     | Thinner for freshwater drilling fluids with clay additives                            | Sodium                                                                            |
| tripolyphosphate                                            |                                                                                       |                                                                                   |
| (NA                                                         |                                                                                       |                                                                                   |
| 5                                                           |                                                                                       |                                                                                   |
| P                                                           |                                                                                       |                                                                                   |
| 3                                                           |                                                                                       |                                                                                   |
| O                                                           |                                                                                       |                                                                                   |
| 10                                                          |                                                                                       |                                                                                   |
| )                                                           |                                                                                       |                                                                                   |
| SAPP                                                        | For treating cement contamination in drilling fluids made with clay additives*        | Sodium acid pyro-                                                                 |
| phosphate                                                   |                                                                                       |                                                                                   |
| (Na                                                         |                                                                                       |                                                                                   |
| 2                                                           |                                                                                       |                                                                                   |
| H                                                           |                                                                                       |                                                                                   |
| 2                                                           |                                                                                       |                                                                                   |
| P                                                           |                                                                                       |                                                                                   |
| 2                                                           |                                                                                       |                                                                                   |
| O                                                           |                                                                                       |                                                                                   |
| 7                                                           |                                                                                       |                                                                                   |
| )                                                           |                                                                                       |                                                                                   |
| Detergents                                                  |                                                                                       |                                                                                   |
| Detergent                                                   | CON DET                                                                               | Used in water-based drilling fluids made with clay additives to aid in dropping   |
| sand; a detergent reduces torque and minimizes bit balling. |                                                                                       |                                                                                   |
| Bactericides                                                |                                                                                       |                                                                                   |
| Paraformaldehyde                                            | Aldacide                                                                              | Prevents organic additives from degradation                                       |
| Commercial Chemicals                                        |                                                                                       |                                                                                   |
| Sodium hydroxide                                            |                                                                                       |                                                                                   |
| (NaOH)                                                      |                                                                                       |                                                                                   |
| Caustic                                                     |                                                                                       |                                                                                   |
| soda                                                        |                                                                                       |                                                                                   |
| For pH control in water-based drilling fluids               |                                                                                       |                                                                                   |
| Sodium chloride                                             |                                                                                       |                                                                                   |
| (NaCl)                                                      |                                                                                       |                                                                                   |
| Salt                                                        | For solution weighting of water-based drilling fluids made with polymeric additives   |                                                                                   |
| Calcium chloride                                            |                                                                                       |                                                                                   |
| (CaCl                                                       |                                                                                       |                                                                                   |
| 2                                                           |                                                                                       |                                                                                   |
| )                                                           |                                                                                       |                                                                                   |
| Salt                                                        | For solution weighting of water-based drilling fluids made with polymeric additives   |                                                                                   |

*Also used for development of wells drilled with bentonite additives.

a. *Polymers*. Polymer fluids are water-based and very low in solids. Polymer admixtures are organic, inorganic,
natural, synthetic, or synthetically formulated natural polymers. Polymer additives are formulated for various drilling-fluid purposes and are used alone or to enhance clay muds. Polymers, containing salt and other contaminants, are available and are compatible with water. Polymers are more sensitive to pH than are
bentonite muds. Change the pH to effect desirable changes in the polymer fluid. Drilling-fluid weight
impacts drilling rate and high-density drilling fluid reduces drilling rate. There is strong indication that the
solids of a fluid have a similar effect as density. Polymer fluids are very different from clay muds because a large part of the polymer is soluble in water and becomes a solution when mixed with water. Long,
complicated molecular chains tie up the water and can build viscosity without solids. In water-well drilling,
many polymers are manufactured for producing drilling fluids, such as E-Z Mud, Revert, and Poly-Sal. E-Z Mud is a synthetic, inorganic polymer. Revert is a natural, organic polymer fluid derived from a guar plant.
  Polymers are generally best mixed through a mud gun. Polymers used for special purposes are available
from the manufacturer complete with specifics on how to use the product. Most polymers can hydrate
more water than a high-grade bentonite. Up to ten times more bentonite is needed to build the same
viscosity in a given amount of fluid, depending on the quality of the polymer. A polymer does not fully hydrate as quickly as bentonite. Mix the polymer very slowly through the mud gun a minimum of four
hours before using for more complete hydration. The fluid will thicken as hydration continues, so do not mix to the desired viscosity. Some polymers possess physical qualities that can result in unusual
hydration, gelling, and viscosity. Follow the manufacturer's recommendations for hydration. Factors that affect the viscosity are quality of polymer, concentration and size of colloid, metallic ions in mixing water, temperature, rate of shear, and pH.

  Water is the primary building block for drilling fluids. Water quality affects the overall performance of
drilling fluids. The action of bentonite in water is seriously impaired by dissolved acids or salty
substances. Acidic water usually contains dissolved metals that cannot be used unless treated. Hard water affects the suspending and sealing qualities of bentonite. The pH level is tested by using paper pH strips. The pH level should be 8 to 9. If the water is too acidic, treat it with soda ash at a ratio of 1
to 5 lbs of soda ash per 100 gallons of water. Following treatment, retest the pH level as before.
  Do not use water from wetlands, swamps, or small ponds for mixing drilling fluids because the water
may be contaminated. If these locations are the only source available, chlorinate the water before
making the drilling fluid. Be careful because chlorine removes metallic ions that are necessary for viscosity in polymers. Adjust the pH of drilling water to 8.59.5.
  Temperature affects the viscosity and stability of some polymers. Consider the following examples:
(1) Seven lb of Revert per 100 gallons of water at 45 F yields Marsh funnel viscosity of 125 seconds
per quart. The same mix at 85 F yields 70 seconds per quart.
(2) A 0.87 weight mix of Revert at 68 F yields a viscosity above 90 seconds per quart for three and a half
days. The same mix at 80 F maintains viscosity of 80 seconds per quart for only two days.
  Polymer drilling fluids can break down viscosity. Without treatment, the viscosity of some polymers (Revert)
completely breaks down in one to six days depending mainly on temperature; which is avoided by adding chlorine. Revert requires Fast Break; E-Z Mud needs sodium hypochlorite at a ratio of 2 quarts for every 100
gallons of water. Other polymers, such as E-Z Mud and Poly-Sal, maintain their viscosity for long periods of
time since natural breakdown is not significant. Figure 4-11 lists additives for drilling fluids.
  Polymer drilling fluids have virtually no gel strength because the colloids are nonionic and exhibit no
attraction for each other. Most of the drill cuttings should be washed out of the borehole before circulation is
stopped. A polymer fluid does not have thixotropic properties to hold cuttings in suspension. Shakers, desanders, or desilters are not needed when using polymer fluids. Since most of the cuttings are dropped out,
friction and wear in the pump are minimized and the drilling rate is not impeded by cuttings or high density.
A major advantage of polymers is the lack of mechanical wear to the drill-rig mud system.
  Some drilled fines (clay, silt) circulate back down the hole. Recirculated solids are much less a problem
with polymer fluids than with clay fluids. Revert will not hydrate in water containing any appreciable
amount of borate. However, Borax can be used to produce a gel plug in hydrated guar-gum polymer. With a pH of 7.5, the borate cress-links the polymeric chains and forms a strong three-dimensional
molecular gel. If a strong gel plug is necessary to get through a lost circulation zone, mix 1 cup of
borax in 5 gallons of water and pour slowly into the pump section while pumping at idle speed. When
the berated fluid (stringy gelled mass) recirculates, stop pumping for one-half hour. Resuming normal drilling should be possible after wasting the borated fluid. Repeat the procedure, if necessary. Although
the polymer fluid is not thixotropic and has no gel strength, it thins somewhat while being pumped.
  Polymer fluids build a type of membrane on the wall different from clay mud. Unnatural clay particles
(bentonite) are not introduced into the hole. Since the polymer fluid is partly a thick solution, infiltration into the permeable wall is reduced. However, insoluble portions of some polymer colloids do exist. The insoluble and cuttings are surrounded with thick coatings that are more impermeable per
unit thickness than a bentonite filter cake. The insoluble and cuttings seal the wall of the hole with a thinner, less active layer. The impermeable layer performs the same function as the filter cake in clay
muds but does not restrict the annulus.

Additive/
Marsh
Funnel
Base Fluid
Concentration
Viscosity
(seconds)
Annular
Uphole
Velocity
(ft/min)
Water
None
26  0.5
100120
For normal drilling (sand, silt, and clay)
Water
Clay (high-grade bentonite)


Increases viscosity (lifting capacity) of water significantly
1525 lb/100 gal
3555
80120
For normal drilling conditions (sand, silt, and clay)
2540 lb/100 gal
5570
80120
For gravel and other coarse-grained, poorly
consolidated formations
3545 lb/100 gal
6575
80120
For excessive fluid losses
Water
Polymer (natural)


Increases viscosity (lifting capacity) of water significantly
4.0 lb/100 gal
3555
80120
For normal drilling conditions (sand, silt, and clay)
6.1 lb/100 gal
6575
80120
For gravel and other coarse-grained, poorly
consolidated formations
6.5 lb/100 gal
7585
80120
For excessive fluid losses


Cuttings should be removed from the annulus before the
pump is shut down because polymeric drilling fluids have very little gel strength.
Air
None
N/A
3,0005,000
Fast drilling and adequate cleaning of medium to fine
cuttings, but may be dust problems at the surface
4,5006,000
This range of annular uphole velocities is required for
the dual-wall method of drilling
Air
Water (air mist) 0.252.00 gpm
N/A
3,0005,000
Controls dust at the surface and is suitable for
formations that have limited entry of water
Air
Surfactant/water (air-foam)
Extends the lifting capacity of the compressor
N/A
501,000
12 qt/100 gal
(0.250.5% surfactant)
For light drilling; small water inflow; sticky clay, wet sand, fine gravel, hard rock; few drilling problems
23 qt/100 gal
0.50.75% surfactant)
For average drilling conditions; larger diameter, deeper holes; large cuttings; increasing volumes of water inflow
34 qt/100 gal
0.751% surfactant)
For difficult drilling; deep, large-diameter holes; large, heavy cuttings; sticky and incompetent formations; large water inflows

N/A
50100
Air
Surfactant/colloids/water (stiff
foam)
Greatly extends lifting capacity of the compressor
34 qt/100 gal
(0.751% surfactant) plus
36 lb polymer/100 gal or
3050 lb bentonite/100 gal
48 qt/100 gal
(12% surfactant) plus
36 lb polymer/100 gal or
3050 lb bentonite/100 gal

(Compiled partly from information presented in Imco Services, 1975; Magcobar, 1977; and Barold, 1980).

Observations
Injection rates of surfactant/water mixture:
Unconsolidated formations
310 gpm

Fractured rock
37   gpm

Solid rock
35   gpm
For difficult drilling; deep, large-diameter holes; large, heavy cuttings; sticky and incompetent formations; large water inflows
For extremely difficult drilling; large, deep holes; lost circulation; incompetent formations; excessive water inflows

  The colloids in the polymer fluid are nonionic, have no chemical interaction, and are easier to remove
in water-well development. When the viscosity of the fluid is broken, much of the cohesive function of the thin film becomes a water-like liquid and is washed out of the water well. Field testing of polymer fluids, using a falter press and a Marsh funnel, yields different results. The mud balance for measuring
fluid density does not change. Weighing of the polymer fluid is limited, but by adding sodium chloride
to the fluid the weight is increased up to about 10 lbs per gallon. The addition of heavy solids (ground barite) is ineffective because of the polymer fluid's lack of thixotropic qualities.
b. *Mud Products*. Commercially processed clays for drilling are bentonite and attapulgite. Bentonite is
superior except in brackish or salty water (use attapulgite in these waters). Bentonite forms naturally
from decomposition of volcanic ash when ground. Bentonite consists of aggregates of flat platelets in
face-to-face contact. Bentonite is mined in many states, but the best grade (Wyoming bentonite) is
mined only in Wyoming and South Dakota. Wyoming bentonite contains sodium montmorillonite (the
active part of the clay mineral) and is small in size, which is important in building viscosity.
  Mud drilling fluids should be mixed with a mud gun. When agitated and sheared with water, the
bentonite platelets absorb more than 25 times their own weight in water, separate, and swell. The amount of surface area wetted determines the ability of the particle to build viscosity. One ounce of
Wyoming bentonite dispersed in water has more surface area than five football fields. Interparticle
activity between platelets gives the mud its gel properties. The chemical composition of the mixing
water affects the ability of bentonite to develop desirable qualities. These qualities are manipulated by
adding small amounts of various chemicals.
c. *Mud Viscosity*. True viscosity is a term relating only to true (Newtonian) fluids, such as water, and is a
proportional constant between shear stress and shear rate in laminar flow. Drilling muds act differently in that the proportion between shear stress and shear rate is reduced when shear rate is increased. Drilling muds are thixotropic. The viscosity of a drilling mud refers to the thickness of the mud while flowing. Gel strength is the term used to describe the thickness of drilling mud at rest. Gel strength
develops over a short period of time.
  Yield point is the mud quality broadly included in viscosity. More stress (pump pressure) is needed to
cause the gelled drilling mud to start flowing than to sustain flow once the gel is broken. The stress required initiating shear or flow is the gel strength of the mud. The stress required to maintain shear is the viscosity. A higher yield strength is required with respect to the gel strength so the mud becomes
very thin in flow shear.
  The primary function of viscosity is to help lift drill cuttings from the borehole. Other mud
characteristics affecting lifting capacity are density, velocity, and flow patterns. Gel strength holds the cuttings in suspension at the bottom of the hole when circulation is stopped. The stress (hydraulic pressure) required to break the gel strength to initiate cumulation can be detrimental. Required bottomhole pressures can cause fracturing or opening of fractures in the formation, resulting in loss of drilling
fluid, formation damage, and borehole wall damage. Down-hole pressure required to continue
circulation depends on friction, density (or weight of fluid column), and viscosity of the mobilized
fluid. These pressures can also cause serious problems. Therefore, it is desirable to use a drilling mud
of relatively low density and viscosity, moderate gel strength, and high yield point relative to the gel
strength (a very thin fluid in circulation).
d. *Mud Testing*. A Marsh funnel (see Figure 4-12) is routinely used to give an indication of thickness or
apparent viscosity of drilling fluid. A Marsh funnel is 12 inches long and 6 inches in diameter and has a No. 12 mesh strainer and a 1,000-milliliter (ml) cone. The funnel has a 2-inch-long, calibrated, hardrubber orifice with an ID of 3/16 inch. The funnel's cup is marked with a capacity of 1,000 ml. Use the
following procedure when using a Baroid Marsh funnel:
(1) Hold or mount the funnel in an upright position, and place a finger over the hole.
(2) Pour the test sample, freshly taken from the mud system, through the screen in the top of the funnel
until the level touches the top of the screen.
(3) Immediately remove the finger from the outlet tube, and measure the number of seconds for a quart
of mud to flow into the measuring cup.
(4) Record time in seconds as funnel viscosity.
Calibration time for fresh water at 70 F is 26 seconds.

(5) The funnel viscosity measurement obtained is influenced considerably by the gelation rate of the
mud sample and its density. Because of these variations, the viscosity values obtained with a Marsh funnel cannot be correlated directly with other types of viscometers and/or rheometers. Graduated in cubic centimeters (cc) and fluid ounces, the 1,000-cc measuring cup is designed specifically for use with a Marsh funnel viscometer. A quart volume is clearly marked on the measuring cup.

 The desired mud consistency depends on many factors. The nature of the formations will dictate
mud qualities. However, all conditions will not be known before drilling is started. The inexperienced driller must be careful because mud with the correct thickness often is too thin;
although viscosity is adjusted by adding water or clay. A good range for drilling muds is 32 to 50 seconds per quart. Viscosity is influenced by mud density, hole size, pumping rate, drilling rate, pressure requirements, and geology. Considering the thixotropic qualities of drilling mud, a funnel viscosity of 100 seconds per quart may be no more viscous than a funnel viscosity of 50 seconds per quart if both fluids are in motion.
  Test readings are a useful indicator of changes in mud that might lead to problems. Therefore, conduct
Marsh-funnel tests before beginning OPS and record the findings. Take mud samples for each test from the
same location in the circulating system just before returning to the hole. The apparent viscosity of the drilling mud in motion affects carrying capacity, the pump pressure (hydrostatic down-hole pressure) required for circulation, and the ability to drop cuttings in the settling pit. These characteristics are also intrinsically involved with well hydraulics, density of mud, density and size of cuttings, and particle slip.
e. *Density*. The carrying capacity of a mud is affected by its density and the density of the drill cuttings. If
the cuttings are denser than the fluid, they descend. The magnitude of the difference in density, particle
size, and fluid viscosity affect the rate at which a particle descends. Particle slip denotes this downward movement through the fluid. Ignoring thixotropy, the actual downward particle slip is constant regardless of velocity of flow. However, when the upward velocity of fluid exceeds the downward
particle slip, the new movement of the particle is upward. Up-hole velocity plays a major role in determining the carrying capacity of the cumulating fluid. The practical limits of up-hole velocity depend on pump size and capacity, ID of the drill string, jet size in the bit, viscosity of the fluid, crosssectional area of the annulus, and stability of the borehole wall. Up-hole velocity is not as simple as the comparison of pump capacity, drill string ID, and annulus. Up-hole velocity is not a constant.

  The density of the drill fluid serves other purposes in rotary drilling. Heavy fluids can control (hold
down) formation pressures encountered in drilling. Heavy mud is built by adding a weighing material such as ground barite (specific gravity 4.25). Prepare drilling mud in excess of 20 lbs per gallon by
using barite. First, mix bentonite and water to build viscosity. Then, add finely ground barite so the mud will hold the barite in suspension. Use heavy drilling mud only when absolutely necessary to
control pressures since the muds have disadvantages. High-density mud increases pressure on the
formation by the weight of the fluid column. Figure 4-13 shows the nomograph for determining the
hydrostatic head produced by drilling fluids. The increased pressure is further increased by the pump pressure required to mobilize the fluid in circulation. The increased pressure can cause formation
damage and loss of circulation. In formations that are strong enough to withstand the pressures without being damaged, the drilling operation can still suffer.
  The pressures from the mud and the formation should be balanced so that the borehole bottom exposed to the
drill bit is near surface eruption from pore pressure. That balance makes the formation easy to fracture and
enhances the cutting rate. If the mud pressure is much lower than the formation pressure, instability occurs in
the borehole. If the mud pressure far exceeds the formation pressure, the cuttings may be suppressed and reground by the bit. The result of recutting reduces bit life and lowers drilling rate. Mud density is increased by drill cuttings; the mud rising in the hole is heavier than the mud returning to the hole.
  All cuttings should be removed from the drilling mud in the settling pits and not recirculated. Although
100 percent removal is unrealistic, well-designed mud pits and mechanical screens, desanders, and desilters materially aid in removing cuttings from the mud. Water weighs 8.34 lbs per gallon. Clean, low-solid bentonite mud can weigh 8.5 to 9.0 lbs per gallon; try to maintain that weight. Increasing
density of the mud during drilling indicates that the mud contains native solids. The drill's penetration rate could be exceeding the combined effort of the mud pit, desanders, and fluids to effectively separate solids from the drilling mud. To correct this problem, slow down the penetration rate and run the
desanders to remove the solids.
  The density or weight of the drilling mud is determined by using a mud balance. Fill the mud-balance
cup with mud, and place the inset lid in the cup. Excess mud is displaced through a hole in the lid. Clean the outside cup area, place the assembly on the center pivot, and balance it using sliding weight.
Read mud density as lbs per gallon and lbs per cubic ft. If the mud weight that enters and exits the drill hole is known, an evaluation of the efficiency of the mud pit and mechanical separators is achievable. It
is also possible to determine when to clean the mud pit and tell how well the mud is cleaning the hole.
If samples are only taken from one location, it should be from the return end of the pit.
f. *Filter Cake*. Filter cake consists of solids from the drilling mud deposited on the borehole wall as the
water phase is lost into the formation. Desirable properties are thinness and impermeability. Drilling
mud is a colloidal suspension that is separable by simple filtering. With the hole kept full of mud, the hydrostatic pressure inside usually exceeds the formation pressure. Occasionally, an artisan aquifer is
penetrated, with formation pressure higher than the hydrostatic in-hole pressure. When the borehole pressure is higher than the formation pressure, the drilling mud tends to penetrate more permeable formations. Solids from the mud filter out and deposits on the wall while the liquid phase of the mud (filtrate) enters the formation.
  Filter cake is compacted against the wall by the excess hydrostatic pressure in the borehole. If the
drilling mud is a well-conditioned bentonite and water mixture, most of the solids plastered against the wall become flat platelets of highly active clay. The filter cake is self-regulating based on its degree of
impermeability. As long as filtrate passes through, the filter cake continues to thicken. A thick cake detrimentally increases down-hole cumulating pressure by restricting the annulus, making it difficult to pull the drill string because of the physical size of the drill collars and bit. In deep and somewhat deviated holes, the danger of key seating increases. Because a thick filter cake is of a lower quality and depends on its thickness to be effective, it is more easily damaged and eroded. A thick filter cake may indicate that the fluid has a high percentage of native solids; requiring a cleaning of these solids from the mud before drilling progresses.
  A thin, highly impermeable filter cake bonds well to the wall and provides a surface for the hydrostatic pressures to act against to support the wall. Filtrate loss into the formation accounts for significant fluid loss, if the consistency of the drilling mud is not good. Good consistency does not necessarily mean thick; it has to do with the bentonite content and the quality of filter cake. If a permeable formation is encountered with pore spaces too large to be plugged by the fine bentonite particles, the drilling mud enters the formation. That mud loss takes the entire output of the mud pump. The drill cuttings being carried up the annulus is sometimes beneficial. The cuttings are coarser than the bentonite particles and may help bridge across formation pores. If this technique is used, maintain the normal drilling rate to supply the cuttings. Slow down the pumping rate to reduce pressure on the formation while bridging the open spaces. With sufficient bridging, a suitable filter cake follows, circulation is regained, and normal drilling OPS are resumed.

  In the field, the filtration properties and filter-cake thickness is tested using the filter-press kit. This kit
consists of a press with a mounted pressure gauge and a CO2 charging system that is used to simulate
the hydrostatic pressure inside a 200-foot hole. By placing a sample of drilling mud in the press and
charging the system, a filter cake is formed. The filter cake should be less than 2/32-inch thick.
g. *Salty Environment*. A high chloride content in the mixing water causes bentonite to react anomalously
or not react at all. The ground bentonite remains agitated; it does not disperse, hydrate, or swell. In salt water, bentonite is an inefficient clay additive for drilling mud. The dissolved salt is an electrolyte that
changes the interparticle activity of bentonite. If a sufficient amount of salt water is added to a fresh water and bentonite mud mixture, the dispersed platelets forms lumps. Viscosity and filtrate loss
increase and the mud's ability to build a thin, impermeable filter cake decreases.
  Attapulgite is often used for salty formations. The small particles produce a high surface-area-tovolume relationship and good viscosity building. Unlike bentonite, the particle shape is needle-like.
Viscosity building in attapulgite depends on the entanglement of these needles. The disorderly
arrangement of the particles accounts for the poor filtration qualities of attapulgite. The filter cake is more like a layer of strew or sticks. Attapulgite clay does not have the physical qualities to build a thin,
impermeable filter cake. If bentonite is first mixed in fresh water with salt water added as make-up water, the bentonite flocculates; that flocculation is reversed by chemical treatment.
h. *Well Hydraulics*. A basic understanding of well hydraulics is paramount. Fluid is pumped down the
drill string, out the ports in the bit, and up the annular space between the drill string and the wall. The fluid empties into the mud pit, through any mechanical solids separating equipment, and is picked up from the pit by the mud pump for recirculation. The system is intended as a conservation system.
Except for mud lost into the formation or where artisan water exceeding hydrostatic pressure flows into the hole, the return is largely complete and the mud-pit level does not change. Even if these systems are
in equilibrium, an understanding of the up-hole rearrangement of flow patterns is necessary.
  Fluids flow in two distinct patterns; laminar and turbulent. Laminar flow is orderly. The streamlines
remain distinct and the flow direction at every point remains unchanged with time. Turbulent flow is
disorderly. The flow lines and directions are confined and heterogeneously mixed. The type of flow depends on the cross-sectional area of the fluid course and the velocity, density, and viscosity of the
fluid. In water-well drilling, the cross-sectional area of the annulus is usually several times that of the ID of the drill string. Because of the increase in volume in the annular space, flow at the point the fluid
leaves the bit is turbulent. The fluid becomes laminar flow when it begins flowing up the annular space. The returning fluid velocity is slower and the drill fluid is denser and probably has more apparent viscosity, which affects the flow pattern. To clean the hole and carry the drill cuttings out, turbulent flow in the annulus is better.
  Picture the flow in the annulus as a series of nested tubes. Velocity varies as if these tubes were sliding
past one another while moving in the same direction. Flow near the wall and near the drill string is at a
slower rate than near the center. Cuttings near the center are vigorously lifted while cuttings near the
wall and drill string actually slip in a net fall. Rotation of the drill string changes the flow pattern near
the drill string and materially enhances particle lift.
  For example, when using a 3 1/2 -inch ID and 4-inch outside diameter (OD) pipe to drill a 9-inch hole
and pump 200 gpm, the velocity of the ID pipe is 400 fpm) and the velocity of the OD pipe is 75 fpm. To test cumulation at these rates (bit is 300 ft deep), pump down a marker (strew or oats). The majority
of the material should take four minutes and 45 seconds to return (300 ft at 400 fpm takes 45 seconds and 300 ft at 75 fpm takes four minutes). To clean all the cuttings from a 300-foot depth with an
average up-hole mud velocity of 75 fpm requires more than four minutes of pumping. Consider this concept regarding sampling cuttings from the return mud.
  If cuttings remain in the annular space between the drill rod and borehole wall when circulation is stopped,
they produce a denser fluid than the clean drilling mud inside the drill rods. The denser mud in the annular
space then flows down the hole and forces the clean drilling mud up the drill rods. This causes a geyser effect, and the drilling mud may shoot several ft into the air until the mud columns equalize (some drillers mistake this for a caving hole). If this situation happens when adding drill rods, increase the circulation time after drilling down the next rod. Use the following formula to calculate the annular space volume:

     2  2 =   1,000 d )(5.5)(L) (D V
   where: V = annular space volume, in cubic ft. D = hole diameter or bit size, in inches (refer to Figure 4-8) d = drill hole or drill steel collar diameter, in inches (refer to Figure 4-8)
   L = hole length, in ft (refer to Figure 4-8)

i. Mud Pits. Rotary chilling preparation is the design and excavation of an in-ground mud pit or installation of a
portable mud pit and the mixing of the drilling fluid. For standard drilling OPS that use well-completion kits,
well depths could range from 600 to 1,500 ft. For wells up to 600 ft using the 600-foot well drilling system
(WDS), use portable mud pits. For wells over 600 ft, use dug mud pits. In either case, clean the cuttings from the pits as drilling progresses. Design considerations include the anticipated depth and diameter of the drill
hole, since the material cuttings from the hole is deposited in the mud pits.
  The volume of the pits must equal the volume of the completed hole. Therefore, during drilling, clean
the cuttings from the pits frequently. The size and depth of the pits are not critical if a backhoe is on
site to dig and clean the pits. If pits are dug and cleaned with shovels, width and depth are important.
Drilled cuttings should drop out of suspension in the mud pit. Therefore, long, narrow pits are better.
Figure 4-14 shows a mud-pit layout and a chart depicting mud pit capacities and dimensions.
Portable mud pits require constant cleaning.

  Mud pits are part of the circulating system for mixing and storing drilling fluid and for settling cuttings.
The ground slope affects site layout. Pit design enhances pit performance. Most drillers agree using multiple pits is best when dropping drill cuttings from the fluid. The volume of the pit should be one and one-half to three times the volume of the hole. This provides fluid to fill the hole and an excess volume to allow stilling and settlement or processing before returning to the drill string. A volume of
three times the hole volume minimizes drilling-fluid and mud-pit maintenance. Figure 4-15 shows a mud pit that is prepared on-site. Figure 4-16 shows a portable mud pit.
  If drilling mud is processed through shale shakers, desanders, desilters, and space and time for cuttings
settlement are not important. Long, narrow pits connected at opposite ends by narrow, shallow trenches
are preferred. If using a polymer fluid that has no thixotropic qualities, the settlement of cuttings is a function of time at low velocity or no flow. With polymer fluid, a long-path mud pit is ideal; if part of
the flow almost stops, cutting settlement is enhanced.
  If a clay-based mud with thixotropic qualities is used and the mud moves slowly or flow stops, the gel
strength can hold the cuttings. High velocity through narrow, shallow trenches holds the cuttings in
suspension. If mud runs over one or more wide baffles or weirs, flow shear and velocity are low. These factors enhance cuttings to drop out. If mud processing equipment is available, use it. Recirculating
clean fluid reduces power requirements, wear, and erosion and enhances drilling rate.
1.
Rectangular Mud Pit
Volume (gal) = Length (ft) x Width (ft) x Depth (ft) x 7.5

2.
Pit with Slope Sides
Volume (gal) = Length (ft) x Average Width (ft) x Depth (ft) x 7.5

Average Width = Width at Top + Width at Bottom

3.
Ideal Dimensions for Two Basic Pits
In general, the pit should be three times the volume of the finished borehole. Each mud pit should have a settling section and a suction section. The dimensions of the settling pit are determined by using a basic equation to establish the width. Once the width is known, calculation of the length and depth is possible.

         3 2.125 x 7.5 hole volume (gal) x 2 Width =
where:


Length = 2.5 x Width

Depth  = 0.85 x Width
For the suction pit, the length is 1.25 x Width and the Depth is 0.85 x Width

6. *Rotary Drilling Problems*. Some problems in rotary drilling are minor and others are serious and result in
failure to complete a hole or even loss of equipment. Many serious problems start minor, but become
serious if not recognized or handled properly. For example, in a loose sand zone, the borehole walls can
slough and cause drilling fluid loss. By reducing or increasing fluid velocity, stabilization of the wall and regaining fluid circulation is possible. However, if the condition is not recognized and drilling continues, the wall will slough and create a cavity. The cuttings lose velocity, become suspended in the cavity, and
tend to fall back into the hole when rods are added; which may result in the rods or the bit becoming stuck
in the hole. Other problems may result from subtle changes in geology, imbalances in the drilling operation, or equipment failure.
a. *Lost Circulation*. Lost circulation refers to a loss in volume of drilling fluid returning to the surface.
The implication is that some fluid pumped down the drill pipe is entering the formations. The mud pit
may lower, since some of the mud is used in forming a mud cake on the borehole wall; however, increased lowering can indicate circulation loss. Losses may occur through open-graded sand or gravel or open joints in rock. A loss may occur when cuttings are not washed out and the borehole annulus
becomes restricted, resulting in increased down-hole pressure. Spudding (raising and lowering the drill
string) the hole too violently may cause loss. Spudding helps wash cuttings, but down-hole pressures
increase momentarily. Experienced drillers are able to estimate when spudding is safe. The driller is blind when fluid cumulation is lost and drilling continues. An experienced driller that knows the rig can often drill blind successfully, but reestablishing circulation is always safer.
  Reestablishing circulation involves one of several techniques. Commercial items such as chopped
paper, straw, cottonseed, and nut hulls may be added to the mud pit. Sometimes, while the loss zone is grouted and redrilled, the grout is lost into the formation. Commercial drilling additives such as a
polymer may be used to reduce fluid loss in some formations. In this situation, the casing may be set through the loss zone. Occasionally, drill cuttings plug the loss zone by reducing fluid velocity while continuing to drill. Reestablishing circulation is usually a trial-and-error process. The longer a drill is
without circulation the more difficult it is to reestablish circulation.
b. *Fall-In*. Fall-in is material that accumulates in the bottom of the borehole after cumulation is stopped.
This material is borehole-wall material that results from sloughing or caving or cuttings previously
carried in suspension. Fall-in occurs when a loose, unstable formation is encountered and the drillingfluid weight is insufficient to stabilize the formation. If a fall-in is suspected or anticipated, raise the drill bit off the bottom of the hole (20-foot minimum) each time drilling is interrupted. This prevents the cuttings and fall-in from settling back around the bit until the problem is solved.
c. *Stuck Drill String*. The drill bit and any collars just above the bit are larger in diameter than the drill
pipe. The string becomes stuck when cuttings collect on the bit and collar shoulder. This condition is called sanded in. Be careful because the drill pipe may break while trying to remove the drill string.
Regaining circulation and working the sand out are seldom successful. If the formation does not take
the fluid when the pump clutch is engaged, the relief (pop-off) valve operates to relieve the pressure. Not many actions will free the drill string except to wash a small pipe down the annulus to the bit and
jet the settled sand back into suspension. When the annulus is too small to pass a jet pipe, a part of the drill string may be lost.

Never try to stop the relief-valve operation to get higher pressure. Do not override the relief valve; it protects equipment and operators.

  When the annulus is small, excessive up-hole velocity promotes erosion of the filter cake in granular
zones and allows caving against the drill pipe. If this occurs, try to maintain circulation and rotation,

even if circulation is slight. Where the grains are angular, the drill pipe may become locked while being rotated. This situation is similar to a sanded-in bit. With smooth pipe (not upset), hammering up and down may sometimes dislodge the string; allowing the reestablishment of circulation and the continuing of drilling. Be careful because hammering up and down may produce unfavorable compacting of the sand. In a hole of fine-grained soil or shale, where the alignment has significantly deviated and the drill pipe has wallowed into the wall, the pipe may become wall stuck. Pipe friction and relatively high borehole pressure may move the pipe tighter into the wallowed groove as the string is pulled. An alert driller should recognize early stages of deviation and take measures to realign the hole.

d. *String Failure*. When the drill string parts, leaving a portion in the borehole (a fish), the drill string is
rung off. Attempting to retrieve the lost portion is known as fishing. Fishing tools include a tapered tap
and an overshot die (see Figure 4-17). Ringing off is normally fatigue failure in the drill-rod joints caused by excessive torque or thrust (repeated flexing and vibration that crystallizes heat-treated tool
joints) or by borehole deviation (with flexing of the string). Examine drill rods for signs of failure,
frequently.
e. *Deviation*. A deviated borehole is called going crooked. If the initial setup is made without plumbing
the kelly, the borehole will likely go crooked. A crooked borehole usually amplifies other problems and makes a borehole unsuitable for a well. However, always anticipate deviation since the borehole naturally tends to spiral from bit rotation. Variations in the formation badness may start deviation.
Excessive bit loads magnify minor initial deviation. Use all available guides and collars and a reduction in bit load to minimize deviation.
f. *Swelling Soil*. The in-hole effects of swelling soil (shale or clay) that absorbs water from the drilling
fluid is squeezing. The result is a borehole that is undergauged to the extent that pulling the bit by normal hoisting methods is not possible. In such cases, cutting through the blockage with a roller rockbit or a drag bit may resolve the issue. Swelling causes caving and failure of the wall. Keep water out
of the formation to prevent swelling. Special polymer drilling fluid additives that limit water absorption
are available. High quality bentonite forms a thin, but highly impermeable filter cake.

## 4.2 Air Rotary Drilling

Air rotary drilling is similar to mud rotary drilling except that the fluid circulated is compressed air. The air is not recirculated. Using compressed air is advantageous when water for drilling is inconvenient, fluid is being lost to the formation while drilling, or it is difficult to wash sticky clay formations from the hole. Also, air rotary drilling requires much less development time. However, air rotary techniques may need adjustment with each well drilled. Some disadvantages to air rotary drilling are that air cannot support the wall of a hole in an unstable formation, changes in the return air flow are not as readily apparent as in mud flow, and air is not as effective in cooling and lubricating the drill bit and string. The list below describes air rotary drilling in more detail:

1. *Air Supply*. Air has no density or viscosity, so cuttings are blown out of the hole at high velocity. The uphole air flow is turbulent and more effective in lifting the cuttings. The lack of density and viscosity increases the particle slip so a continuous and high velocity up-hole flow must be maintained to keep the hole clean. An upward velocity of about 4,000 fpm is sufficient to clean cuttings out of the hole. Cutting
removal also depends somewhat on size, density, and amount of cuttings. Up-hole air velocity is computed
by dividing the output volume of the air compressor, in cubic feet per minute (cfm), by the cross-sectional
area of the annulus of the hole, in ft. Air compressors are rated on the following items:
a. Intake air volume. b. Condition. Compressors wear with use, causing capacity to decrease.
c. Sea level. Output volume capacity is reduced about 3.5 percent for every 1,000 ft above sea level. d. Temperature. Efficiency is reduced when temperatures are above 60 F and is increased when
temperatures are below 60 F.
e. Rotation speed. Output from the compressor is directly proportional to the motor's rpm. Do not operate
a compressor at lower rpm to reduce wear.
  Dry material drilled by air creates a large amount of dust when blown from the borehole. Inject water to
control the dust. Depending on the nature of the material drilled, the amount of water could be 1/2 to 5 gpm. Water injection increases air density and improves carrying efficiency for the cuttings. Adversely,
water causes the cuttings to stick together, making them heavier and harder to blow out of the borehole, or
the cuttings may stick to the borehole wall, causing constriction.
  Minor wetting or dampening makes some walls more stable; excessive wetting causes a wall to fail.
Adjusting the amount of water injected into the borehole takes experience. Air has no wall-stabilizing
qualities. In soils where sloughing and caving are a problem, injection of a thin drilling mud (bentonite
mixed with the injection water) controls the dust and contributes to stability.
  In drilling large diameters (12-inches) with standard drill pipe (3 1/2 inches OD), the annulus equals 0.7 square
ft. Using a 1,000-cfm compressor the up-hole velocity would be about 1,400 fpm, which is not enough velocity
to remove cuttings. While penetration progresses, the cuttings tend to stay at the bottom of the borehole under
the drill bit and are recrushed. These cuttings act as a pad under the teeth of the bit and prevent proper cutting
action. The compressor normally cannot drill holes by straight air rotary.
  Use the following equations to estimate compressor size, up-hole velocity, and hole-size requirements for
air drilling or Figure 4-18 to determine up-hole velocity. The recommended up-hole velocities are: 3,000
fpm, minimum; 4,000 fpm, fair; and 5,000 fpm, good.
Vmin= (D2-d2)16.5  where:
Vmin = minimum velocity, in cfm. D       = hole diameter or bit size, in inches (refer to Figure 4-8).

d       = drill steel or drill collar in diameter in inches (refer to Figure 4-8). and Vmin C
V =

velocities are: 3,000 fpm, minimum; 4,000 fpm, fair; and 5,000 fpm, good. where:
V        = actual up-hole velocity, in fpm. C        = compressor capacity, in cfm. Vmin  = minimum velocity, in cfm.

  Air drilling has a depth limitation because of water in the borehole. Air pressure must displace the head of
water in the borehole before it can exit the bit. An advantage is that when water is encountered, it discharges with the air. As drilling progresses, an estimation of the amount of inflow to the well is possible. When calculating the static head of water, remember that 0.434 psi equals 1 foot of head or 1 psi equals 2.3 ft of water. For example, the minimum psi required to overcome a 400-foot static water-level
column is 173.6 psi (400 ft x 4.34 psi = 173.6 psi).
2. *Foamers*. Commercial foamers for drilling enhance the air's ability to carry cuttings and reduce the velocity
required to clean the borehole. The foamer is mixed with the injection water, but does not foam with gentle stirring; therefore, pumping is not hindered. Foam must be pumped at a pressure greater than the air-line
pressure into which it will be injected. The foaming and mixing with air largely occurs when exiting the drill bit.
If air flow is reduced from the volume required for air rotary drilling and the injection rate is tuned to the
airflow, the foam leaves the hole as a slow-moving mass (see Figure 4-19). The foam is laden with drill cuttings and the borehole is effectively cleaned with only 10 percent of the air volume required had foam not been used.
Boreholes of 2 ft or more in diameter are possible with a well-tuned air-foam operation using air compressors.
Figure 4-20 illustrates a list of common problems with air-foam systems.
  Commercial foamers vary and come with mixing instructions on the container. Only a few foamers are
necessary to produce large volumes of rich foam. Less than one quart of foamer mixed with 100 gallons of
water injected at a 2- to 3-gpm rate is sufficient for a 12-inch diameter borehole. The column of foam
provides slight stabilization to the wall. Increasing the richness and density of the foam is possible by mixing bentonite with the injection water before adding the foamer. A very thin fluid of 15 to 20 lbs of
bentonite mixed in 100 gallons of water is suitable for injection in air-foam drilling.
  Adding foamer to this fluid in the same proportions as clear water, results in richer, more stable foam.
This technique is sometimes called air-foam-gel drilling. The gel refers to the bentonite fraction. Because of the increased richness, stability, and density of the air-foam gel, the air's cutting-carrying capacity and
the wall stabilization are enhanced. Foam reaching the surface must be carried away from the drill rig to avoid mounding over the work area. Foam eventually dissipates when exposed to the atmosphere. Use
either of the following methods to remove the foam from the rig area:

| Problem                                 | Reason for Occurrence               |
|-----------------------------------------|-------------------------------------|
| Air blowing free at the blooey          |                                     |
| line with a fine mist of foam           |                                     |
| Air has broken through foam mix         |                                     |
| preventing stable foam formation        |                                     |
| Increase liquid injection rate or       |                                     |
| decrease air injection rate             |                                     |
| Foam thin and watery                    | Formation water entry with possible |
| salts contamination                     |                                     |
| Increase liquid and air injection       |                                     |
| rates, and possibly increase            |                                     |
| percent of foaming agent                |                                     |
| Quick pressure drop                     | Air has broken through foam mix     |
| preventing formation of stable foam     |                                     |
| Increase liquid injection rate or       |                                     |
| decrease air injection rate             |                                     |
| Slow, gradual pressure increase         | Increase in amount of cuttings or   |
| formation fluid being lifted to surface |                                     |
| Increase air injection rate slightly    |                                     |
| Quick pressure increase                 | Bit plugged or formation packed off |
| around drill pipe                       |                                     |
| Stop drilling and attempt to regain     |                                     |
| circulation by moving pipe              |                                     |

- Method 1. Use a packer to seal the top of the surface casing around the drill pipe or kelly bar so either
rotates freely. Fit the top of the surface casing with a T pipe below the packer for connecting a waste pipe. As foam comes out of the waste pipe, remove it from the rig.
- Method 2. Place a T pipe at the top of the casing with an air-line eductor that causes a vacuum at the top
of the hole. The foam is vacuumed into and blown through the waste pipe. By using an eductor, returning foam is observed and regulated. The eductor is fabricated and the drilling operation does not usually require the full output of the compressor.

## 4.3 Percussion Drilling

This type of drilling involves crushing by impact of the teeth of the drill bit. Most percussion drills are actuated by compressed air (pneumatic percussion). Essentially, percussion drilling for water wells uses down-hole, pneumaticpercussion hammer drills. Down-hole means the percussion motor (actuating device) is at the bottom of the drill string. Percussion drills are best suited for drilling brittle, moderately soft to hard rock. In hard rock with percussion drills, drilling is faster and more economical than with other drilling methods. The air blows the cuttings from under the bit and up the annulus to the surface. The air's ability to carry the rock chips depends primarily on high air velocity. An up-hole velocity of about 4,000 fpm is required to remove cuttings. If drill penetration rates are high (30 fpm or more), a higher up-hole velocity is needed to clean the hole. To drill water wells with percussion drills, balancing drill perimeters with the materials is paramount. Down-hole hammer drilling with a large diameter hammer or bit (see Figure 4-21) usually results in a very crooked hole unless drill stabilizers are used or the hole is drilled in two steps. For two-stage drilling, drill a small pilot borehole with a 6- to 6 1/2 -inch bit on a small hammer using drill collars as stabilizers. Enlarge the borehole using a stinger bit for drilling. The list below describes percussion drilling in more detail:

1. *Equipment*. Shallow holes for loading explosives in rock quarries and other excavations are usually drilled
by percussion. Percussion drills are used because they penetrate quickly, even through hard rock. Most
percussive motors or actuating devices are above ground. Top-head percussion drilling is not practical for
deep boreholes because too much energy is lost in the long drill string. The down-hole drill was developed
for efficiency. This drill is adaptable to most rigs and can drill water wells to depths exceeding 2,000 ft.
To operate the drill, hoist, handle, and rotate the drill string as well as the drill motor and have an adequate air supply. Supplementing the air supply with an auxiliary (tag-along) compressor is possible
when necessary through simple plumbing.
  During operation, an air-actuated piston impacts the drill-bit shank. Porting within the drill case forces the
piston up and down with the full force of the air pressure. The drill-bit shank is splined and is slide in the splines about 2 inches until fully extended. The bit is held in the drill by a retainer ring and may have
several design shapes. Currently, all down-hole bits are set with carbide buttons specifically formulated
for the percussion application. The carbide button bit is more durable than other bits made from hardened steel. However, the drill bit dulls and buttons flatten from wear. A dull bit is less efficient, works harder, is easily damaged, and has a reduced production rate.

  A green stone is able to reshape a flattened carbide button. An experienced operator recognizes excessive wear
and knows when to reshape the button. A percussion drill bit should drill 1,000 ft or more in hard rock without
reshaping. A properly maintained bit has the longest service life and drills the most economical holes. Sharpening and reshaping the carbide buttons are detailed procedures. See the manufacturer's service manual for these procedures. The object of reshaping the button is to restore the hemispherical shape without removing excessive carbide material. The cutting points on a reshaped bit are be about equal in length. The flat area of each button is symmetrical around the cutting point and each button wears equally, which makes reshaping simple. Marking the center of the flat with ink represents the original cutting point and is the same length from the bit body as the other buttons. Carefully grind the worn button to a round shape leaving a flat (1/16-inch
diameter) at the ink mark. Grind each button consistently; realizing that the reshaped buttons will not be perfect.
2. *Power*. Operating the down-hole drill is not difficult. Percussion drills are designed to operate at air
pressures of 150 to 350 psi. The percussion drill is an orifice that leaks air out of the system. Air passing through the percussion drill actuates the piston and exhausts into the hole. The air volume used to actuate the drill is consumed by the drill. As the air consumption of the percussion drill increases, the air pressure delivered to the drill increases (see Figure 4-22). For example, if a percussion drill consumes 150 cfm of air at 200 psi, a compressor that maintains 200 psi while losing 150 cfm of air to drill at 200 psi is needed.
   Compressors are positive displacement air pumps. Pressure is a function of chamber ratio and leakage within
the displacement mechanism. For example, a 200-psi compressor produces 200 psi in a closed receiver while turning a few rpm. The volume of air produced is a function of the displacement chamber, size of the cylinders or rotors, and the speed of rotation. Volume output is directly proportional to speed of rotation.
Efficiency of the compressor is adversely affected by wear within the compressor and the elevation and ambient temperature.
  Energy output from any drill is directly proportional to the air pressure delivered to the drill (see Figure 4-22).
The percussion drill reacts to a pressure differential between intake and exhaust. The pressure delivered to the
drill is somewhat less than the gauge pressure at the compressor because of friction loss in the plumbing; pressure in the borehole increases with depth because of friction and the load of cuttings and water. Increased pressure in the borehole reduces the effective pressure differential across the drill. The friction losses in
plumbing and pressure at the bottom of the hole are calculable, but the calculations are not very useful. When
drilling, the hammer is heard operating in the hole when it reaches the bottom. If the hammer fails to start operating, do not let the bit rotate on the bottom of the hole because it could destroy the buttons.

Free Air Consumption of Tool (scfm)
Choke Size
200
250
300
350
(inches)
150
(psig)
(psig)
(psig)
(psig)
(psig)
Blank
260
375
500
625
730
1/8
285
405
540
675
770
3/16
315
440
590
730
835
1/4
340
465
645
800
920
5/16
410
565
735
900
1,030
(none) 3/8
460
640
825
1,005
1,140

3. *Procedure*. Attach the percussion drill to the drill string or drill kelly and lower the drill until the drill sets on
the material. Extend the drill bit (open position) in the splines. If air is applied with the drill bit extended, the
air blows directly through the drill and the drill does not function (the piston is not actuated). Weight applied
on the drill must be sufficient to push the drill bit into the drill (closed position) while holding it closed. While maintaining the load, apply air pressure and slowly rotate the drill. When these actions are balanced, the drilling operation is optimal. Balance is attained by experimenting during drilling.
a. *Weight on Bit*. The weight applied to the drill must be sufficient to hold it in the closed position while
drilling. While the drill bit is splined and moves in relation to the drill, the bit should not move in the splines while drilling. The required weight on the bit (bit load) varies somewhat with percussion drills from different manufacture. With a given drill, the bit load varies with the air pressure used for drilling. The air pressure does not tend to enter the drill bit (open position), however, the energy with which the piston strikes the bit shank is directly proportional to the air pressure applied. Consequently, more bit load is necessary to keep the
bit in the closed position with higher air pressure. See the manufacturer's manual for specific
recommendations for minimum bit load. The range for a 6-inch drill generates about 2,500 lbs total bit load
at 125 psi to 4,000 lbs total bit load at 200 psi. Increasing bit load above the recommended minimum does little to increase the drilling rate. To achieve an increase in production rate, add weight if it does not adversely affect the rotation speed or constancy. Too much bit load will:
(1) Affect the constancy of the rotation, which is detrimental to drilling production rate.
(2) Damage the drill. (3) Cause excessive wear and premature failure of the bit.
b. *Plumbness*. Water wells should be plumb and straight. Apply bit load by using drill collars to hold the
drill string in tension. Most rigs have a mechanism designed for that purpose. Because the drill string is relatively flexible, loads applied from the top cause the drill string to flex and may misalign the drill bit. This procedure causes the drill to deviate from vertical and continued top loading exaggerates deviation. Apply bit load by adding heavy drill pipe sections (drill collars) at the bottom of the drill string just above the bit. If a sufficient load is added at the bottom, the drill string is held in tension while drilling. The borehole tends to be straight because of the pendulum effect. Borehole deviations
from vertical are sometimes associated with fast drilling rates. Such deviations actually result from crowding the bit (trying to increase the penetration rate by overloading the bit).
c. *Air Pressure*. Exceeding the 350-psi rating of the drill is not possible with the supplied compressors. The
energy output of the drill is proportional to the air pressure delivered. Try to operate the drill at the maximum
air pressure available. Lubricate the drill, using an in-line oiler designed for operation at the maximum anticipated working pressure. To control dust, inject a small amount of water into the airline. The injection pump and plumbing are extremely dangerous if failure occurs because they are subjected to maximum
pressure.
Do not exceed the maximum air-pressure ratings of percussion drills.


Rapid expansion of compressed air from bursting hoses and loose connections may cause injury. Only use replacement parts in the air system that the appropriate technical manuals recommend.

d. *Rotation*. As drilling progresses, adjust the bit rotation to the penetration rate. As the hole deepens, the
bit should make one revolution equal to the length of exposure of the carbide buttons in the bit (about
1/3-inch). The rule of thumb is that the rotation rate (in rpm) should approximately equal the penetration rate in feet per hour. The rotation rate for percussion drilling is slower than for rotary
drilling. For percussion drilling to function at maximum proficiency, the rotation must be constant. As the piston strikes the bit shank (about 1,200 blows per minute at maximum air pressure), the constant rotation allows the bit buttons to chip continuously at new rock. If the rotation rate is not constant (stops and jumps), the buttons hammer several times in one place before jumping to new rock. Erratic rotation produces variable sized chips, which are harder to clean from the hole. Erratic rotation also causes the buttons to penetrate too deep, increasing drag on rotation and excessive wear and button breakage.
  There are two main causes for erratic rotation; hydraulic top-head-drives and borehole wall friction.
Top-head-drive rigs rotate the drill string with a hydraulic motor. Even when tremendous torque is
applied, a hydraulic system does not produce positive movement and reacts to drag or resistance to
cause drill string rotation. The hydraulic top-head-drive rig is highly susceptible to erratic rotation. The primary force resisting rotation is weight on the bit. If this weight is excessive, the hydraulic drive produces a series of pressure variations and the bit rotates in a sequence of starts and stops. Even with
mechanical drive rotation, which is nearly a positive movement, drag on the drill bit causes twist in the drill string, resulting in erratic rotation of the bit. This occurrence is more pronounced in deep holes.
  The secondary cause of erratic rotation is borehole wall friction. All friction between the borehole wall
and the drill string cannot be eliminated. The more a borehole deviates, from being straight, the greater
the friction. It is easy to visualize a distorted drill string caused by excessive top loading and how the distortion causes increased borehole wall friction. Other contributors to borehole wall frictional are
rock abusiveness, poor lubrication of the drill string (injected or natural-water condition), and poor
cutting removal.
4. *Adjusting to Variables*. Economical and satisfactory drilling, using the down-hole percussion drill,
requires fine tuning of the variables. Efficiency is directly proportional to the air pressure delivered to the drill. Operating at the maximum air pressure should be the constant. The bit load, ideally a bottom string
load, should exceed the maximum load required for the drill in order for the load to be properly adjusted by increasing hold back with the drill rig. Do not overload the bottom string because the drill string weight
increases as the depth increases. Do not overload the hoisting capacity of the rig. Adjust the rotation speed to the penetration rate and use the constancy of the rotation to regulate weight on the bit.
  Air blows the rock chips from under the drill bit on up the annulus to the surface. Since air has no
effective viscosity or density to float the chips, removal is a function of the velocity of the returning air. A minimum velocity of 3,000 to 4,000 fpm is necessary. Larger diameter drill pipe reduces the area of the
annulus, which effectively increases the velocity of a fixed air volume. If the required up-hole velocity is not achievable, add foam to help remove cuttings.

  Effectively removing cuttings as drilling progresses is critical. When the drill bit is extended in the
splines, to the open position, the maximum volume of air passes through the drill. Cuttings may not be
removed efficiently from the hole, resulting in an accumulation of cuttings around the drill. Accumulation
may increase when compressor capacity is insufficient to maintain maximum pressure while drilling. This condition may be signaled by the drill sticking, which retards downward movement and affects bit load and drilling energy. The sound of the drill indicates this problem. Apparent change in the air return,
cuttings returned from the annulus, and other indicators learned from experience also indicate an
accumulation problem.
  Detrimental effects of inefficient cuttings removal include reduced penetration rate, damage to the
formation by fracturing, induced instability in the hole wall, damage to or even loss of drilling equipment, and loss of the borehole. Accumulation may be caused by insufficient drilling air volume, a percussion
drill not suited for the hole, a sudden influx of groundwater, or too rapid a penetration rate (large load of
cuttings). The alert driller senses a problem before it seriously affects the operation. Keep the hole and blow out all cuttings before shutting off the air to add another rod. By raising the drill slightly, the bit is extended in the splines (open piston), the percussive action stops, drill bit penetration (production of
cuttings) stops, and maximum air passes through the drill to clear cuttings from the borehole. The alert and efficient operator uses this technique as conditions dictate.
  The down-hole percussion drill is designed to operate in extremely unfavorable conditions. The service
life is dependent on proper care. Lubricate the drill during operation. Use the manufacturer's recommended injection of a minimum of one quart of rock drill oil during each hour of drilling. During
drilling, the WDS is oiled with an in-line oiler plumbed into the drilling air line. Water injection into the air line is common and is not detrimental to the lubrication process. Drill rigs used for pneumatic drilling are equipped with a small, positive displacement pump (injection pump). Injecting water is helpful
because it reduces dust at the surface, improves cuttings removal, and stabilizes the borehole wall. A
water injection of 2 to 5 gpm is satisfactory. Adjust injection rates to the specific material drilled. Water injection improves lubrication of the drill string, provides some cooling of the compressed air and drill system, and is beneficial for rock drilling.
  When the drill is removed from the borehole, break it down, inspect it, clean it, and repair it, as necessary.
Oil all machined surfaces and lubricate threads with tool-joint compound before returning the drill to the borehole or to storage. Often a drill is left idle in the hole for an extended period. If this occurs, lubricate the drill. Lift the drill off the bottom, close the water injection valve, blow air through the hammer, and add oil (1 to 2 quarts) to circulate and lubricate the surfaces. Reasonable service and care improve the life of the drill.

## 4.4 Drilling Information

1. *Driller's Log*. Prepare a driller's log for every well drilled. The log contains data, such as water-bearingstrata information, used to locate and drill a well. Figure 4-23 (DD Form 2678) and Figure 4-24 (DD Form 2679) provide examples of a well driller's log and piping and casing log respectively. These forms are in the back of this manual for reproduction and use. Items to record in the remarks section of the well driller's log could include the following:
a. Changes in circulation, color, and consistency of drilling fluid. b. Observations of the cuttings carried to the surface.
c. Depth to material contacts. d. Size and apparent classification of the cuttings.
e. Fluid loss or gain. f. Penetration rate. g. Soil description (fine or course, clay or sand).
2. *Soil Sampling*. Try to obtain good material samples and log the depth from which the samples came.
Cuttings continuously wash to the surface during drilling. These cuttings are useful, but are not the
samples mentioned above. To collect a specific cutting sample, stop drilling and continue fluid circulation
to wash most of the cuttings from the hole. When the hole is clean, advance the bit through the sampling interval and stop. Collect samples from the fluid of the drilled section and resume drilling after taking samples. Although redundant sampling impacts drilling progress, worthwhile information is obtained and must be done irrespective to schedule impact. Field modifications of well design are often required, especially when subsurface information is sparse. In most cases, the changes made during well drilling are minor. For example, placing a screen a few ft higher or lower to match the position of the most gravelly
part of an aquifer or adjusting a grout interval to match an impermeable layer above the aquifer.
INTENTIONALLY BLANK

## Chapter 5 Well-Installation Procedures 5.1 Setting Casing

In rotary-drilled water wells, the surface casing may be set in the borehole after drilling is finished. However, the casing must be set and grouted near the surface. This prevents the upper portion of the borehole from caving in.

For water wells drilled in rock aquifers, the casing may be placed through the unconsolidated strata and into the rock to get a tight seal. However, this method does not ensure a tight seal. Improvement to the seal is accomplished by using the following procedures:

- Step 1. Drill a borehole about 10 ft into the rock. - Step 2. Flush the hole with clean water. - Step 3. Fill the rock interval with grout, and immediately set the casing into the hole. Let the grout set
around the bottom of the casing.
- Step 4. Drill through the grout, plug in the lower casing, and progress into the aquifer. - Step 5. Complete an open-hole well or install a smaller casing and screen inside the outer casing.
Grout cannot be poured through drilling fluid to properly seal the casing.

## 5.2 Selecting Casing

Well casing is plastic, wrought iron, alloyed or unalloyed steel, or ingot iron. Well-completion kits have either plastic (see Figure 5-1) or steel casing. It is important to understand the properties of different material since availability factors into usage decisions. When selecting the casing, consider the stress factor during the installation process, the corrosive element of the water, and the subsurface formation. If casings other than those in the well-completion kits are used, the weight per ft of pipe must be specified. The tables in A100-66, American Water Works Association (AWWA), *Standard for Deep Wells,* present data on the steel and wrought-iron pipes used as permanent well casings. Joints for permanent casings should have threaded couplings or should be welded or cemented so they are watertight from the bottom of the casing to a point above ground. This precaution prevents contaminated surface water and groundwater from entering the system. Figure
5-2 lists hole diameters for various sizes and types of well casings.

When using polyvinyl chloride (PVC) casing do not store in direct sunlight.

## 5.3 Installing Casing

The list below describes various methods for installing casing:

1. *Open-Hole Method*. With this method, install casing using the following procedures:
- Step 1. Clean the borehole by allowing the fluid to circulate with the drill bit close to the bottom so
cuttings come to the surface. The borehole may be carried deeper than necessary so that if any material caves in, the material fills the extra space below the casing depth.
- Step 2. Attach a coupling to the top of the casing. Suspend the casing by either attaching a hoisting
plug to the coupling, using a sub (adapter) if necessary, or by placing a casing elevator or a pipe clamp
around the casing under the coupling.
- Step 3. Lower the first length of casing until the coupling, casing elevator, or pipe clamp rests either on
the rotary table or on another support placed around the casing. If lifting with a sub, unscrew the sub on the first length of casing and attach it to the second length of casing. If lifting by elevators or pipe
clamps, release the elevator bails from the casing in the hole, and attach it to another elevator casing or
pipe clamp on the second length of casing. Lift it into position, and screw it into the coupling of the
first casing length (lightly coat the threads of the casing and coupling with a thin oil). Screw the lengths tightly together to prevent leaking. Remove the elevator or other support from the casing in the hole and lower the string that is supported by the uppermost coupling.
- Step 4. Repeat the procedure for each casing length installed. If a cave-in occurs, attach a swivel to the
casing with a sub and circulate the drilling fluid through the casing to flush out the hole and wash the casing down. After the casing is set on the bottom of the hole, drill through the casing into the aquifer.
2. *Single-String Method*. With this method, install the casing and screen (that have been joined) in a single
assembly. Refer to Paragraph 5.6 for additional details on screen installation.
3. *Wash-In Method (Jetted Wells)*. With this method, the borehole is advanced for an expedient jetted-well
construction. The water source is attached to the casing and screening. A pointed bottom cap allows high
pressure water or air to be forced through it to move cuttings as casing string is inserted in hole (similar to
forcing a water hose into ground).  This method is ideal for soft, sandy material and shallow wells.
4. *Driven Method (Driven Wells)*. Install the casing as with the borehole, the cable-tool, or the driven-point
well method. This method is not a military standard and requires special attachments. The drill bit advances just ahead of the casing and both go into the ground at the same time.

| Inside    | Wall     | Outside    |
|-----------|----------|------------|
| Diameter  | Diameter | Thickness  |
| Water     | Schedule |            |
| Number    | in       | mm         |
| ft        | meters   |            |
| 40 (STD)  |          |            |
| 6.625     |          |            |
| 6.625     |          |            |
| 6.625     |          |            |
| 6.625     |          |            |
| 6.625     |          |            |
| 168.3     |          |            |
| 168.3     |          |            |
| 168.3     |          |            |
| 168.3     |          |            |
| 168.3     |          |            |
| 6.313     |          |            |
| 6.249     |          |            |
| 6.187     |          |            |
| 6.125     |          |            |
| 6.065     |          |            |
| 160.3     |          |            |
| 158.7     |          |            |
| 157.1     |          |            |
| 155.5     |          |            |
| 154.1     |          |            |
| 0.156     |          |            |
| 0.188     |          |            |
| 0.219     |          |            |
| 0.250     |          |            |
| 0.280     |          |            |
| 20        |          |            |
| 30        |          |            |
| 40 (STD)  |          |            |
| 8.625     |          |            |
| 8.625     |          |            |
| 8.625     |          |            |
| 8.625     |          |            |
| 8.625     |          |            |
| 219.1     |          |            |
| 219.1     |          |            |
| 219.1     |          |            |
| 219.1     |          |            |
| 219.1     |          |            |
| 8.250     |          |            |
| 8.187     |          |            |
| 8.125     |          |            |
| 8.071     |          |            |
| 7.981     |          |            |
| 209.5     |          |            |
| 207.9     |          |            |
| 206.3     |          |            |
| 205.1     |          |            |
| 202.7     |          |            |
| 0.188     |          |            |
| 0.219     |          |            |
| 0.250     |          |            |
| 0.277     |          |            |
| 0.322     |          |            |
| 20        |          |            |
| 30        |          |            |
| 40 (STD)  |          |            |
| 10.75     |          |            |
| 10.75     |          |            |
| 10.75     |          |            |
| 10.75     |          |            |
| 273.1     |          |            |
| 273.1     |          |            |
| 273.1     |          |            |
| 273.1     |          |            |
| 10.374    |          |            |
| 10.250    |          |            |
| 10.136    |          |            |
| 10.020    |          |            |
| 263.5     |          |            |
| 260.3     |          |            |
| 257.5     |          |            |
| 254.5     |          |            |
| 0.188     |          |            |
| 0.250     |          |            |
| 0.307     |          |            |
| 0.365     |          |            |
| 20        |          |            |
| 30        |          |            |
|           | (STD)    |            |
| 12.75     |          |            |
| 12.75     |          |            |
| 12.75     |          |            |
| 12.75     |          |            |
| 12.75     |          |            |
| 323.9     |          |            |
| 323.9     |          |            |
| 323.9     |          |            |
| 323.9     |          |            |
| 323.9     |          |            |
| 12.374    |          |            |
| 12.250    |          |            |
| 12.126    |          |            |
| 12.090    |          |            |
| 12.000    |          |            |
| 314.3     |          |            |
| 311.1     |          |            |
| 308.1     |          |            |
| 307.1     |          |            |
| 304.9     |          |            |
| 0.188     |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.330     |          |            |
| 0.375     |          |            |
| 0.188     |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 346.0     |          |            |
| 342.8     |          |            |
| 339.8     |          |            |
| 336.6     |          |            |
| 13.624    |          |            |
| 13.500    |          |            |
| 13.376    |          |            |
| 13.250    |          |            |
| 355.6     |          |            |
| 355.6     |          |            |
| 355.6     |          |            |
| 355.6     |          |            |
| 14.0      |          |            |
| 14.0      |          |            |
| 14.0      |          |            |
| 14.0      |          |            |
| 10        |          |            |
| 20        |          |            |
| 30 (STD)  |          |            |
| 0.219     |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| 395.2     |          |            |
| 393.6     |          |            |
| 390.6     |          |            |
| 387.4     |          |            |
| 381.0     |          |            |
| 15.562    |          |            |
| 15.500    |          |            |
| 15.376    |          |            |
| 15.250    |          |            |
| 15.000    |          |            |
| 406.4     |          |            |
| 406.4     |          |            |
| 406.4     |          |            |
| 406.4     |          |            |
| 406.4     |          |            |
| 16.0      |          |            |
| 16.0      |          |            |
| 16.0      |          |            |
| 16.0      |          |            |
| 16.0      |          |            |
| 10        |          |            |
| 20        |          |            |
| 30 (STD)  |          |            |
| 40 (XS)   |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| 444.4     |          |            |
| 441.4     |          |            |
| 438.2     |          |            |
| 431.8     |          |            |
| 17.500    |          |            |
| 17.376    |          |            |
| 17.250    |          |            |
| 17.000    |          |            |
| 457.2     |          |            |
| 457.2     |          |            |
| 457.2     |          |            |
| 457.2     |          |            |
| 18.0      |          |            |
| 18.0      |          |            |
| 18.0      |          |            |
| 18.0      |          |            |
| 10        |          |            |
| 20        |          |            |
|           | (STD)    |            |
|           | (XS)     |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| 495.2     |          |            |
| 492.2     |          |            |
| 489.0     |          |            |
| 482.6     |          |            |
| 19.500    |          |            |
| 19.376    |          |            |
| 19.250    |          |            |
| 19.000    |          |            |
| 508.0     |          |            |
| 508.0     |          |            |
| 508.0     |          |            |
| 508.0     |          |            |
| 20.0      |          |            |
| 20.0      |          |            |
| 20.0      |          |            |
| 20.0      |          |            |
| 10        |          |            |
|           |          |            |
| 20 (STD)  |          |            |
| 30 (XS)   |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| 546.0     |          |            |
| 543.0     |          |            |
| 539.8     |          |            |
| 533.4     |          |            |
| 22.0      |          |            |
| 22.0      |          |            |
| 22.0      |          |            |
| 22.0      |          |            |
| 558.8     |          |            |
| 558.8     |          |            |
| 558.8     |          |            |
| 558.8     |          |            |
| 21.500    |          |            |
| 21.376    |          |            |
| 21.250    |          |            |
| 21.000    |          |            |
| 10        |          |            |
|           |          |            |
| 20 (STD)  |          |            |
| 30 (XS)   |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| 609.6     |          |            |
| 609.6     |          |            |
| 609.6     |          |            |
| 609.6     |          |            |
| 23.500    |          |            |
| 23.376    |          |            |
| 23.250    |          |            |
| 23.000    |          |            |
| 596.8     |          |            |
| 593.8     |          |            |
| 590.6     |          |            |
| 584.2     |          |            |
| 10        |          |            |
|           |          |            |
| 20 (STD)  |          |            |
|           | (XS)     |            |
| 24.0      |          |            |
| 24.0      |          |            |
| 24.0      |          |            |
| 24.0      |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| 10        |          |            |
|           | (STD)    |            |
| 20 (XS)   |          |            |
| 26.0      |          |            |
| 26.0      |          |            |
| 26.0      |          |            |
| 26.0      |          |            |
| 660.4     |          |            |
| 660.4     |          |            |
| 660.4     |          |            |
| 660.4     |          |            |
| 25.500    |          |            |
| 25.376    |          |            |
| 25.250    |          |            |
| 25.000    |          |            |
| 647.6     |          |            |
| 644.6     |          |            |
| 641.4     |          |            |
| 635.0     |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| 10        |          |            |
|           | (STD)    |            |
| 20 (XS)   |          |            |
| 28.0      |          |            |
| 28.0      |          |            |
| 28.0      |          |            |
| 28.0      |          |            |
| 711.2     |          |            |
| 711.2     |          |            |
| 711.2     |          |            |
| 711.2     |          |            |
| 27.500    |          |            |
| 27.376    |          |            |
| 27.250    |          |            |
| 27.000    |          |            |
| 698.4     |          |            |
| 695.4     |          |            |
| 692.2     |          |            |
| 685.8     |          |            |
| 10        |          |            |
|           | (STD)    |            |
| 20 (XS)   |          |            |
| 30.0      |          |            |
| 30.0      |          |            |
| 30.0      |          |            |
| 30.0      |          |            |
| 762.0     |          |            |
| 762.0     |          |            |
| 762.0     |          |            |
| 762.0     |          |            |
| 29.500    |          |            |
| 29.376    |          |            |
| 29.250    |          |            |
| 29.000    |          |            |
| 749.2     |          |            |
| 746.2     |          |            |
| 743.0     |          |            |
| 736.6     |          |            |
| 0.250     |          |            |
| 0.312     |          |            |
| 0.375     |          |            |
| 0.500     |          |            |
| Weight    |
|-----------|
| 4.0       |
| 4.8       |
| 5.6       |
| 6.4       |
| 7.1       |
| 10.78     |
| 12.92     |
| 14.98     |
| 17.02     |
| 18.97     |
| 16.04     |
| 19.22     |
| 22.29     |
| 25.33     |
| 28.23     |
| 600       |
| 1,030     |
| 1,521     |
| 1,953     |
| 2,286     |
| 4,137     |
| 7,102     |
| 10,48     |
| 13,466    |
| 15,76     |
| 1,386     |
| 2,379     |
| 3,511     |
| 4,510     |
| 5,279     |
| 423       |
| 725       |
| 1,070     |
| 1,375     |
| 1,609     |
| 4.8       |
| 5.6       |
| 6.4       |
| 7.0       |
| 8.2       |
| 16.94     |
| 19.66     |
| 22.36     |
| 24.70     |
| 28.55     |
| 25.21     |
| 29.25     |
| 33.27     |
| 36.75     |
| 42.48     |
| 477       |
| 750       |
| 1,092     |
| 1,422     |
| 1,920     |
| 3,289     |
| 5,171     |
| 7,529     |
| 9,805     |
| 13,23     |
| 1,101     |
| 1,731     |
| 2,522     |
| 3,284     |
| 4,433     |
| 336       |
| 528       |
| 769       |
| 1,001     |
| 1,352     |
| 4.8       |
| 6.4       |
| 7.8       |
| 9.3       |
| 21.21     |
| 28.04     |
| 34.24     |
| 40.48     |
| 31.56     |
| 41.72     |
| 50.95     |
| 60.23     |
| 246       |
| 579       |
| 1,048     |
| 1,611     |
| 1,696     |
| 3,992     |
| 7,226     |
| 11,10     |
| 568       |
| 1,336     |
| 2,421     |
| 3,721     |
| 173       |
| 407       |
| 738       |
| 1,134     |
| 4.8       |
| 6.4       |
| 7.9       |
| 8.4       |
| 9.5       |
| 25.22     |
| 33.38     |
| 41.45     |
| 43.77     |
| 49.56     |
| 37.53     |
| 49.67     |
| 61.68     |
| 65.13     |
| 73.75     |
| 147       |
| 347       |
| 673       |
| 793       |
| 1,136     |
| 1,014     |
| 2,393     |
| 4,640     |
| 5,468     |
| 7,833     |
| 339       |
| 801       |
| 1,553     |
| 1,830     |
| 2,624     |
| 103       |
| 244       |
| 473       |
| 558       |
| 800       |
| 78        |
| 184       |
| 359       |
| 616       |
| 255       |
| 604       |
| 1,177     |
| 2,021     |
| 765       |
| 1,806     |
| 3,516     |
| 6,033     |
| 111       |
| 262       |
| 510       |
| 875       |
| 41.26     |
| 54.62     |
| 67.87     |
| 81.20     |
| 27.73     |
| 36.71     |
| 45.61     |
| 54.57     |
| 4.8       |
| 6.4       |
| 7.9       |
| 9.5       |
| 82        |
| 123       |
| 240       |
| 417       |
| 937       |
| 270       |
| 404       |
| 788       |
| 1,367     |
| 3,072     |
| 807       |
| 1,207     |
| 2,351     |
| 4,082     |
| 9,177     |
| 117       |
| 175       |
| 341       |
| 592       |
| 1,331     |
| 54.92     |
| 62.57     |
| 77.78     |
| 93.12     |
| 123.2     |
| 36.91     |
| 42.05     |
| 52.27     |
| 62.58     |
| 82.77     |
| 5.6       |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 86        |
| 168       |
| 293       |
| 683       |
| 283       |
| 552       |
| 962       |
| 2,241     |
| 841       |
| 1,648     |
| 2,875     |
| 6,688     |
| 122       |
| 239       |
| 417       |
| 970       |
| 70.52     |
| 87.70     |
| 105.0     |
| 139.1     |
| 47.39     |
| 58.94     |
| 70.59     |
| 93.45     |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 63        |
| 123       |
| 213       |
| 504       |
| 205       |
| 402       |
| 700       |
| 1,654     |
| 614       |
| 1,200     |
| 2,089     |
| 4,937     |
| 89        |
| 174       |
| 303       |
| 716       |
| 78.46     |
| 97.61     |
| 117.0     |
| 154.9     |
| 52.73     |
| 65.60     |
| 78.60     |
| 104.1     |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 47        |
| 92        |
| 160       |
| 380       |
| 66        |
| 130       |
| 227       |
| 540       |
| 455       |
| 896       |
| 1,565     |
| 3,723     |
| 154       |
| 301       |
| 525       |
| 1,248     |
| 86.41     |
| 107.5     |
| 128.9     |
| 170.8     |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 58.07     |
| 72.27     |
| 86.61     |
| 114.8     |
| 352       |
| 690       |
| 1,207     |
| 2,875     |
| 118       |
| 231       |
| 404       |
| 962       |
| 36        |
| 70        |
| 123       |
| 293       |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 63.41     |
| 78.93     |
| 94.62     |
| 125.5     |
| 94.35     |
| 117.4     |
| 140.8     |
| 186.7     |
| 51        |
| 100       |
| 175       |
| 417       |
| 102.3     |
| 127.4     |
| 152.7     |
| 202.7     |
| 40        |
| 79        |
| 137       |
| 327       |
| 276       |
| 545       |
| 945       |
| 2,255     |
| 93        |
| 181       |
| 317       |
| 756       |
| 28        |
| 55        |
| 97        |
| 230       |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 68.75     |
| 85.60     |
| 102.6     |
| 136.2     |
| 110.2     |
| 137.3     |
| 164.6     |
| 218.6     |
| 32        |
| 63        |
| 110       |
| 262       |
| 221       |
| 434       |
| 758       |
| 1,806     |
| 74        |
| 145       |
| 253       |
| 604       |
| 23        |
| 44        |
| 77        |
| 184       |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 74.09     |
| 92.26     |
| 110.6     |
| 146.9     |
| 6.4       |
| 7.9       |
| 9.5       |
| 12.7      |
| 79.43     |
| 98.93     |
| 118.7     |
| 157.5     |
| 118.2     |
| 147.2     |
| 176.6     |
| 234.4     |
| 26        |
| 51        |
| 89        |
| 213       |
| 179       |
| 352       |
| 614       |
| 1,469     |
| 60        |
| 118       |
| 205       |
| 491       |
| 18        |
| 36        |
| 63        |
| 150       |

5. *Uncased-Interval Method*. In rock, the lower portion of the borehole is normally left uncased because
water emerges from irregular functions in the borehole wall. Therefore, for the well to function properly,
care is necessary when locating the bottom of the cased portion in relation to any impermeable zone. Once the depth is established, drill down and set the casing and then drill a smaller hole to full depth and proceed with development.

## 5.4 Grouting And Sealing Casing

Once grout is mixed, it starts to set. Therefore, place the mixture immediately after mixing it. The grout must be freshly mixed continuously to meet requirements. Portland cement meets most grouting requirements (a quickhardening cement may be used to save time). For proper consistency, use no more than 6 gallons of water per 94- pound sack of cement. If a large amount of grout is necessary, add 1 cubic ft of fine or medium sand for each sack of cement. Add a few lbs of bentonite or hydrated lime per sack of cement for a better flow. For small jobs, and if no equipment is available, use a 55-gallon steel drum as a mixing tank. Put 20 to 24 gallons of water in the barrel and slowly add 4 bags of cement while stirring or jetting the water. Use as many mixing barrels as the job requires. If a concrete mixer is available, mix batches and dump them into a storage vat for future use.

Grout may be forced into place using pumps or air or water pressure. In some cases, use of a dump bailer is possible. If the tremie method is used, one or more strings of pipe with small diameters is necessary. Other equipment necessary are a mixing tank, hoses, and a feed hopper. The list below describes various methods for placing grout:

1. *Dump-Bailer Method*. With this method, grout is simply placed and with a minimum amount of
equipment. On the dump-bailer, the bottom valve opens and the operator unloads grout at a specified location. This method works best for grouting only the lower portion of the casing. Use the following procedures to place grout:
- Step 1. Run the casing in the hole and mix enough grout to fill the lower 20 to 40 ft of the hole (a quick
method of mixing the grout is to put the required amount of water in a barrel and circulate the water, using a high-pressure jet while adding cement).
- Step 2. Place the grout inside the casing with a dump-bailer. - Step 3. Lift the string of casing 20 to 40 ft off the bottom, depending on the amount of grout placed. The
lower end of the casing should be below the top of the grout. Fill the casing with water and cap the top.
- Step 4. Lower the casing to the bottom of the hole to force most of the grout up the annular space
outside of the casing. Do not uncap the top of the casing until the grout is set.
- Step 5. Drill through the cement that has hardened in the lower end of the casing and continue drilling
to the required depth (green cement increases the viscosity of the drilling mud).
  If difficulty is anticipated in filling the casing with water when it is lifted in the borehole, add water on top
of the grout without lifting the casing. Calculate the volume of grout in the casing. Fill the casing to the
top with water. Connect a pump to force in additional water. Pump water into the casing, measuring the volume pumped, until a quantity equal to the volume of grout is put in. This forces all or most of the grout out of the lower end of the casing. Place a wad of burlap on top of the grout before filling the casing with
water to keep the fluids separated.
2. *Inside-Tremie Method*. With this method, place the grout in the bottom of the hole through a tremie pipe
that is set inside the casing (see Figure 5-3). The grout either descends naturally or a pump is necessary to force it through the pipe. Make sure that the tremie pipe is at least 1-inch in diameter. With this method and any other method where grout is placed inside the casing, make sure that water or drilling fluid circulates up and around the casing before starting to grout. To check this, cap the casing and pump in water. If the water comes to the surface outside the casing, start grouting. Use the following procedures to
complete the tremie method:
- Step 1. Continue pouring grout until it appears at the surface around the casing. Once the grout reaches
the desired depth, it fills the space around the outside of the casing.
- Step 2. Suspend the casing about 2-ft above the bottom of the borehole during the operation. Once the
grout is in place, lower and seat the casing in a permanent position.  Remove and clean the tremie pipe. The check valve prevents the grout from moving back into the casing.
- Step 3. The grout should set and harden in about 24 to 72 hours, depending on the cement used. Drill
out the packer and continue drilling the well below the grouted casing.
3. *Outside-Tremie Method.* With this method, use a tremie pipe to deliver grouting outside the casing. This
method is not recommended for depths greater than 100 ft. Only use this method if the space between the
casing and the borehole wall is large enough to contain a 1-inch tremie pipe. Use the following procedures to complete grouting using this method:
- Step 1. Lower the pipe to the bottom. Make sure that the lower end of the casing is tightly seated at the
bottom of the borehole.
- Step 2. Mix a sufficient quantity of grout and pump it through the tremie pipe or let it descend naturally
(see Figure 5-4). As the grout is placed, lift the tremie pipe slowly, but keep the lower end submerged in the grout.
- Step 3. Fill the casing with water as the grout is placed to balance the fluid pressure inside and outside
the casing. Doing so prevents grout from leaking under the bottom of the casing.
Grouting near the surface is accomplished quickly using a tremie or by dumping the grout in the hole around the casing and puddling it with pipe lengths. However, this procedure only provides a surface seal around the casing and cannot be used as a normal grouting method.

## Grouting Around Pvc Pipe May Cause Excess Pressure That May Collapse The Piping. 5.5 Selecting Screens

The military uses continuous-slot screens (see Figure 5-5) when drilling wells using the rotary method. Screens are fabricated by winding triangular sections around a skeleton of longitudinal rods. Join the triangular sections and rods securely wherever they cress. The screens are constructed of either PVC or stainless steel and are packed in the well-completion kits. Some important factors to remember when selecting screens are that they:

1. Must produce a sand-free well of less than 2 ppm. 2. Should prevent minimum head loss. 3. Should be of a commercial grade (screen sizes are in increments of 0.005 inch). 4. Should lend themselves well to development (allow for a two-way flow).
The list below describes selection and sizing of screens:

1. *Types.*
a. *PVC Screens*. These screens must be at least 8-inches in diameter. Continuous-slot PVC screens are in
the 600-ft well-completion kits packed in boxes containing four 20-inch-long sections that are joinable (see Figure 5-6). The kits contain enough sections to assemble up to 50 ft of continuous-slot, 8-inch well screen.
  The PVC casings may be used to construct an alternative screen in the field by sawing or milling
horizontal slots in sections of the 20-ft-long casing (cut six rows of slots down the casing). The slots are a 12-inch apart at a width of 0.025-inches. The following lists saws and approximate slot sizes:
(1) Hacksaw, about 0.035 inches.
(2) Handsaw, 0.050 to 0.080 inches. (3) Circular saw, 0.100 to 0.125 inches.
  These makeshift screens are not as efficient as the continuous-slot screens because of the relatively low
open area per ft of screen. However, these screens may be necessary if the kit contains an insufficient
number of continuous-slot screens. The alternative screens are the same as the casing sections. Place
the screens intermittently up the well if more than one aquifer or water-bearing strata is screened. If multiple intervals are screened, place gravel packs around the screens and backfill between the screens. If sufficient gravel-pack material is available, use it continuously above the top of the screen.
b. *Stainless-Steel Screens*. These screens are usually 6 inches in diameter and come in 9- and 20-ft
sections. The sections are joinable to make longer pieces. Most stocked screens have 0.025-inch
openings that are suitable for medium-sand formations. Screens with other slot openings are available and may be needed for special installations. Various end fittings are available to accommodate different installation methods. See Paragraph 5.6 for uses of these end fittings.
c. *Pipe-Base screen*. This screen is made by wrapping a trapezoidal-shaped wire around a pipe base that
has drilling holes evenly spaced. A pipe-base screen is strong and suitable for deep wells. The screen
has two sets of openings; outer openings are between adjacent turns of the wrapping wire and inner openings are the holes drilled in the pipe base. The percentage of open area per ft of screen (usually low) governs the efficiency of the screen. These screens come in 3- and 4-inch pipe bases for field
OPS.
2. *Lengths*. Screen length should not exceed the thickness of thin aquifers. Screen the bottom third of
unconfined aquifers and 75 to 80 percent of confined aquifers. However, for interlayered fine and coarse
beds, consider the thickness of the coarse strata when determining screen length. Set the screen in the coarse strata. When choosing slot sizes, consider the percentage of the open area or intake area of the well
screen to determine length. Use the following calculations to determine the amount of screen to use during drilling OPS:
a. Surface Area.
SA = (OD) (12)
where:
SA   = surface area, in inches per ft.

OD = outside diameter of the screen, in inches.

b. Open Area.
WD100 SO SO OA + =
where:
OA  = open area as a percentage. SO   = slot opening, in inches.

WD = wire diameter, in inches.

c. Total Area.
TA = (SA)(OA) where: TA  = total area, in square inches. SA  = surface area, in inches per ft. OA = open area, as a percentage.

d. Transmitting Capacity.
TC = (TA)0.31 where: TC = transmitting capacity, in gpm per ft of screen (based on one-tenth ft per minute of velocity).

TA = total area, in square inches.

e. Screen Length.
TC
SL = PR

where: SL = screen length required, in linear ft. PR = pumping requirement, in gpm. TC = transmitting capacity, in gpm.

  The following example uses the above equations to determine the amount of 12-inch screen required at
one-tenth ft per minute of velocity with a slot opening of 0.040-inches, a wire size of 0.092 inch, and a
pumping requirement of 800 gpm:
$\text{SA}=\pi\text{(OD)}(12)=(3.14)(12)(12)=452.16$ square inches.

$\text{OA}=\dfrac{\text{SO}}{\text{SO}+\text{WD}}100=\dfrac{0.040}{0.040+0.092}100=30.30$ percent.

$\text{TA}=\text{(SA)(OA)}=(452.16)(.3030)=137$ square inches.

$\text{TC}=\text{(TA)}0.31=(137)(0.31)=42.47$ gpm.

$\text{SL}=\dfrac{\text{PR}}{\text{TC}}=\dfrac{800}{42.47}=18.83$ linear feet.

3. *Diameters*. The diameter of the well screen usually corresponds to the diameter of the well casing. The
following considerations are also germane:
a. Increasing the screen diameter increases the yield or capacity of a well. The increase is not
proportional.
b. Doubling the diameter of a well screen increases the capacity of the well by about 10 percent.
c. Using a larger diameter screen if the aquifer is thin or the pump is large facilitates better performance.
d. Using a long screen with a smaller diameter in a thick aquifer facilitates better performance.
e. Increasing the length, not the diameter, of the screen increases the yield of a well in a thick aquifer.
4. *Slot Sizes*. The function of slot size in well construction is important. When possible, choose the screen
slot size to fit the gradation or grain sizes of the aquifer. Sand and gravel interaction greatly affects the
development of the formation around the screen. Small openings limit well yield. Also, small slot sizes produce high velocity in the water passing through the screen. In time, scale or incrustation tends to form on the screen. If the openings are too large, the well may require more development than usual or it may not be able to clear the well of sand.
  Screen slots that are sized to retain the coarsest one-third to one-half of sand or gravel of the aquifer work
best in a naturally developed well. About two-thirds of the sand in the layer behind the screen should pass through the slots. A screen set across both coarse and fine strata may need sections with different slot sizes. If the screen requires artificial gravel packing, make sure the slot openings correspond to the size of the gravel selected. Screen openings that retain about nine tenths of the gravel works best.

## 5.6 Installing Screen

Several methods are possible to install screens in rotary-drilled wells. To set well screens, use the screen hook and casing elevators. The hook engages a bail in the bottom of the screen to suspend the screen on either the sand line or hoist line while lowering the screen into the well (see Figure 5-7). Do not pull the screen with the hook after the formation has closed in around the screen. If installing a screen, use the telescoping method and seal the casing (rubber or neoprene packers are necessary). All screen-setting methods require accurate and complete measurements of pipe, screen, cable length, and hole depth. The list below describes screen installation methods:

1. *Single-String Method*. With this method, install the casing and screen as one assembly. Figure 5-8 shows a
single-string assembly equipped with fittings for the washdown method. The washdown fittings may be omitted if the hole stays open at the bottom. Use the following procedures to install the assembly:
- Step 1. Attach couplings to the top of the casing and screen section. Install a sand trap to the bottom of
the string.
- Step 2. After running the entire string into the borehole, use casing elevators to carry most of the
weight of the string until the formation collapses in around the screen.
- Step 3. Run the drill pipe inside the casing to the bottom of the screen, and pump water into the well to
displace the drilling fluid.
- Step 4. Raise and lower the drill pipe to wash the full length of the screen.
- Step 5. Wait for the formation to settle around the screen. Proceed with well completion and
development.
For deep wells and wells requiring surface casing, use the following modified telescoping procedure:

- Step 1. Grout the surface casing in the borehole before drilling the well to the final depth.
- Step 2. Use the single-string method inside the surface casing, while bringing the inner casing to the surface.
- Step 3. After placing the gravel pack around the screen and impervious backfill on top of the gravel,
grout the entire annulus between the inner and outer casing to the surface.
  A disadvantage of the single-string method is the weight of a long string of casing on top of the screen.
When the screen touches bottom, it becomes a loaded column that easily buckles because of its
slenderness. When the screen reaches the correct depth, buckling is preventable by supporting the screen
on casing elevators until the formation material collapses around the screen and supports it laterally.
2. *Pull-Back Method*. This is another method of installing a telescoping screen. It is used when the drilled
material is so loose, surface casing is needed to finish bottom hole depth. Use the following procedures
for this method:
- Step 1. Sink the well casing to the full depth of the well and clean out the hole to the bottom of the pipe
with the bailer.
- Step 2. Assemble the closed bail plug in the bottom of the screen and screw one or more packers to the
top of the bail plug.
- Step 3. Lower the screen inside the well casing using the sand line. After setting the screen on the
bottom, pull the casing back far enough to expose the screen in the aquifer and to a position where the
packer is still inside the casing.
- Step 4. Use a casing ring and slip with two hydraulic jacks to pull the pipe. If the screen moves upward
as the pipe is pulled, lower the drill bit or another tool inside the screen to hold the screen down.
- Step 5. Hold the casing with pipe clamps until either the hole caves around the casing and grips the pipe
or until grout is placed and sets around the casing, after pulling the casing to its permanent position.
- Step 6. Bail out the drilling mud so that the sand and gravel of the formation closes in around the screen.
3. *Open-Hole Method*. Use this method to install a telescoping screen when the depth and thickness of the
aquifer have been predetermined. Use the following procedures for this method:
- Step 1. Sink the well casing into the aquifer to a depth slightly below the desired position from the top
of the well screen. Fix the casing in place by grouting or other means.
- Step 2. Mix drilling mud and fill the casing. Using a bit that passes through the casing, drilling into the
aquifer below the casing to make room for the length of well screen to be exposed.
- Step 3. Lower the screen into position, ensuring that the rubber or neoprene packer remains inside the
casing near its lower end when the screen is on the bottom. If the hole is too deep, drop gravel into the
hole to the correct height.
  Use the closed bail plug and the packer top-end fittings to support the screen and sand trap (see Figure
5-9). With this method, the diameter of the screen must be smaller than the casing, since the hole drilled
for the screen is no larger than the ID of the casing. Also, make sure that the packer fitting at the top of the screen is the proper size to seal inside the casing. The drilling mud must be heavy and thick to prevent the open borehole from caving in and the mud must be completely removed from the aquifer during development.
4. *Washdown Method*. This method works best if the aquifer is composed of fine to coarse sand with little or
no gravel. The screen fittings necessary for this method are a washdown or self-closing bottom. Figure 5-10 shows a fitting when using a telescoping method to set the screen through the casing. Set the casing
from the surface to slightly below the depth where the top of the screen is installed. Screw a section of wash pipe into the left-hand female thread of the self-closing bottom and attach the bottom to the screen or sand trap with the wash pipe projecting through the screen. Lift the entire assembly by the wash pipe and lower the screen inside the casing. Add sections of wash pipe until the bottom of the screen is near the lower end of the casing.Use the following procedures for the washdown method:

- Step 1. Connect the top of the wash pipe to the kelly and start the mud pump. Circulate water (not
drilling mud) down the wash pipe.
- Step 2. Let the screen move down as circulation continues and material washes. Take measurements
and stop the descent of the screen when the packer is near the lower end of the casing. If drilling mud is still washing out of the well, continue pumping water until most of the mud is displaced.
- Step 3. Stop the pump and let the aquifer close in around the screen. When the formation develops
friction on the outer surface of the screen, turn the entire string of wash pipe to the right to unscrew the
left-hand joint at the bottom.
- Step 4. When the wash pipe is free, pump in more water. Raise and lower the string several times so
that the lower end travels the full length of the screen. This action washes out more drilling mud and some fine sand from the formation.
- Step 5. Start development work, remove the wash pipe, and continue the development work.
5. *Bail-Down Method*. With this method, special end fittings are necessary for the screen. Figure 5-11 shows
an assembled bail-down shoe in the bottom of the screen. The bail-down shoe has a special nipple that has
right- and left-hand threads and a coupling with right- and left-hand threads. Figure 5-12 shows a shoe
with a guide pipe that extends below the screen. Use the following procedures for the bail-down operation:
- Step 1. Start the operation after the well casing is sunk to its permanent position. The casing's lower
end should be slightly below where the top of the screen is installed.
- Step 2. Assemble the bail-down shoe, special nipple, and special coupling in the bottom of the screen. - Step 3. Screw a length of premeasured pipe into the right-hand half of the special coupling. This pipe,
that extends up through the screen is called the bailing pipe or conductor pipe.
- Step 4. Screw one or more packers to the top of the screen. - Step 5. Lift the whole assembly by the bailing pipe and lower the screen inside the well casing. Add
lengths of bailing pipe as the screen descends until it reaches the bottom of the borehole.
- Step 6. Mark off the length of the screen on the bailing pipe that projects above the casing, using the
top of the casing as the reference measuring point. Run a bailer or sand pump inside the bailing pipe
and start bailing sand from below the shoe.
- Step 7. As sand is removed from below the shoe by the bailer, the combined weight of the screen and
the string of bailing pipe cause the screen to move downward. Attach additional weights to the bailing
pipe, if necessary.
- Step 8. Monitor the progress of the work carefully and stop the operation when the screen reaches the
desired depth. The packer should be near the lower end of the casing, but still inside the casing. Accurate measurements avoids sinking the screen too far.
- Step 9. Drop a weighted and tapered wooden plug (see Figure 5-12) through the bailing pipe to plug the
special nipple on the bail-down shoe. When the plug is in place, unscrew the left-hand threaded joint at
the upper end of the nipple by turning the entire string of bailing pipe to the right. Remove the bailing pipe and proceed with well development.
  If a different type of bail-down shoe is used, the left-hand threaded connection for the bailing pipe may be
in the shoe opening or the packer fitting at the top of the screen. In either case, use the same procedures as above to bail-down, plug the bottom, and remove the bailing pipe.
  Under certain conditions, bail-down of a well screen is accomplished without using a bail-down shoe. The
bailing pipe is not connected to the screen. The pipe's lower end is fit with a flange or coupling large enough to press on the packer at the top of the screen. The weight of the bailing pipe rests on the screen. Fit the lower end of the screen with an open ring or a short piece of pipe. Be very careful when using this
method because the screen is not connected to the bailing pipe and the screen's movement is
uncontrollable from the surface. Careful measurements prevent sinking the screen too far. This method
should be limited to fairly short screens. Plug the bottom of the screen by putting a small bag of dry
concrete mix in the bottom and tapping the concrete lightly with the drill bit or another tool.

## 5.7 Placing Gravel

The most important criteria for gravel pack (artificial sand filters) are compatible grain sizes and screen slot openings. Grading should be in proper relation to the grading of the sand in the aquifer. Trouble may arise if the gravel is too coarse. Coarse, uniformly graded filter sand (about 1/8-inch) makes the best gravel pack for most fine-sand aquifers. Use fine gravel (1/4-inch maximum size) to pack aquifers consisting of medium or coarse sand. Use a screen with openings that cover about 90 percent of the gravel pack. The following is a field method for producing a filter material or gravel pack from a sand and gravel deposit for a medium sand aquifer:

- Step 1. Make two sieves with lumber. Cover one sieve with a 1/4- to 3/8-inch hardware cloth. Cover the other
sieve with window screen.
A layer of hardware cloth under the screen provides extra strength to the sieve.

- Step 2. Discard all material that does not go through the hardware cloth but that goes through the window
screen. Save the materials that the screen retains for analysis and logging purposes.
The list below describes gravel placement methods:

1. Open-Hole Placement. Where drilling mud keeps the borehole open, install a gravel pack using the
positive-placement method. This method is the most common and best suited to military field OPS. Use the following procedures for this placement method:
- Step 1. Drill a large diameter borehole the full depth of the well.
- Step 2. Set a smaller diameter screen and casing centered in the large diameter borehole.
Basket-type centering guides work best.

- Step 3. Fill the annular space around the screen with properly graded gravel.
- Step 4. Fill the borehole with gravel well above the top of the screen. Gravel works downward as sand
and silt are removed from the formation around the gravel pack by subsequent development.
  Development work must be thorough when drilling the borehole using the rotary method because the mud
cake on the borehole wall is sandwiched between the gravel pack and the face of the formation. Break up the mud cake and bring it up through the gravel into the well. Any mud cake not removed reduces the efficiency and yield of the completed well. To ensure that all of the mud cake is removed, limit the
thickness of the gravel envelope around the screen to a few inches. A common mistake is to drill a very
large borehole and use a small screen, making the gravel too thick for satisfactory results.
  Another common mistake is to try and place gravel pack into a small annular space, such as 1-inch. The
gravel pack usually bridges at a coupling and does not get down around the well screen. A 2-inch annular space is the minimum, although 3- to 5-inch spaces are best. Remember, the annular space is the difference between the outside of the casing and the wall of the borehole with the casing centered in the
hole. In most cases, the OD of the couplings must also be considered.
2. *Tremie Placement.* A tremie pipe is appropriate when placing gravel-pack materials in shallow to
moderately deep wells. The fine and coarse particles should not separate, as in the open-hole placement,
when the aggregate settles through the drilling fluid in the well. Lower a string of 2-inch (or larger) pipe into the annular space between the inner and outer casings. Feed the gravel into the hopper at the top of
the pipe. Feed water into the pipe with the gravel to avoid bridging the material in the pipe. The pipe rises as the gravel builds up around the well screen.
3. *Bail-Down Placement*. With this method, the gravel pack and screen are installed at the same time. Feed
the gravel around the screen as it goes downward with the screen. The bail-down shoe used is somewhat
larger than the screen so that gravel being added follows down and around as the screen sinks in the
formation. Figure 5-13 shows this operation. Development work is an essential part of this method. Screen openings must be larger than the grain size of the aquifer so enough aquifer sand passes through and the gravel pack replaces the sand around the screen.
4. *Double-Casing Placement*. With this method, gravel is used and placed as a temporary outer casing (see
Figure 5-14). It is used as another method when surface casing is required to complete final depth. The casing is pulled back as gravel is poured into the space. This method is somewhat similar to pull-back
screen installation.

## 5.8 Using Alternative Methods

The list below describes alternative methods:

1. *Formation Stabilizer*. When a gravel pack is not used, a formation-stabilizer material helps prevent
deterioration of the annular space outside the screen. Fine, loose strata may cave into that space, enter the
screened interval, and degrade the well. The decision to use this material usually occurs during the wellconstruction process. In unstable formations, consider stabilizing wherever the annular space is more than 2 inches thick.
  Grain size is important since the aquifer is developed naturally and as much as half of the stabilizing
material could flow through the screen. The grain size should average slightly coarser than that of the aquifer and should be well distributed. Use the following procedures when using formation stabilizer:
- Step 1. Center the screen at its final position in the open section of the borehole, using a centralizer if
needed.
- Step 2. Place the stabilizer material by dumping and tamping it down the hole or by using a tremie.
Raise the level of stabilizing material above the top of the screen and add additional material as development progresses.
- Step 3. As the well is developed, the level of the stabilizing material drops as the material is pulled into
the screen. This material must be replaced to maintain the level above the top of the screen.
2. *Unscreened Well*. In consolidated rock, the aquifer is usually tapped through numerous, irregularly spaced
fractures. Once cleared of mud and rock fragments, the fractures stay open and the intake interval functions efficiently for a longtime (a screen is usually not needed in such a rock well). If an unscreened well design is used, particular attention must be paid to the location of the top of the unscreened intake interval and its relation to the position and thickness of any impermeable layer.
INTENTIONALLY BLANK

## Chapter 6 Well-Completion Procedures Note

This chapter implements STANAG 2885 ENGR (Edition 4).

## 6.1 Well Development

Figure 6-1 describes different well development methods and some characteristics of each method. All methods are designed to produce a stable flow condition. The list below describes well development methods in more detail:

1. *Jetting Method*. This backwashing method is an effective way to remove caked drilling mud from the
borehole wall by lowering a jetting tool inside the screen. However, its primary disadvantage in military field OPS is that it requires a large supply of water. Use the following procedures for this method:
- Step 1. Attach the jetting tool (in the well-completion kit) to the bottom of the drill string (see Figure
6-2).
- Step 2. Use the string to lower this tool into the screen. - Step 3. Connect the upper end of the pipe to the kelly or the discharge side of the mud pump. - Step 4. Pump water into the screen and rotate the jetting tool slowly so that the horizontal jets of water
wash out through the screen openings.
- Step 5. Raise the string of pipe gradually and continue rotating to backwash the entire surface of the
screen. If possible, use a pump pressure of 100 psi.
  After covering the entire screen with the jetting tool, remove the tool. Remove the sand that has collected
in the sand trap with a bailer. Repeat this process until the well stops producing sand. If a significant
volume of material is removed during development, add more filter material around the screen to keep the
top of the gravel pack above the top of the screen.
2. *Pump-Surge Method*. This backwashing technique involves pumping water to the surface and letting the
water run back into the well through the pump-column pipe using an airlift or a deep-well turbine pump without a foot valve. See Chapter 7 for a discussion on pumps. Do not use the permanent well pump for development (pumping sand could damage the pump). Use the following procedure for this method:
- Step 1. Start the pump. As water comes to the surface, stop the pump to release the water. The power
unit and starting equipment determine the starting and stopping action of the pump. The effect is to lower and raise the water level in the well intermittently through the screen openings. Periodically, pump the well to remove the sand brought in by surging.
- Step 2. Remove the pump and bail out the material in the sand trap, after surging. - Step 3. Repeat the process until the well stops producing sand.

| Jetting                                                            | Effective on mud cake, needs abundant water          |
|--------------------------------------------------------------------|------------------------------------------------------|
| Pump-surge                                                         | Air-lift or deep-well pump needed                    |
| Gravity outflow                                                    | Simple and slow, bail or use small pump              |
| Pressure pumping                                                   | Mostly inefficient, potential leakage outside casing |
| Surge block                                                        | Simple, effective, and slow                          |
| Compressed air (open)                                              | Requires high submergence (head), needs a compressor |
| Compressed air (closed)                                            |                                                      |
| Potential leakage and disturbance outside casing, needs compressor |                                                      |
| and fittings                                                       |                                                      |

3. *Gravity-Outflow Method.* Backwashing by gravity outflow involves pouring water into the well rapidly to
produce outflow through the screen openings. Inflow through the screen is then produced by bailing water from the well rapidly. This is a slow surging technique requiring several minutes to complete a cycle. If the static water level is high enough to permit pumping by suction lift, use a small centrifugal pump
instead of the bailer to speed up the work. If there is room in the well casing, connect the discharge side of
the pump to a string of small diameter pipe that is lowered into the well. The water added is pumped down inside the screen, creating a turbulence that helps develop the formation.
4. *Pressure-Pumping Method*. Occasionally, wells are backwashed by capping the casing and pumping water
into the well under pressure.  Water is forced outward through screen openings similar to the closed-well method of using compressed air for development (see Paragraph 6.1, item 6): Pressure pumping is an inefficient method because the desirable surging effect is difficult to produce. The casing seal must be
tight in the borehole and prevent water from being forced up around the outside of the casing.
5. *Surge Block Method*. With this method, water is surged up and down in the casing with a surge block or
plunger. A surge block is a solid plunger, swab, or a plunger equipped with or without a valve opening (see
Figure 6-3). The valve-type plunger gives a lighter surging action than the solid type. Light surging is advantageous in developing tight formations. Therefore, start the surging process slowly and increase the force as the development proceeds. Be careful when working with wells using PVC pipe. The casing or well screen could collapse from vigorous surging action. Plugging the valve of the plunger changes it to a solid-type plunger that is used when greater surging force is necessary. Attach sufficient weight to the surge plunger to make it fall with the same speed on the downstroke as the drilling machine uses on the upstroke. The drill stem provides the weight required for the surge block. Use the following procedures for the surge block method:
- Step 1. Lower the surge plunger into the well until the water is above the top of the screen. Keep the
plunger a few ft above the screen so that it does not strike the screen while surging.
- Step 2. Start surging slowly and gradually increase the speed until the surge plunger rises and falls
without slack. With a rotary rig, lift the plunger 3 or 4 ft before dropping it. When using the sand line, control movement by using the hoist brake and clutch.
- Step 3. Continue surging for several minutes. Pull the plunger out of the well and lower the bailer or
sand pump into the screen. When the bailer rests on the sand that is pulled into the screen, check the depth of the sand by measuring it on the sand line. Bail all the sand out of the screen.
- Step 4. Repeat the surging operation and compare the quantity of sand with the first quantity. Bailout
the sand.
- Step 5. Repeat surging and bailing until little or no sand is pulled into the well. Lengthen the period of
surging as the quantity of sand removed decreases.
6. *Compressed-Air Method*. Compressed air provides rapid and effective development of wells, using an
open- or closed-well method. The standard 350-cfm compressor works for developing most wells at a
pressure of at least 100 psi. However, a higher pressure is preferable. The 250-cfm compressor pumps
water by air lift from 100 to 150 gpm, depending on the submergence and size of the pipes uses. Figure 6-4 shows the recommended sizes of pipe and air lines and the pumping rates for various sizes of wells.

If using PVC casing, ensure compressor psi output does not exceed breaking strength of casing material.

a. *Open-Well Method*. The surging cycle is established by pumping from the well with an air lift and by
dropping the air pipe suddenly to cut off the pumping. This cycle discharges large bubbles of compressed air into the screen. The submergence ratio must be 60 percent. Submergence is the extent
to which the air pipe is submerged in the water compared to the extent the pipe is between water and ground level. Work efficiency decreases rapidly as the submergence ratio drops below 60 percent. In deep wells with a considerable head and a low submergence ratio, some effective work is accomplished by shooting heads.
  Figure 6-5 shows the proper method of placing the drop pipe and airline in the well. Use a hoist line to
easily handle the drop pipe. Suspend the air pipe on the sand line. Fit a T pipe at the top of the drop pipe with a short discharge pipe at the side outlet. Wrap a sack around the air line where it enters the drop pipe to keep water from spraying around the top of the well. Discharge from the compressed air tank to the well should be the same size as or one size larger than the airline in the well. Connect a quick-opening valve in the line near the tank. A pressure hose, 15 ft long minimum is necessary for moving the drop pipe and air line up and down. Use the following procedures to start developing the well using this method:
- Step 1. Lower the drop pipe to within 2 ft of the bottom of the screen. Place the air line inside the
drop pipe with its lower end 1 ft or more above the bottom of the drop line.

Size of Eductor Pipe
Minimum Size of
(or casing if no
Pumping Rate*
Size of Well Casing if
Eductor Pipe is Used
Air Line
eductor pipe is used)
gpm
m3/day
in
mm
in
mm
in
mm
164 to 327 327 to 436 436 to 545 545 to 818
818 to 1,360
1,360 to 2,180 2,180 to 3,820 3,820 to 5,450 5,450 to 8,180
4 5 6 6 8 8
10 12 16
102 or larger 127 or larger 152 or larger 152 or larger 203 or larger 203 or larger 254 or larger 305 or larger 406 or larger
2 3
3 1/2
4 5 6 8
10 12
51 76 89
102 127 152 203 254 305
1/2
1 1
1 1/4 1 1/2
2 3 3 4
13 25 25 32 38 51 64 64
102

*Actual pumping rate is dependent on percent submergence.

- Step 2. Let air enter into the airline and pump the well until the water appears to be free of sand.
Start slowly. If all the water is suddenly removed, the casing may collapse in deeper wells, especially when using PVC pipe.
- Step 3. Close the valve between the tank and airline and pump the tank full of air to a pressure of
100 to 150 psi.
- Step 4. Lower the air line until it is about 1-ft below the drop pipe. Open the quick-opening valve so
the air in the tank rushes with great force into the well until a brief, forceful head of water emerges or shoots from the casing and from the drop pipe.
- Step 5. Pull the airline back into the drop pipe immediately after the first heavy load of air shoots
into the well. Doing so causes a reversal of flow in the drop pipe that effectively agitates the aquifer.
- Step 6. Let the well pump as an air lift for a short time and then shoot another head. - Step 7. Repeat this process until no sand shows, indicating the completion of this stage of
development.
- Step 8. Lift the drop pipe to a position 2-or 3-ft higher in the screen and follow the same procedure.
This develops the entire length of the screen a few ft at a time.
- Step 9. Return the drop pipe to its original position and shoot one or two more heads.
- Step 10. To complete the development process and thoroughly clean out any loose sand, pull the air
line up into the drop pipe, and use it as an air lift to pump the well.
b. *Closed-Well Method*. With this method, use compressed air to close the top of the well with a cap and
arrange the equipment so air pressure builds up inside the casing to force water out through the screen
openings (see Figure 6-6). Disadvantages with this method are:
(1) That valves and fittings may not be available for military field OPS. (2) The danger of forcing water upward outside of the casing. This loosens the casing and could ruin
the well by bringing clay down into the formation.
  Use the following procedures to develop a well using this method:
- Step 1. Arrange the equipment as in Figure 6-6 and turn the three-way valve to deliver air down the air
line, preferably with the air cock open. This pumps water out of the well through the discharge pipe.
- Step 2. When clear water emerges, cut off the air and let the water in the well regain its static level.
- Step 3. Listen to the air escaping through the air cock as the water rises in the casing to determine
stability. Close the air cock and turn the three-way valve to direct the air supply down the bypass to the top of the well, forcing the water out of the casing and back through the screen. This technique agitates
the sand and breaks down any bridging of sand grains. When the water is pushed to the bottom of the drop pipe, air escapes through the drop line. Air logging is prevented by keeping the drop pipe above the well screen.
- Step 4. Cut off the air supply and reopen the air cock so the water reaches the correct static level when
the air is heard escaping from the discharge pipe or when the pressure stops increasing.
- Step 5. Turn the three-way valve and direct the air supply down the airline to pump the well.
- Step 6. Repeat this process until the well is thoroughly developed. Bailing the well after development is
not usually required since the water velocity usually cleans out the sand from the well. However, if the
well was not initially bailed out thoroughly, the bailing process is required to clean out the well.
Be careful not to let the drill strike the bottom plug during well development, especially when using PVC pipe.

## 6.2 Dispersion Treatment

Dispersing agents, mainly polyphosphates, when added to drilling fluid, backwashing, jetting water, or water standing in the well, counteract the tendency of mud to stick to sand grains. These agents are procured locally on an as-need basis. Baroid Industries produces barafos, a white, granular, sodium tripolyphosphate thinner and dispersant. Chemicals such as sodium hexametaphosphate, sodium tripolyphosphate, and sodium septaphosphate are used to develop wells. Dispersants work effectively when applied at the rate of one-half lb of chemical to 100 gallons of water in the well. Let the mixture stand for about one hour before starting well development. Wetting agents, such as CON DET, increase the dispersion action of polyphosphates when added to the solution at a ratio of
1:100. Be careful when using the dispersion process because it could have an adverse reaction. The driller should make the decision whether to use dispersants.

## 6.3 Rock Development

Use this method to develop wells in rock formations. Good results are obtainable by combining jetting with airlift pumping from a limited zone isolated by inflatable packers. The objective is always to wash out fine cuttings, silt, and clay that have worked into the fissures, crevices, or pores of the rock during the drilling OPS. Openings that remain plugged reduce water flow into the well. Develop the well thoroughly to remove all obstructing material. When drilling through limestone formations, use acid to dissolve lime-like cementing material and to open up connections with joints or fissures beyond the borehole wall. However, such OPS are rare in military well drilling.

## 6.4 Well Protection And Treatment

The list below describes well protection and treatment considerations:

1. *External Preparations*. Disinfect and protect the well drilling equipment before starting the borehole.
Some other preventive measures are:
a. Stopping surface contaminants from entering the well.
b. Ensuring that the drilling water's quality is suitable. c. Cleaning and disinfecting all drilling equipment before starting a new well. d. Disinfecting the water used for drilling if a mud-based drilling fluid is used. If a synthetic drilling fluid
is used, chlorinate the fluid. However, doing so breaks down the fluid and reduces its life.
e. Circumventing possible water-quality problems by stopping potentially harmful fittings and equipment
from entering the borehole. Carefully check the list of the hardware and materials placed and left in the well.
Well casings should extend no more than 12 inches above the pump-house floor on a finalgrade elevation and not less than 12 inches above the normal anticipated flood level.

2. *Sealing Casing*. A well must be carefully protected from sewage and other contaminants that could
migrate down the well column to the aquifer and well screen. Sources of pollution could be on the surface
or in shallow perched water, unusable aquifers, and intermittently saturated beds. Carefully planning the well's location could help avoid surface pollutants. However, subsurface contaminants may not be known
until drilling starts. If this occurs, the location is no longer viable and the well is quickly sealed. Refer to Chapter 5 for details on sealing or grouting OPS and to STANAG 2885 ENGR (Edition 4) for sealing a
North Atlantic Treaty Organization (NATO) well.
  A rock well may be grouted from the lower end of the casing to the surface. Grout is placed between the
inner and outer casings and around the inner casing in a portion of the drilled borehole below the outer casing. Make sure that overburden does not seal the borehole after setting the casing.
3. *Disinfection*. All newly constructed wells should be considered contaminated from the construction process
and disinfected immediately after completion. Well-completion kits provide packages of a dry chlorinator for breaking down synthetic drilling fluids to disinfect the wells. Prepare a chlorine solution by:
- Step 1. Mixing 1 heaping tablespoon of calcium hypochlorite with water to make a thin paste. Break up
all lumps.
- Step 2. Stirring mixture into 1 quart of water. Let the mixture stand a short time. - Step 3. Pouring off the clear liquid.
  The chlorine strength of the solution is about 1 percent. One quart of the liquid is enough to disinfect
1,000 gallons of water. Larger quantities of the solution may be prepared in the same proportion and, if
placed in sealed containers (preferably glass), stored for several years without losing its effectiveness.
When storing chlorine for long periods of time the solution needs to be stored in the dark since direct sun light degrades the effectiveness of chlorine.
  Estimate the volume of water standing in the well. Pour in the corresponding ratio of solution to gallons of
water in the well (for safety, use less solution than too much solution since overchlorination could have long-term health effects if left uncorrected). Agitate the water in the well thoroughly and let it stand for several hours, preferably overnight. Flush the well to remove the entire disinfecting agent. Disinfect the
well casing by returning chlorinated water to the well during the early stage of flushing and washing the walls.
  For information on water purification and the storage, protection, monitoring, and testing of water, refer to
MCWP 4-11.6, Petroleum and Water Logistics Operations; FM 21-10/MCRP 4-11.1D, Field Hygiene and
Sanitation; and FM 10-52, *Water Supply in Theaters of Operations*.
4. *Cathodic Protection*. A sacrificial anode (see Figure 6-7) is the simplest method of protecting metal
casing from corrosion. Connect a galvanically active metal bar, such as magnesium-coated wire, to the
casing. Bury the anode bar near the casing below the water table. In this cell, ions flow to the casing through the groundwater. While the anode corrodes, the casing remains unaffected. Another method is to suspend cable (acting as the anode) into the well. The anode continues to operate and protect the casing
until it is consumed (the anode is replaced as part of continuing maintenance).
5. *Well Head and Collar*. Use the well head in the well-completion kit; otherwise, extend the casing at least
1-ft above the general level of the surrounding surface. Seal the space around the outside of the casing by
pouring a concrete platform around the casing at the surface (see Figure 6-8). To form a concrete
platform, the following bill of materials (BOM) is necessary:
a. Two 2-inch by 9-inch by 8-ft boards. Cut these in half for the walls. b. Eight 2-ft long No. 4 reinforcement bars for the comer stakes.
c. One 4- by 4-ft wire mesh. d. About 0.5 cubic yards of concrete.
Use the following procedures to make the platform:

- Step 1. Clear the site with shovels. - Step 2. Dig a 4-inch excavation. - Step 3. Construct the form. - Step 4. Place the wire mesh, snipping out the center for the casing pipe. - Step 5. Mix and pour the concrete quickly. - Step 6. Pull the wire mesh up through the concrete. - Step 7. Screed with a 2-inch by 4-inch by 8-ft board (ensure minor slope away from casing).
Mission requirements may cause variations in dimensions and design.

If a container is unavailable to mix the concrete, construct a mortar box using the following materials:

a. One 4-ft by 8-ft by 1/2-inch piece of plywood for the base.
b. Four 2-inch by 6-inch by 8-ft boards for the walls. c. One 2-inch by 4-inch by 8-ft screed beam.
When mixing concrete, add the water slowly. Use 5 gallons of water per sack of concrete. Mix it with a hoe and place the concrete quickly.

  The upper surface of this slab and its immediate surroundings should be gently sloping so water drains
away from the well. Place a drain around the outer edge of the slab and extend it to a discharge point that is far away from the well. A well with pipe casing should have a sanitary seal at the top that fills the space between the pump pipe and the well casing. This device consists of a bushing or packing gland that makes a watertight connection.

## 6.5 Well-Completion Report

Figure 6-9 is an example of a military water-well-completion summary report (DD Form 2680). This form is used to update the world-wide DOD WRDB after completion of all well drilling OPS. Fill out the form and send it to the address on the form. DD Form 2680 is in the back of this manual for reproduction and use.

INTENTIONALLY BLANK

## Chapter 7 Pumps 7.1 Fundamentals

The list below describes the fundamentals of pumps:

1. *Pump Types*. Pumps are classified according to use (for shallow or deep wells), design (variable or
positive displacement), or method of operation (rotary, reciprocating, centrifugal, jet, or airlift). This
chapter deals with shallow-well and deep-well pumps. Shallow-well pumps (suction-lift pumps) are
normally installed above ground, on or near the top of the well casing. Deep-well pumps are installed in the well casing with the pump inlets submerged below the pumping level. These inlets are always under a positive head and do not require suction to move or pump the water.
2. *Selection Criteria*. Consider the following items when selecting a pump:
a. Size of the well. b. Quantity of water to be pumped. c. Drawdown and pumping levels. d. Type of available power. e. Yield of the well. f. Estimated total pumping head. g. Host nation needs. h. Ease of maintenance.
Well yield is frequently overlooked when selecting a pump for small wells. Installing a pump that handles a large discharge capacity may either temporarily drain a small well or exceed the maximum possible suction lift. Therefore, pumping requirements and well characteristics must be matched to determine the optimum pump for each installation. Figure 7-1 provides a general guide for use in pump selection. Military well drillers deploying with well-completion kits normally use the deep-well submersible pumps that are supplied with the kits.

## 7.2 Shallow-Well Pumps

These pumps are limited to the depth from which they lift water. At sea level, the practical limit is 22 to 25 ft for most pumps. This value decreases about 1 ft for each 1,000-ft increase in elevation above sea level. The operative principle of a shallow-well pump is similar to drinking through a straw. A partial vacuum is created, and the difference between the pressure inside the straw and the liquid outside the straw forces the liquid upward to a new equilibrium.

A pump exhausts air from the intake line, thus lowering the pressure on the intake side below atmospheric pressure. The atmospheric pressure on the water in the well then forces the water up through the suction line into the pump. The atmospheric pressure is the only force available to lift water to the pump. At sea level, the force is about 14.7 psi (about 34-ft of water). The maximum is never reached because pumps are not 100 percent efficient and because other factors (i.e., water temperature and friction or resistance to flow in the suction pipe) reduce the suction lift. Since a partial vacuum is required in the suction line, the line must be airtight if the pumps are to function properly. Threaded joints must be carefully sealed with pipe-joint compound and all connections to the pump must be tight. The list below describes various types of shallow-well pumps:

| Usual                               | Type of Pump    | Practical    |
|-------------------------------------|-----------------|--------------|
| Suction                             |                 |              |
| Usual                               |                 |              |
| Well-                               | Pressure        |              |
| Lift                                | Heads           | Pumping      |
| Depths                              |                 |              |
| 22 to 26 -ft                        |                 |              |
|                                     |                 |              |
| 22 to 25 -ft                        |                 |              |
| Reciprocating:                      |                 |              |
| 1. Shallow well                     |                 |              |
|                                     |                 |              |
| 2. Deep well                        |                 |              |
| 22 to 26 -ft                        |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| Up to 600 -ft                       |                 |              |
| 100 to 200 -ft                      |                 |              |
|                                     |                 |              |
| Up to 600 -ft                       |                 |              |
| above cylinder                      |                 |              |
| 1. Positive action                  |                 |              |
| 2. Discharge against variable       |                 |              |
| heads                               |                 |              |
| 3. Pumps water containing           |                 |              |
| sand and silt                       |                 |              |
| 4. Especially adapted to low        |                 |              |
| capacity and high lifts             |                 |              |
|                                     |                 |              |
| 10 to 20 -ft                        |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 28 -ft                              |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 50 to 300 -ft                       |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 50 to 400 -ft                       |                 |              |
|                                     |                 |              |
| 100 to 150 -ft                      |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 100 to 200 -ft                      |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 100 to 800 -ft                      |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 80 to 900 -ft                       |                 |              |
|                                     |                 |              |
| 1. Smooth, even flow                |                 |              |
| 2. Pumps water containing           |                 |              |
| sand and silt                       |                 |              |
| 3. Pressure on system is even       |                 |              |
| and free from shock                 |                 |              |
| 4. Low-starting toque               |                 |              |
| 5. Usually reliable and good        |                 |              |
| service life                        |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| Same as shallow-well turbine        |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 1. Same as shallow-well turbine     |                 |              |
| 2. Easy to frost proof installation |                 |              |
| 3. Short pump shaft to motor        |                 |              |
| Centrifugal:                        |                 |              |
| 1. Shallow well                     |                 |              |
|                                     |                 |              |
| a. Straight                         |                 |              |
| centrifugal (single                 |                 |              |
| stage)                              |                 |              |
|                                     |                 |              |
| b. Regenerative                     |                 |              |
| vane turbine type                   |                 |              |
| (single impeller)                   |                 |              |
|                                     |                 |              |
| 2. Deep well                        |                 |              |
|                                     |                 |              |
| a. Vertical line                    |                 |              |
| shaft turbine                       |                 |              |
| (multistage)                        |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| b. Submersible                      |                 |              |
| turbine                             |                 |              |
| (multistage)                        |                 |              |
|                                     |                 |              |
| 20 -ft                              |                 |              |
| maximum                             |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 28 -ft                              |                 |              |
| maximum                             |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| Impellers                           |                 |              |
| submerged                           |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| Pump and                            |                 |              |
| motor                               |                 |              |
| submerged                           |                 |              |
| Jet:                                |                 |              |
| 1. Shallow well                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 2. Deep well                        |                 |              |
|                                     |                 |              |
| 15 to 20 -ft                        |                 |              |
| below ejector                       |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 15 to 20 -ft                        |                 |              |
| below ejector                       |                 |              |
|                                     |                 |              |
| 80 to 150 -ft                       |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 80 to 150 -ft                       |                 |              |
|                                     |                 |              |
| 1. High capacity at low head        |                 |              |
| 2. Simple in operation              |                 |              |
| 3. Does not have to be installed    |                 |              |
| over the well                       |                 |              |
| 4. No moving parts in well          |                 |              |
|                                     |                 |              |
| Same as shallow-well jet            |                 |              |
|                                     |                 |              |
| Up to 15 to 20                      |                 |              |
| -ft below                           |                 |              |
| ejector                             |                 |              |
|                                     |                 |              |
|                                     |                 |              |
|                                     |                 |              |
| 25 to120 -ft,                       |                 |              |
| 200 -ft                             |                 |              |
| maximum                             |                 |              | 1. Positive action 2. Discharge constant under variable heads 3. Efficient operation 1. Same as shallow-well rotary 2. Only one moving pump device in well

*Practical suction at sea level reduces lift 1-ft for each 1,000-ft above sea level

| Advantages                             |
|----------------------------------------|
| 1. Pulsating discharge                 |
| 2. Subject to vibration and noise      |
| 3. Maintenance cost may be high        |
| 4. May cause destructive pressure      |
| if operated against closed valve       |
| 1. Best suited for                     |
| capacities of 5 to 25                  |
| gpm against moderate                   |
| to high heads                          |
| 2. Adaptable to hand                   |
| operation                              |
| 3. May be installed in                 |
| very small diameter                    |
| wells (2-inch casing)                  |
| 4. Pump must be set                    |
| directly over well                     |
| (deep well only)                       |
|                                        |
| 1. Loses prime easily                  |
| 2. Efficiency depends on operating     |
| under design heads                     |
| and speed                              |
|                                        |
| Same as straight centrifugal           |
| except maintains priming easily        |
|                                        |
|                                        |
| 1. Efficiency depends on               |
| operating under design head and        |
| speed                                  |
| 2. Requires straight well large        |
| enough for turbine bowl and            |
| housing                                |
| 3. Lubrication and alignment of        |
| shaft critical                         |
| 4. Abrasion from sand                  |
|                                        |
| 1. Repair to motor or pump             |
| requires pulling from well             |
| 2. Sealing of electrical equipment     |
| from water vapor critical              |
| 3. Abrasion from sand                  |
|                                        |
| Very efficient pump for                |
| capacities above 50                    |
| gpm and heads up to                    |
| about 150--ft                          |
|                                        |
| Reduction in pressure                  |
| with increased                         |
| capacity not as severe                 |
| as straight centrifugal                |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
| Difficulty with waling                 |
| has caused                             |
| uncertainty as to                      |
| service life to date                   |
|                                        |
| 1. Capacity reduces as lift            |
| increases                              |
| 2. Air in suction or return line stops |
| pumping                                |
|                                        |
|                                        |
| Same as shallow-well jet               |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
| The amount of water                    |
| returned to ejector                    |
| increases with                         |
| increased lift- 50 % of                |
| total water pumped at                  |
| 50-ft lift and 75% at                  |
| 100-ft lift                            |
|                                        |
| 1. Subject to rapid wear it water      |
| contains sand or silt                  |
| 2. Wear of gears reduces               |
| efficiency                             |
|                                        |
| Same as shallow-well rotary            |
| except no gear wear                    |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
|                                        |
| A cutless rubber stator                |
| increases life of pump;                |
| flexible drive coupling                |
| is weak point in pump;                 |
| best adapted for low                   |
| capacity end high                      |
| heads                                  |

1. *Pitcher-Spout Hand Pump*. This is a surface-mounted, reciprocating or single-acting piston pump (see
Figure 7-2). It pumps water up to depths of 24-ft. The pump has a hand-operated plunger that works in a cylinder designed to be set on top of the well casing. The suction pipe screws into the bottom of the cylinder. The plunger has a simple ball valve that opens on the downstroke and closes on the upstroke. Usually, a check valve at the lower end of the cylinder opens on the upstroke of the pump and closes on
the downstroke. Continuous upstroke and downstroke actions result in a pulsating flow of water out of the discharge pipe. By lifting the pump handle as high as possible, the check valve (lower end of the cylinder) tilts when the plunger is forced down on top of the valve. Tilting the check valve allows the pump and suction line to drain.
  To reprime the pump after draining, pour water in the cylinder from the top of the pump. To maintain the
pump, renew the plunger, check the valve leathers, and clean the suction pipe. Clean the suction pipe
when it becomes clogged with sand, gravel, or other material. The pump is noisy and the handle may fly up when released during the downstroke.
  A hand pump is the preferred pump choice during HCA and/or FHA projects as it pumps efficiently from
shallow wells or ponds. Because it does not use power, it is also ideal for pumping water in locations without power or in an emergency during power outages.
2. *Rotary Pump*. These pumps use a system of rotating gears (see Figure 7-3) to create suction at the inlet
and force a water stream out of the discharge. The gears' teeth move away from each other at the inlet port. This action causes a partial vacuum and the water in the suction pipe rises. In the pump, the water is
carried between the gear teeth and around both sides of the pump case. At the outlet, the teeth moving together and meshing causes a positive pressure that forces the water into the discharge line.
  In a rotary gear pump, water flows continuously and steadily with very small pulsations. The pump size
and shaft rotation speed determine how much water is pumped per hour. Gear pumps are generally intended for low-speed operation. The flowing water lubricates all internal parts. Therefore, the pumps should be used for pumping water that is free of sand or grit. If sand or grit does flow through the gears, the close-fitting gear teeth wear, thus reducing pump efficiency or lifting capacity.
3. *Centrifugal Pump*. These are variable displacement pumps in which water flows by the centrifugal force
transmitted to the pump in designed channels of a rotating impeller (see Figure 7-4). A closed case, with a spiral-shaped channel for the water and a discharge opening, surrounds the impeller. The channel gradually widens towards the outlet opening. As water flows through the channel, speed decreases and pressure increases. The hydraulic characteristics of the pump depend on the dimensions and shape of the
water passages of the impeller and the case. The centrifugal pump works as follows:
a. Water enters the pump at the center of the impeller and is forced out by centrifugal force (The pump
and suction pipe may need to be full of water before starting the pump).
b. The expelled water forces the water in the casing out through the discharge pipe, producing a partial
vacuum in the center.
c. Atmospheric pressure acts on the surface of the water in the well and forces more water up the suction
pipe and into the impeller to replace the expelled water.
The list below describes additional considerations:

a. *Head*. Head is the pressure against which a pump must work the suction-lift and friction losses and the
system pressure that the pump must develop. If the head is increased and the speed is unchanged, the
flow rate decreases. To increase the flow rate, increase the speed or decrease the head. If the head is increased beyond the pump's (shutoff head) capacity, water is not pumped. The impeller only churns
the water inside the case; the energy expended heats the water and the pump. If such action continues,
enough heat may develop to boil the water and generate steam causing the impeller to rotate in vapor rather than water. With no coolant, the bearings seize, resulting in severe pump and possible motor damage.
b. *Connections*. Several pumps may be required to meet head or flow requirements. Connect the pumps
either in series or in parallel. If two centrifugal pumps are connected in series (the discharge of the first
connected to the suction of the second), the discharge capacity stays the same. However, the head capacity is the sum of both pumps' head capacities. The increased head capacity is only available as discharge head; no appreciable increase is gained in suction lift. The same effect is obtainable by using a multistage pump that contains two or more impellers within one casing.
  If two centrifugal pumps are connected in parallel (both suctions are connected to the intake line and
both discharges connected to the discharge line), the discharge head is the same as that of the
individual pumps and the discharge capacity is close to the sum of the capacities of both pumps (the increased flow rates result in extra friction losses that prevent the combined flows from being the exact
sum of the two pumps).
4. *Self-Priming Pump*. This pump has a priming chamber that makes repriming unnecessary when the pump
is stopped for any reason other than an intentional draining. The pump is mounted on a frame with and driven by a two-cylinder, three-horsepower military standard engine (see Figure 7-5). The unit is closecoupled. The impeller is secured to an adapter shaft that is fastened and keyed to the engine stub shaft. A self-adjusting mechanical seal prevents water from leaking between the pump and the engine. The pump is
designed for optimum performance with a suction lift of 10-ft. The pump is operable at greater suction lifts, but the capacity and efficiency of the unit are reduced proportionately.
a. *Installation*. Install the pump as close to the source of water supply as possible to minimize the required
suction lift. Install full-sized suction piping and keep friction losses as low as possible by using the least possible number of pipe fittings (i.e., elbows, bents, unions). To ensure that joints do not leak use pipe cement or teflon tape on all joints. If a suction hose is used, try to ensure that the hose is as airtight as possible. If removing the suction, discharge piping, or hose frequently, make the connections with unions to reduce wear on the pump housing.
b. *Priming*. To prime the pump, remove the priming plug on top of the pumping case, and pour water into
the pump case to the discharge-opening level. Failure to fill the priming chamber may prevent priming. If the pump takes longer than 5 minutes to prime, a mechanical problem exists. A self-priming pump is normally primed from a 9-ft suction lift in 2 minutes or less, depending on the length and size of the suction pipe. If a valve is used in the discharge line, open it wide during priming. If the pump fails to prime, look for the following:
(1) Plugged priming hole (2) Air leak in suction pipe or hose (3) Collapse of lining suction hose
(4) Plugged end of suction pipe or suction strainer (5) Lack of water in pump housing (6) Clogged, worn-out, or broken impeller (7) Worn or damaged seal.

## 7.3 Deep-Well Pumps

The list below describes various deep-well pumps:

1. *Submersible Pump*. This is a centrifugal pump closely coupled with an electric motor that operates
underwater.  The pump is typically multistage containing two or more impellers (depending on head
requirements) housed in a bowl assembly. Because the system is designed for underwater OPS, it has a waterproof electric motor, watertight seals, electric cables, and connections. The motor is located beneath the bowl assembly with the water intake screen between the two units.
  Military well-completion kits contain the submersible pump (see Figure 7-6). The pump produces 50 gpm
at 600 ft and is powered by a 15 horsepower, 460-volt, 3-phase electric motor. The pump comes with 700 ft of electrical conductor cable and 660 ft of 2-inch drop hose that supports the pump and brings the water
to the surface distribution system. Currently, the submersible pump is the standard in deep-well, highproduction systems.
Don't handle live electrical wires when wet or while standing in water. Do not step on exposed electrical cables.

The submersible pump is reliable and has the following characteristics:

a. Motors, cables, and seals have very low maintenance requirements. b. Noise levels are reduced because the motor is located in the well. c. Motor operates at a cooler temperature because it is submerged. d. System does not require long drive shafts and bearings, so maintenance problems and deviations in
vertical well alignment are not critical factor when using this pump.
The main disadvantage with the pump is that the entire pump and motor assemblies require removal from the well if repairs or services are necessary.

2. *Turbine Pump*. The turbine (line shaft) pump is a shaft-driven, centrifugal pump. The pump is hung in a
well at the lower end of a string of pipe called the column pipe. The shaft, which drives the pump, runs through the column pipe and extends from the pump to the ground surface where it is connected to a pump-head assembly. Bearings in the column pipe are used to stabilize the shaft. The turbine pump (see Figure 7-7) is a multistage pump containing several impellers or bowl assemblies. The main advantage to
the turbine pump is the accessibility to the power source. The power source is either a hollow-shaft electric motor or a reciprocating engine connected by a right-angle drive and is located above ground. The main disadvantages are maintenance requirements for the shaft and bearings and the requirement that the well is vertical with no deviations for installation.
3. *Helical-Rotor Pump*. This pump is a positive-displacement-, rotary-screw-, or progressing-cavity-type
pump (see Figure 7-8). The pump is designed for relatively low-capacity, high-lift wells that are 4-inches or larger in diameter. The main elements of the pump are a highly polished, stainless-steel helical rotor, a
single-thread worm; and an outer rubber stator. The rotor is located in the stator. During the rotation process, the rotor forces a continuous stream of water forward along the cavities in the stator producing a
uniform flow. The helical-rotor pump is designed to produce 50 gpm at 1,800 rpm against a 250-ft head.
4. *Jet Pump*. This pump is a combination of a surface centrifugal pump, down-hole nozzle, and venturi
arrangement (see Figure 7-9). It is used in small diameter wells that require a lift of 100-ft or less. The pump supplies water under pressure to the nozzle. The increase in velocity at the nozzle results in a decrease in pressure at that point, which in turn draws water through the foot valve into the intake pipe. The combined flow then enters the venturi where the velocity is gradually decreased and the pressure head is recovered. The excess flow is discharged at the surface through a control valve, which also maintains the required recirculating flow to the nozzle.
  A jet pump's efficiency is low compared to an ordinary centrifugal pump. However, other features make
the jet pump a desirable pump. They are:
a. Adaptability to wells as small as 2-inches in diameter b. Easy accessibility to all moving parts at the ground surface c. Simple design resulting in low purchase and maintenance costs.

## 7.4 Air-Lift Pumps

The list below describes air-lift pump considerations:

1. Principle. Water is readily pumped from a well using an air-lift pump. There are no air-lift pumps in the
military supply system; however, in the field, improvisation of a pump using compressed air and the
proper piping arrangement is possible. The assembly consists of a vertical discharge (eductor) pipe and a smaller air pipe. Both pipes are submerged in the well below the pumping level for about two-thirds of the
pump's length. The compressed air goes through the air pipe to within a few ft of the bottom of the eductor pipe and is then released inside the eductor pipe. A mixture of air bubbles and water forms inside the eductor pipe. This mixture flows up and out the top of the eductor pipe. The pumping action that causes water to rise as long as compressed air is supplied is the difference in hydrostatic pressure inside
and outside the pipe resulting from the lowered specific gravity of the mixed column of water and air bubbles. The energy operating the air lift is contained in the compressed air and released in the form of bubbles in the water. Figure 7-10 shows the operating air-lift principle.
Air and fluids under pressure may cause injury. Make sure all air couplings are tight and that lines and hoses are in good condition.

  Arrange an air lift with the air pipe inside the eductor pipe for both test pumping wells and well
development (see Figure 7-11). The well casing is useable as the eductor pipe. However, to pump sand and mud from the bottom of a well during well development and completion, use a separate eductor pipe. This type of pump is also useful in wells that, because of faulty design, produce sand with the water. This
condition quickly creates excessive wear on most pumps. By setting the educator pipe to the bottom of the
screen, sand is removed before it fills the screen.
2. *Installation Design.*
a. *Submergence*. Submergence is the proportion (percentage) of the length of the air pipe that is
submerged below the pumping level. Use the following formula and Figure 7-12 below to determine submergence percentage:
y x 100 x % submergence =    where:   x   = vertical distance from A to C. y   = vertical distance from C to D.
a. *Air Pressure*. To calculate the required air pressure to start the air lift, the length of air pipe
submerged below the static level must be known. The area from point B to point D is the starting air pressure (see Figure 7-12). Divide the area from point C to D (Figure 7-12) by 2.31
(constant/conversion factor) to get the required air pressure (psi).
b. *Compressors*. The 350-cfm compressor on military drilling rigs is sufficient for operating an air
lift. With a submergence of 60 percent, a lift not exceeding 50-ft and the compressor delivering 350-cfm of air, a well is able to pump at over 200 gpm. If more air is needed, use another compressor in parallel. The maximum pressure that the compressor produces is 200 psi, which is enough to start an airlift with about 420-ft of air pipe submerged.


Operate compressors upwind of the drilling rig. Otherwise, dust could damage the equipment.

d. Correct Air Amounts. For efficiency, the compressor must deliver the correct amount of air. Too much
air causes excessive friction in the pipe lines and waste of air from incomplete expansion in the discharge pipe. Too little air results in a reduced yield and a surging, intermittent discharge. To
calculate air-compressor requirements (see Figure 7-13).
e. Performance and Efficiency. The performance and efficiency of an air lift vary greatly with the percent
of submergence and the amount of lift. Generally, a submergence of 60 percent or more is desirable. If
a well has a considerable pumping-level depth, use a lesser submergence percent. However, if the
submergence is too low, the air lift does not operate. See Figure 7-14 for performance data for air-lift pumps corresponding to different submergence conditions and lifts. The values are for properly proportioned air and eductor pipes with minimum frictional losses. The efficiencies indicated in terms of gallons of water per cubic ft of air probably cannot be fully attained in military field OPS.

| Total Depth    | Submergence    |
|----------------|----------------|
| (ft)           | (percent)      |
| Up to 50       | 66 to 70       |
| 50 to 100      | 55 to 66       |
| 100 to 200     | 50 to 55       |
| 200 to 300     | 43 to 50       |
| 300 to 400     | 40 to 43       |
| 400 to 500     | 33 to 40       |

f. Foot Piece. For best efficiency, the end of the air pipe requires a ft piece (see Figure 7-11). This device
breaks the air into small streams so that the bubbles formed are as small as possible. Make a ft piece by
drilling numerous small holes in a short section of pipe.
g. Discharge Pipe. Figure 7-14 illustrates an approximated discharge-pipe length. Lower submergence
than those shown result in a lower pumping efficiency. The planned pumping rate must not cause an excessive drop in the water level as it reduces the submergence. The two chief losses in the discharge pipe are air slipping through the water and the water friction in the discharge line. As the velocity of discharge increases, slippage decreases and friction increases. Eductor intake loss occurs at the lower end of the pipe due to friction and to the energy required to accelerate the flow of water into the pipe.

| Submergence    | Lift      | Rating    |
|----------------|-----------|-----------|
| (ft)           | (percent) | (percent) |
| 25             | 54        |           |
| 68             |           |           |
| 76             |           |           |
| 46             |           |           |
| 32             |           |           |
| 24             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 50             | 51        |           |
| 65             |           |           |
| 72             |           |           |
| 49             |           |           |
| 35             |           |           |
| 28             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 100            | 47        |           |
| 60             |           |           |
| 67             |           |           |
| 53             |           |           |
| 40             |           |           |
| 33             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 150            | 43        |           |
| 55             |           |           |
| 62             |           |           |
| 57             |           |           |
| 45             |           |           |
| 38             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 200            | 41        |           |
| 52             |           |           |
| 59             |           |           |
| 59             |           |           |
| 48             |           |           |
| 41             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 250            | 39        |           |
| 49             |           |           |
| 56             |           |           |
| 61             |           |           |
| 51             |           |           |
| 44             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 300            | 37        |           |
| 47             |           |           |
| 53             |           |           |
| 63             |           |           |
| 53             |           |           |
| 47             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 350            | 36        |           |
| 46             |           |           |
| 50             |           |           |
| 64             |           |           |
| 55             |           |           |
| 50             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 400            | 35        |           |
| 43             |           |           |
| 48             |           |           |
| 65             |           |           |
| 57             |           |           |
| 52             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 450            | 34        |           |
| 42             |           |           |
| 47             |           |           |
| 66             |           |           |
| 58             |           |           |
| 53             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 500            | 34        |           |
| 41             |           |           |
| 46             |           |           |
| 66             |           |           |
| 59             |           |           |
| 54             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 550            | 34        |           |
| 40             |           |           |
| 45             |           |           |
| 66             |           |           |
| 60             |           |           |
| 55             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 600            | 33        |           |
| 40             |           |           |
| 44             |           |           |
| 67             |           |           |
| 60             |           |           |
| 56             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 650            | 33        |           |
| 39             |           |           |
| 43             |           |           |
| 67             |           |           |
| 61             |           |           |
| 57             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
| 700            | 33        |           |
| 39             |           |           |
| 43             |           |           |
| 67             |           |           |
| 61             |           |           |
| 57             |           |           |
| Minimum        |           |           |
| Best           |           |           |
| Maximum        |           |           |
Starting
(ft)
Air
Gallons
of Water
Total
Length
Pressure
(psi)
(per
cubic
Cubic
Feet
of Air
(per
ft of air)
gallon
of
of
Air
Line
(ft)
water)
29 53 79
13 23 34
4.55 8.34
14.30
0.22 0.12 0.07
54 78
104
52 93
129
23 40 56
2.50 4.35 6.57
0.40 0.23 0.15
102 143 179
89
150 203
38 65 88
1.43 2.70 3.70
0.70 0.37 0.27
189 250 303
113 183 245
49 79
106
1.05 2.04 2.70
0.95 0.49 0.37
263 333 395
139 216 288
60 94
125
0.85 1.54 1.89
1.18 0.65 0.53
339 416 488
160 240 318
69
104 138
0.71 1.21 1.45
1.41 0.83 0.69
410 490 568
176 266 339
76
115 147
0.60 0.96 1.18
1.67 1.04 0.85
476 566 639
197 287 350
85
124 151
0.53 0.80 0.94
1.88 1.25 1.06
547 637 700
215 302 369
93
130 160
0.48 0.69 0.79
2.07 1.45 1.26
615 702 769
232 326 399
100 141 173
0.44 0.61 0.68
2.27 1.65 1.48
682 776 849
258 348 426
112 150 184
0.41 0.54 0.60
2.46 1.85 1.66
758 848 926
283 367 450
123 159 195
0.38 0.49 0.54
2.65 2.05 1.86
833 917
1,000
296 400 471
128 173 204
0.36 0.45 0.49
2.81 2.25 2.06
896
1,000 1,071
320 416 490
139 180 212
0.34 0.42 0.44
2.94 2.40 2.26
962
1,066 1,140
345 448 528
149 194 228
0.33 0.39 0.42
3.00 2.55 2.40
1,045 1,148 1,228

INTENTIONALLY BLANK

## Chapter 8 Well-Performance Testing Procedures 8.1 Testing Pumps

The permanent pump is normally used for pump testing. If using a temporary unit, it must be adequate to draw down the water and hold it at a prescribed flow rate for a period of hours. This test determines the specific capacity of the well. Estimate the yield of a small well by bailing water from the well rapidly if no pump is available. To estimate the gpm of the well, the bailer's volume must be known and the number of times per minute the bailer is brought up full is counted. Accurately measuring drawdown is not possible during the test because the water level constantly fluctuates. The list below details additional information on testing wells:

1. *Permanent Wells*. When possible, use two different testing procedures if a pump is available, depending
on the intended use of the well and the available testing time. If the well is permanently installed, a detailed test is required. Measure the static water level in the well before testing and measure the
drawdown during the test. Conduct the test as follows:
a. Pump at a rate that lowers the water in the well about one-third of the maximum drawdown possible
(one-third the distance from the static water level to the top of the well screen) or about one-third of
the rated capacity of the pump.
b. Monitor and adjust the flow rate early in the test because as the drawdown increases the flow rate
decreases.
c. Continue pumping at a constant flow rate until the drawdown remains constant (about 1 to 4 hours).
d. Record the flow rate, drawdown, and testing time. Initially, take readings rapidly and then spread out the
readings as the test continues. A reading schedule that doubles the time between readings is preferable. The
recommended schedule is as follows: 0 (at the start of the test) 30 seconds, 1 minute, 2 minutes, 4 minutes, 8 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, and so forth.
e. Establish the desired, constant flow rate quickly. Record the exact time of each reading (not the
intended or scheduled time). After the drawdown stabilizes (1 to 4 hours), the pumping rate increases to a new, constant flow rate, which produces two-thirds of the capacity of the pump. Do not stop the
pump between these test segments.
f. Repeat the measurements, noting the exact time that the new flow rate is started. Try to follow the
above reading schedule, starting from the time the flow rate is increased. When the drawdown stabilizes, increase the pumping rate to produce the maximum drawdown or about 90 percent of the maximum capacity of the pump. Conduct another reading schedule until the pumping level stabilizes.
  The above procedure may require modification depending on well requirements and local site conditions.
However, the precision and accuracy of the measurements taken shall not change. Test results shall
become a part of the permanent records. The results are useful for evaluating the efficiency of the well in
the future and for determining the need for well rehabilitation. Calculating the gpm per ft of drawdown gives the capacity of the well. This information is used to estimate production and to regulate the pump's flow rate to prevent dewatering of the well and possible pump damage.
2. *Temporary Wells*. Conduct a single-stage test rather than the step drawdown test. To establish the flow
rate, conduct a 1- to 2-minute test to determine the gpm per ft of drawdown. Let the well return to the original static water level before testing (about 1 hour). Select a flow rate that produces about two-thirds of the available drawdown, but does not reach more than 90 percent of the pump's capacity. Conduct the
test as described above, but with only one segment. When the drawdown stabilizes for the selected flow
rate, stop the test.
3. *Methods*. Refer to Chapter 7 for a description of pumps used in testing and well production.
a. *Submersible-Pump Method*. Use the submersible pump in well-completion kits to pump test the water
well. Set the pump deep enough to attain the maximum pumping rate and drawdown. When testing a well with a screen, set the suction of the pump above the top of the screen to prevent lowering the water level below the screen. When testing a well without a screen, try not to dewater the production part of the aquifer. For proper testing, a reliable power source is required so that testing is not interrupted. The power must be sufficient to drive the pump at a rated speed so that full capacity is
developed.
b. *Air-Lift Method*. This method is sometimes best for military field OPS, especially if the well may
produce sand that could damage or reduce the life of a submersible pump. An air-lift pump has two major problems. Air turbulence could make drawdown measuring difficult and entrained air may cause considerable error in measuring the flow rate. After constructing an air-lift pump, check the pump capacity against the expected well yield. To conduct the test, set the pump according to the readings in
Figure 7-13.
An air compressor that puts out 350 cfm at 200 psi is suitable for performing most air-lift pumping OPS. To determine the amount of air needed for pumping water, use the following equation or refer to Figure 8-1.

T
Q = v(60)

where:
V = free air (actual) required to raise one gallon of water, in cubic ft.

h = total lift, in ft. log=  logarithm-c value. H = operating submergence, in ft. C = constant (see Figure 8-2).

The pressure required to start pumping is equal to the depth of water over the submerged end of the air pipe. After pumping has started the water in the well draws down to a working level. The air pressure required is the total lift, in ft, from the working water level plus the friction loss in the airline. Conduct the test and try to measure flow rate and drawdown quickly. Pumping creates turbulence in the well. Use the electric-line method (Paragraph 8.2) to try and measure drawdown. Because of entrained air, use the measured-container method (Paragraph 8.3) to obtain flow-rate measurements.

## 8.2 Measuring Water Level

The list below describes water level measuring methods:

1. *Electric-Line Method*. Water levels are measured accurately with a two-conductor, battery-powered
indicator known as a Sounder (see Figure 8-3). Well drilling units should be equipped with a well Sounder. The Sounder is a battery and a meter connected in series. When the upper wire on the tip of the Sounder touches the water in the well, the circuit completes and the meter gives a steady reading. Measure the amount of wire in the well to determine the depth to the water level. The wire is marked at 5-ft intervals for easy measuring.
2. *Tape Method*. Use this method to measure the depth to the static level in a shallow well. Conduct this test
as follows:

Constant
Submergence
(percent)
366
75
358
70
348
65
335
60
318
55
296
50
272
45
246
40
216
35

- Step. 1. Chalk one end of a weighted steel tape with carpenter's chalk. Lower the tape (see Figure 8-4)
into the well to a depth of 1 or 2 ft past the chalk (An alternative to chalk is a soluble felt-tip marker)
- Step. 2. Measure the wetted length of the tape and subtract the amount from the total length lowered
below the reference point to obtain the water depth. This test is accurate to within 0.01 ft.

## 8.3 Measuring Discharge Rate

The list below describes discharge rate measuring methods:

1. *Measured-Container Method*. The flow rate from a well or pump is determined by measuring the time
required to fill a container with a known volume. With this method, use small containers for early measurements and large containers for later measurements. Also, use an instrument, such as a stop watch,
for accurate time measurements. Use the following equation:
V + = 43 34)] C[log(H h
where: Q = flow rate, in gpm. v = volume, in gallons. T   = time required to fill container, in seconds.

2. *Flow-Meter Method*. A turbine-type flow meter gives an acceptable flow-rate reading. These meters are
used by civilians. A totalizer-type water meter is also acceptable when the yield is low. Use these meters
to measure the total gallons pumped and determine the flow rate. To do this, record the number of gallons that flow within a set amount of time and compute the flow rate.
3. *Open-Pipe Method*. With this method, the pipe is fully open and the distance the water stream travels
parallel to the pipe at a 12-inch vertical drop is measured (see Figure 8-5). Use the following procedure:
- Step 1. Measure the ID of the pipe and the distance the stream travels parallel to the pipe at a 12-inch
vertical drop. The results are in inches.
- Step 2. Estimate the flow from the pipe diameter and the distance the stream travels (see Figure 8-6).
The results are in gpm.
For partially filled pipes, measure either the water depth or the freeboard. Divide the diameter by the water depth to get a percentage ratio. Measure the stream as above and calculate the discharge. The actual discharge is, approximately, the value for a full pipe of the same diameter multiplied by the correction factor from (see Figure 8-7).

Horizontal Distance
Pipe
(inches)
Diameter
(inches)
12
14
16
18
20
22
24
26
28
30
2
41
48
55
61
68
75
82
89
96
102
3
90
105
120
135
150
165
180
195
210
225
4
150
181
207
232
258
284
310
336
361
387
6
352
410
470
528
587
645
705
762
821
880
8
610
712
813
915
1,017
1,119
1,221
1,322
1,425
1,527
10
960
1,120
1,280
1,440
1,600
1,760
1,930
2,080
2,240
2,400
12
1,378
1,607
1,835
2,032
2,286
2,521
2,760
2,980
3,210
3,430
|   Percent  |   Factor  |   Percent  |   Factor  |
|------------|-----------|------------|-----------|
|         5  |     0.981 |        55  |     0.436 |
|        10  |     0.948 |        60  |     0.375 |
|        15  |     0.905 |        65  |     0.312 |
|        20  |     0.858 |        70  |     0.253 |
|        25  |     0.805 |        75  |     0.195 |
|        30  |     0.747 |        80  |     0.142 |
|        35  |     0.688 |        85  |     0.095 |
|        40  |     0.627 |        90  |     0.052 |
|        45  |     0.564 |        95  |     0.019 |
|        50  |     0.5   |       100  |     0     |

## Chapter 9 Cold Weather Well Construction 9.1 Considerations

The list below describes cold weather considerations:

1. *Cold Weather Water Supply*. Supplying water for OPS or bases in cold regions requires careful planning
due to the harsh climate and ground conditions. Potable water is widespread at the surface in some cold
regions, but is uncommon in more arid cold regions. Locally, surface water may be melted from ice or pumped from unfrozen lakes or glacial-melt pools. Many surface sources are only dependable during the summer months, leaving potential problems in supplying water throughout the year. More dependable, year-round supplies of groundwater may be developed through wells in relatively shallow, unfrozen strata (see Figure 9-1) and from wells that fully penetrate the permafrost.
  Permanently frozen rock and soil are widespread in seasonally or permanently frozen areas. This condition
restricts groundwater development because some of the groundwater is permanently frozen and not available. The frozen zones, which vary in thickness from a few ft to 2,000 ft, are impermeable aquicludes
and inhibit the upward movement of unfrozen groundwater. The difficulty of obtaining water increases
northward as the permafrost thickens and becomes colder and more continuous.
2. *Discontinuous Permafrost*. In this zone, permafrost is thin and may be absent on the south slopes of hills,
in valley bottoms containing permeable alluvial material (sand and gravel), and under surfaces that are
cleared of vegetation (e.g., airport runways, farmlands, forest fire scars, and logging tracts). Obtain information from local sources regarding springs (icings), existing wells, unfrozen zones, and caves used for storage. Consider obtaining water from surface sources before drilling and developing wells in the permafrost zone. The existence of a good, year-round water source at the surface in the discontinuous
zone indicates that the ground is not frozen beneath the well. Year-round springs, large streams, and lakes serve as water sources. Even if the water is nonpotable, these sources indicate windows in the permafrost where dug, driven, jetted, or drilled wells may be located.
  Vegetation may indicate the presence and thickness of permafrost. Although tree roots rarely exceed a
depth of 3-ft, the presence of large trees indicates that only the top of the permafrost during the thawing season is deeper than usual. Large trees along a river suggest that either the top of the permafrost is
depressed to afford a limited supply of water or that permafrost may be absent. The presence of pine or aspen indicates a similar depression of the permafrost table or possibly the complete absence of
permafrost. The presence of willow shrubs (not trees), peat and moss, or stunted tamarack and birches
indicates a thin zone of summer thawing (active zone) and the presence of cold, thick permafrost near the surface. These indicators are more frequent in a thick, continuous permafrost zone.
3. *Thick, Continuous Permafrost*. Generally, surface sources are required when underlain by thick,
continuous permafrost. Available groundwater requires drilling deep (several hundred ft) wells through the permafrost. Such a task may be beyond the scope of military OPS.

## 9.2 Well Drilling

The list below describes well drilling considerations in cold weather:

1. *Drilling Equipment*. The same drilling equipment for normal well drilling is required, but additional
accessories are necessary because of adverse weather conditions. Portable gasoline or diesel heaters are a
must for personnel and equipment at the construction site. Electrical or oil immersion heaters may also be necessary for storage and settling reservoirs. Lastly, tents or sheds are required to protect personnel from cold winds or storms.
2. *Rotary Drilling*. In permafrost regions, use the rotary-drilling method for deep drilling and large diameter
holes and for shallow drilling and small holes. The procedure for rotary drilling in frigid climates is the same as in temperate climates except for temperature requirements of the drilling fluid. In adverse weather conditions (extremely low temperatures and snowstorms), construct shelters to protect the rigs and to
maintain comfortable working temperatures.
  At temperatures below -20 F, generally no drilling is done. The mud used in rotary drilling should be at
near-freezing temperatures when entering the drill stem to prevent thawing and caving of the hole. When necessary, apply enough heat to the mud to prevent the hole from freezing. This may be accomplished at the mud pump with a low heat propane torch or electric heater. Make sure the rig operates continuously to prevent the mud pump and accessories, bits, and casing from freezing during OPS. If OPS must stop at
night, remove the tools, let ice form over the well, and drill out the ice in the morning. In a finished well, use the rotary rig to circulate the water to prevent freezing until the pump is installed.
3. *Jet-Drive Drilling*. This is another method of constructing small wells in cold climates, in addition to
either a warm or discontinuous permafrost condition. The wells are usually 2 inches in diameter and are
drilled to a depth of 200 ft.
  The equipment is simple, light, and consists of a small derrick and a small engine with a cathead. The pipe
is pushed into the ground and advanced manually, dropping a small weight fastened to a line running over a sheave on the derrick to the cathead. The jet point is made from a reducer, which is ground into a bullet
shape and attached to the end of the 2-inch pipe. Drill several l/4-inch holes above the jet point a distance of 1 to 2 ft. A thaw-line pipe projects a maximum of 2 ft through the head of the drive point.

  Pump a water jet through the thaw-line pipe during drilling OPS. Suspend the pipe on a simple chain hoist
and slowly move the pipe up and down. The thaw-line pipe penetrates the sediments ahead of the jet point. When the thaw-line pipe is about 2 ft ahead of the jet point, retract the pipe. The casing is driven as far as possible; repeat the process. Use water no warmer than 40 F in this process. Jet-drive drilling proceeds
about three times as fast in permafrost as in thawed ground. Figure 9-2 illustrates a percussion-type drilling rig used in cold weather well drilling, and Figure 9-3 shows a jet-drive point used with the rig.
  For depths of 100 ft or less, one man operating a rig jet drives about 28 ft per day in frozen ground. If the
ground is thawing, the footage per day is reduced. A 2-inch well equipped with a suction pump with less than 20-ft drawdown yields up to 40 gallons of water per minute. At a depth of more than 100 ft, jet-drive drilling becomes rather slow and difficult. Therefore, limit jet-drive drilling to the southern portions of the permafrost zone where possible.
4. *Drilling Fluids*. The fluid used in drilling through permafrost must remain in a liquid state (do not heat)
during drilling OPS and must not contaminate possible water sources; although contamination is
eliminated by pumping. When using mud, try to keep it from freezing by adding chemical agents such as aquagel, gel-flake, barite, fibratex, smentex, micatex, and impermex. An increase in the viscosity of the
drilling mud results in a decrease in mud flow, eventually causing freezing or sticking of the bit. Be careful during periods of excessive permafrost thawing as the hole could slough during drilling.
  Brine, as a drilling fluid, is not ideal in permafrost areas because it promotes contamination and excessive
thawing; requiring clean drilling equipment at all times once used. It could corrode the drill string, rig, and pump and cause a skin rash on personnel. Use brine sparingly, but only when required. The well is developed by pumping after drilling, which clears the well of brine. A suitable brine solution is 35 lb of
rock salt mixed with 53 gallons of water. In the cold weather, 100 lb of rock salt is ample for drilling a 15-
to 20-ft hole. Figure 9-4 shows the specific gravity of drilling fluids when using salt additives in muddrilling OPS.

Adding salts to drilling fluids reduces the viscosity.

5. *Air Rotary Drilling*. This is the preferred drilling method for intermediate- or large-depth wells if the
appropriate equipment is available since the precautions for rotary drilling are not necessary.
6. *Well Installation and Completion*. Some of the same installation and development methods used in warm
climates are also applicable in cold climates, with some precautions. Try to minimize prolonged contact of
surface water with any permafrost. Doing so avoids freezing in the hole or thawing and sloughing the
previously frozen wall; which may require the need to redrill. The single-string method is appropriate to install the screen and casing together for wells in rock-like permafrost because disturbance is minimal.
  The potential for water freezing after the well starts routine production requires continuous review.
Insulating the well by centering a regular well casing in an oversized drill hole and by packing the annulus
with dry sand through the permafrost interval may suffice; accommodating continuous rather than
intermittent pumping.
INTENTIONALLY BLANK

## Appendix A Army Water Supply And Well Drilling A.1 Concept

In the Army, supply of water (potable and nonpotable) in theaters of operations is the mission of Army logisticians supported by Army engineer (GE/construction) efforts. Water detection and well drilling are specialized mission sets of Army engineers.

## A.2 Organization And Scope

1. *Capabilities*. Army well drilling teams are required to develop and provide adequate water resources for
deployed forces and have the capabilities as described in Paragraph 1.4.
2. *Requirements*. The hazards and risks associated with water-well drilling require the highest standards of
training, proficiency, and safety. The required documents listed under Army Publications in References imply specific responsibilities that apply to Army water-well teams and OPS. Accordingly, each team shall maintain, at a minimum, copies of the applicable documents and publications.
3. *Team Composition*. Army well drilling teams are typically a theater engineer command asset and should
be deployed and employed by an engineer battalion (or company) capable of providing engineer expertise
and needed logistical support. Since the team has limited personnel, the engineer headquarters must also plan for security at any work site. The Army well drilling team is inherently modular and deploys to the OA with the organic equipment they use to drill and complete a well. Although teams may require augmentation for force protection or other concerns, they are usually broken down into five special
positions and duties, which are described in Paragraph 3.1. (See Figure A-1 for the Army modular well drilling headquarters, and Figure A-2 for the Army well drilling team capabilities.)


## A.3 Equipment

Army drilling rigs are truck mounted. Current Army well drilling and well-completion equipment consists of:

1. A truck-mounted drilling machine mounted on a NavistarTM 6-by-6 truck chassis.
2. A truck-mounted tender vehicle. 3. A lightweight well-completion kit (including accessories, supplies, and tools needed for drilling a well).
Consumable products used in completing the well are not organic to the organization.

The 600-ft Army WDS (see Figure A-3) is deployed with minimal preparation and support equipment anywhere in the world. With the completion kit, drillers are able to complete a well to a depth of 600 ft using mud, air, or a down-hole hammer with or without foam injection. With augmentation of an auxiliary 250 cfm air compressor, drill pipe, and 900 ft of drilling stem, the 600-ft WDS drills up to depths of 1,500 ft with additional air compressor set up in a variety of soil conditions using mud or drilling foam. Additional equipment includes casing elevators and slips, larger drill bits, and an additional drill stem. Well drilling teams should ensure that they have the rig accessory kit for the LP-12 to be fully mission capable. The 600-ft WDS is:

1. Air transportable by C-130 and C-5. The vehicle is equipped for tie-down as well as lift operations during
transport.
2. Equipped for air-percussion drilling and for rotary drilling with mud or air. 3. Equipped to drill wells up to 600 ft. 4. Adaptable for drilling to depth of 1,500 ft. 5. Truck mounted for mobility.
6. A three-mode, water-transfer pumping system.
The 600 ft WDS replaced the CF-15-S model trailer-mounted 1,500 ft well drilling machine and 1,500 ft completion kit.

## A.4 Field Water Supply

Tactical and logistical planners determine and coordinate water support functions in the OA for the Army. Water distribution units are responsible for distribution. Preventive medicine personnel analyze, test, and certify water supplies. Together, they ensure that there is enough quality water production and distribution to continuously support the forces. Army logistics planners, using FM 10-52, *Water Supplies in Theaters of Operations*, estimate the required quantity and quality based on the mission, size of the supported force, dispersion of forces in the AO, and availability of various sources of water supply.

Army logisticians use FM 10-52-1, *Water Supply Point Equipment and Operations*, to plan the actual distribution of water to units. Logistics units, typically supply companies, normally have a water distribution platoon assigned to conduct water supply operations, including establishing and operating a water supply point. To do this effectively, Army logistics units may require Army engineering support to include things such as:

1. Building combat roads and trails to establish traffic control patterns at the distribution site.
2. Constructing improvised dams for impounding small streams to obtain a steady source of water. 3. Constructing gravel pads to ensure a steady platform for operating ROWPUs. 4. Constructing a brine pit (ROWPU support). 5. Digging intake galleries along banks of streams.
6. Improving drainage at the facility to prevent muddy conditions that may cause the area to become
unusable.
7. Constructing pads for water storage blivits. 8. Constructing or repairing troop bed down, protection and AT, and maintenance facilities (because water
distribution points are often long-term operations).
9. Providing diving support for the emplacement of offshore water hoses and pipelines.
10. Rehabilitating damaged wells and distribution points.
Most water supply units are equipped with two 10-mile segments of the tactical water distribution system. The tactical water distribution system is used to transport potable water from wells, desalination plants, and other sources over distances less than 10 miles (per segment) to 20,000-gallon fabric storage tanks. The system is capable of transporting water forward up to 80 miles at a rate of 600 gpm across level terrain. Engineers' support this system by providing GE support to set up the distribution point, leveling water storage pads, and assisting with the emplacement of the hose system. The need to cross hard-surfaced roads and other obstacles requires engineers to install culverts or emplace suspension kits at various locations throughout the hose system.

## A.5 Reachback Resources

The use of reachback or field force engineering (FFE) refers to linking well-trained and well-equipped military and civilian deployed forces with state side teams for their technical expertise. The objective is to effectively execute USACE roles, such as engineering expertise, contract construction, real estate acquisition and disposal, environmental engineering, and water detection, in the OA, and to maximize support to the joint force commander (JFC). These teams provide rapid, actionable engineering analyses across the range of military operations in support of US forces and the nation. Reachback provides support for technical engineering analyses, geographic information systems, intelligence support, training, and equipment. Accessing reachback support is simple and only requires deployed personnel from any military Service or other US government organization (e.g., the Department of State (DOS) and the Federal Emergency Management Agency (FEMA)) to submit a request for information (RFI) via unclassified or classified websites, e-mail, video teleconference, or by telephone to the Engineering Infrastructure and Intelligence Reachback Center (EI2RC) in Mobile, Alabama, or the TeleEngineering Operations Center (TEOC) in Vicksburg, Mississippi (see Figure A-4). Once a request is submitted, it is routed to trained response teams, centers of expertise, or laboratories for solutions. The personnel working the RFI provide the response to the requestor to solve the problem and the data is archived in a repository. Additionally, there is extensive capability for attaining hydrology and geology information from the USACE Engineer Research and Development Center (ERDC). ERDC has a vast amount of prerecorded data on places around the world where previous wells were drilled successfully. This information is not classified and is easily attained at http://www.sam.usace.army.mil/en/en.htm. Once on the site, simply click on the Water Resource Assessments link on the bottom right hand side of the page. Another method for obtaining necessary data is through exercising the established reachback processes.



Website
E-mail
Mail
Phone
COMM
CESAM-EN (EI2RC)
CEEI2RC
https://ei2rc.usace.army.mil
251-690-2039
109 Saint Joseph Street
TEOC
https://teleengineering.usace.army.mil
COMM
Mobile, AL 36602
TEOC-VTC

601-634-2735


DSN
CEERDC, TEOC


312-446-2735
RM 42, BLDG 3294


VTC
3909 Halls Ferry Rd


601-634-3485
Vicksburg, MS 39180-6199

## Unclassified

COMM
Director
HYDRO
http://tec.army.mil
703-428-7869
Topographic Engineering

DSN
Center

312-364-7869
Attn: CEERD-TO-H

7701 Telegraph Rd
Use '@usace.army.mil' at the end of each email.
Alexandria, VA 22315
OrgMBoxCEEI2RC@usace
http://ei2rc.usace.army.smil.mil
601-634-4231 (STU-III)

TEOC@TeleEngineering
http://www.teleengineering.army.smil.mil


NA

HYDRO@TEC

## Classified



Use '.army.smil.mil' at the

## Appendix B Navy Well Drilling B.1 Concept

Naval mobile construction battalions (NMCBs), also known as Seabees, under the FIRST Naval Construction Division (NCD) and Navy Expeditionary Combat Command (NECC) respectively are tasked as part of their primary mission to provide water-well drilling support for the Navy and Marine Corps, other Services, and joint task forces as tasked by the unified combatant commanders (CCDRs) through the Navy component commander or an assigned joint force land/maritime component commander. To accomplish well drilling missions, tasktailored well drilling teams deploy from an NMCB by land, air, or sea.
Refer to Navy warfare publication (NWP) 4-04, *Naval Civil Engineering Operations* and Navy tactics, techniques, and procedures ((Navy tactics, techniques, and procedures (NTTP) 4-04.1M/Marine Corps warfighting publication (MCWP)) 4-11.5, *Seabee Operations in the MAGTF* for doctrinal evidence and additional information on naval construction force (NCF) capabilities.

## B.2 Organization And Scope

The list below describes the Navy's well drilling organization and scope:

1. *Capabilities*. Navy well drilling teams are required to develop and provide adequate water resources for
deployed forces and have the capabilities as described in Paragraph 1.4.
2. *Requirements*. The hazards and risks associated with water-well drilling require the highest standards of
training, proficiency, and safety. The required documents listed under Navy Publications in References imply specific responsibilities that apply to Navy water-well teams and OPS. Accordingly, each team shall
maintain, at a minimum, copies of the applicable documents and publications
3. *Team Composition*. A water-well drilling team is composed of a minimum number of personnel to
accomplish the tasked mission. Each NMCB table of allowance (TOA) includes four water-well drilling
technicians (Navy enlisted classification (NEC) 5707) and the necessary well-drilling equipment and
materials to develop water wells from deep subsurface aquifers. A well drilling team is composed of
qualified individuals of any Seabee rating (e.g, utilitiesman, equipment operator, construction mechanic, etc.) in grades E1 through E9; with the four NEC designated personnel forming the nucleus of the team. A chief or senior chief (E8 or E9) is usually responsible for the overall well drilling team and OPS. Although teams may require augmentation for force protection or other concerns, they are usually broken down into
five special positions and duties, which are described in Paragraph 3.1.

## B.3 Equipment

The list below describes the Navy's well drilling equipment:

1. *The T2W*.  The Atlas Corporation T2W model water-well drilling machine (see Figure B-1) is an allwheel-drive, self-propelled rig. The T2W is shippable on a C-17 or larger aircraft without disassembly. The machine is an all-hydraulic, top-head drive unit with a stationary mast capable of employing standard 20-foot drill steel. The T2W has a top speed of 65 miles per hour (mph) and is designed for over-the-road mobility. It is heavy duty, highly mobile, and suitable for rapid deployment with expeditionary engineer units. Figure B-2 illustrates specifications for the T2W.
  The T2W is capable of mud and air rotary drilling, rotary percussion, or down-hole hammer drilling, using
an auxiliary air compressor. A mud pump, water-injection pump, in-line oiler, four comer-mounted
leveling jacks, fore and aft pintle hooks, utility hoist, driller's station, and driver's station are part of the
T2W. The T2W is deployed with a kit that includes lightweight drill steel, drill collars, tricone bits, downhole air hammer, and miscellaneous subs and adaptors for drilling to a depth of up to1,500 -ft. Because of the various drilling capabilities, the T2W drills in any geological formation. If drilling requires the air compressor, it is brought to the site with the drill rig or delivered by a separate support vehicle. For muddrilling OPS, teams need a water truck and the equipment to dig the mud pits. Refer to NWP 4-04, Naval
Civil Engineering Operations, for a comprehensive list of NCF capabilities and equipment.
2. *Air Compressor*. One wheel-mounted, diesel-engine-driven, 750-cfm, 300-psig air compressor is included
in each NMCB TOA for performing down-hole hammer drilling techniques. The WDS tender truck is capable of towing this air compressor. The T2W does not have an on-board air compressor.
3. *Well-Completion Kit*. Each NMCB water-well drilling team is responsible for coordinating or obtaining
well-completion materials necessary to develop and complete assigned well/(s) in advance of the team's
arrival on site. Procurement of materials for tasked projects is coordinated with the supported unit's logistics officer and funding is always the responsibility of the supported unit. The supported unit's
logistics officer is also responsible for the resupply of necessary supplies.

## Specifications Overall Dimensions

Weight: 58,000 lb GVWR
Manufacturer: Atlas Copco
Length: 531-inches
Type: T2W
Width: 102-inches
Height (Mast Up): 495 inches
Shipping Dimensions: 3,913.1 cubic feet
Height (Mast Down): 148 inches
Engine Type: Caterpillar C-13, I-6 diesel
Fuel Capacity: 100 gallon Hydraulic Reservior: 100 gallon
Mud Pan capacity: 350 gallons
Engine Horsepower: 385 @2,100 rpm Trans: Fuller FRO-15219C, 10 spd manual
                             Medium: 0-110 rpm 8,000 ft/lb Top Head Rotation: Low: 0-80 rpm 12,000 ft/lb High: 0-275 rpm 3,500 ft/lb Drum Capacity:       Main: 12,000 lb  (jib out, 1,500 lb)
Drilling Capacity: 24 inch, 1,500 feet
Derrick Capacity:    Pulldown: 30,000 lb Auxiliary: 4,000 lb
     Mud Rotary: 12.25-inch hole to 1,500 feet
                             Sand line: 4,000 lb
     Downhole Hammer: 8-inch to 1,500 feet
              (with sufficient air supply)
                             Hold back: 30,000 lb
Grout Pump Capacity: 30 gpm
Self Recovery Winch: 25,000 lb pull
Mud Pump Capacity: 300 gpm Water Injection Pump Capacity: 25 gpm
(single 3/4 in line)

INTENTIONALLY BALNK

## Appendix C Air Force Well Drilling C.1 Concept

Air Force well drilling teams are organized and assigned according to Air Force Instruction (AFI) 10-209, RED
HORSE Program. AFI 10-209 outlines the organizational concepts and capabilities of the Rapid Engineer Deployable Heavy Operational Repair Squadron Engineers (RED HORSE). This squadron provides the Air Force with a highly mobile, self-sufficient, rapidly deployable, civil engineer, heavy construction and repair capability.

The Air Force headquarters control RED HORSE. Well drilling units are assigned as a special-skills team to an operational RED HORSE unit. The RED HORSE unit provides the logistical support necessary to complete the well drilling mission and the administrative support well drilling teams require.

## C.2 Organization And Scope

The list below describes the Air Force well drilling organization and scope:

1. *Capabilities*. Air Force well drilling teams are required to develop and provide adequate water resources
for deployed forces and have the capabilities as described in Paragraph 1.4.
2. *Requirements*. The hazards and risks associated with water-well drilling require the highest standards of
training, proficiency, and safety. The required documents listed under Air Force Publications in References imply specific responsibilities that apply to Air Force water-well teams and OPS. Accordingly,
each team shall maintain, at a minimum, copies of the applicable documents and publications.
3. *Team Composition*. A water-well drilling team is composed of a minimum of eight trained personnel (Unit
Task Code (UTC) 4FPRU, Small Horizontal Construction Team), equipment (UTC 4F9HK, Water-Well
Drilling Rig) and tools (UTC 4F9RU, Small Horizontal Construction Team Equipment). If 24-hour OPS
are required, then additional UTCs are needed (eight-person team = one shift). Teams are composed of seven Air Force Specialty Code (AFSC) 3E2X1 (construction equipment) personnel in grades E3 through
E8 and one (AFSC) 2T3XX (vehicle maintenance) person in grades E4 through E6.
  The noncommissioned OIC of the team has the responsibility for well drilling and OPS. The eight-man
team is usually broken down into five special positions and duties, which are described in Paragraph 3.1. The sixth member of the Air Force team provides vehicle maintenance while the seventh and eighth members are construction equipment personnel utilized for operational team safety, routine maintenance for the entire drilling set, and mud/foam utilization as needed. The final three members of the Air Force team are trained to fill in for any of the core drilling duties.

## C.3 Equipment

The equipment in the RED HORSE units is not standardized and varies in make and model. Contact the RED HORSE unit directly to obtain information on water drilling equipment. The Air Force is in the process of standardizing its well drilling equipment by procuring the GEFCO 50K Trailer- Mounted, Topdrive, Multipurpose Drill Rig. It is a top-drive, trailer-mounted, water-well drilling system consisting of a well drilling trailer, mud cleaning system, and trailer mounted compressor. Check with the program contacts for current status (see Figure C-1).

Mail
Phone

HQ Air Combat Command (ACC)

COMM

129 Andrews Street Suite 115B

757-764-2869

Langley AFB VA 23655-2769

DSN



312-574-2869

RED HORSE PM

COMM

HQ Air Force Civil Engineer Support Agency

850-283-6127

139 Barnes Drive Suite 1

DSN

Tyndall AFB FL 32403

312-523-6127


The list below describes the GEFCO 50K well drilling equipment:

1. *Drill Mission*. 1500-ft total depth (TD) capability utilizing 4 1/2-inch OD external flush drill pipe with 3
1/2-inch connections. Borehole max diameter for TD is 12 1/4 inches. Mud rotary capability is to TD. Air rotary capability is to TD. Hydraulic power is via quick coupler for 7.5 x 10 hydraulic powered mud pump and hydraulic powered mud recycling unit with flow controls at the operator's station. Air rotary capability is to TD via a skid mounted standard 1350/350 air compressor. Capable of deploying inside a
C-17/C-5 aircraft without removal of major drilling components (i.e., mast, mud pump, compressor, tophead drive).
  Mud cleaning system processes 450 gpm of fluid and is self contained and powered by its own power
supply. Mud pump is stand-alone unit of the Tri-Plex Centerline hydraulic variety powered by engine off mud recycling system. System is skid mounted (of oilfield design) and transportable on flat-bed tilt trailer
with winch-on capability. Mud system is in two 20-ft sections to meet transport requirements (i.e., generator or hydraulic power, pumping system on one, fluid system on the other)
2. *Tophead Drive*. Vertical rail guided design, retractable back into the mast off centerline of the hole
allowing wire-line access for casing and tool handling access to the borehole. Hydrostatically powered
tophead rotary with an infinitely controlled rotation speed of 0 to 120 rpm and a maximum torque of 70,000 inch-lb. The stroke of the pull down and holdback cylinder allows the head to travel 29 ft up and down the mast. Measures are in-place to identify high torque mode and low torque mode to prevent damaging drill pipe. Shifting modes is accomplished via a two-speed head and/or with a 4-speed air shift
transmission to meet multiple variable speed ranges. A quick disconnect adapter to accommodate a variety
of tool connections is supplied with the machine.
3. *Mast.* Lattice design with a minimum rated working capacity of 50,000 lbs and a minimum working height
of 30-ft under the jib boom to top of table. The sliding table retracts hydraulically to allow the setting of 16-inch OD casing minimum (minimum 18-inch table opening). Tables are equipped with a hinged section to allow easy access to the borehole: 4 1/2, 5 3/4, 6, 8, 9 7/8, and 12 3/8 inches.
4. *Air Compressor*. A Sullair single-stage rotary screw compressor rated minimum 300 cfm and 250 psi.
Hydraulically driven and equipped with necessary valves, pressure gauges, and receiver tank.
5. *Main Hoist*. 50,000 lb hoist capacity via two part line configuration hoisted by a hydraulic winch with
heavy-duty crown sheaves. Winch has a line speed of 80 fpm forward and reverse direction. Equipped with 150 ft of 3/4-inch nonrotating wire rope with safety swivel hook and single sheave block for 2-part line (50,000 lb) capacity for TD tool and casing handling.
6. *Hydraulic Leveling Jacks*. Four (4) hydraulic leveling jacks, with two located up front behind truck cab
and two at rear of drill. Jacks are 4.5-inches column diameter with 36-inch stroke, the extension portion is equipped with a steel boot to resists side thrust and reduce wear on cylinder bore and cylinder rod. Jacks
have integrally locked check valves with thermal reliefs, 12-inch minimum swivel pads, and 1618-inch road clearance in the full up travel position with top of jacks extended above deck. Jack controls are located at the drillers' station. Jack pads may be removable for clearance.

7. *Single Pipe Loader*. Single pipe loader mounted on right side of mast consisting of a holding pod with
hand wheel on bottom and a guide with automatic latch on top. A hand wheel to rotate pipe to unscrew lift plug and the unit swings from side of mast to center of hole for automatic line up with top head.
8. *4 X 3 Mission Magnum*. A 4 x 3-inch Mission Magnum Sandmaster centrifugal pump with 13-inch
impeller, hydraulically driven, and infinite speed control. Pump capable of minimum 320 gpm and a minimum pressure of 230 psi.
9. *Water Injection*. CAT Model 2025 triplex pump with pulse foam pump. Hydraulically driven variable
speed pump at 18 gpm.
10. *Lubricator (Down-Hole-Hammer)*. Seven (7) gallon reservoir capacity lubricator. Electrically controlled
from operators' station, metering valve at drillers' station to control injection rate, and the discharged
plumbed to the mast stand-pipe.
11. *Remote Air Supply*. 100 psi from the compressor or truck engine air compressor system operates air
powered hand tools. Regulator, air pressure gauges are provided for both supply pressure and working
pressure.
12. *Drill Trailer Chassis*. 30-ft, 8-ft wide, 11-ft high mounted on a triple axle trailer. Low profile/super
single tires per wheel assembly (Goodyear G465A Radial Super Single load range L 385/65R22.5).
13. *Mud Recycling System and Mud Pump*. 500 gpm, consisting of a heavy duty oilfield type skid mounted
tank with one division. The tank hosts 3 centrifugal pumps, mud mixing hopper, 3 mud guns, 1 mud cleaner and dump gates. The tank includes mud slides for shakers, handrails, lights, grating, manholes for each pit and fold down walkways. Overall length of tank is 20 ft with a holding/working capacity of 3,000 gallons. Mud Pump is a Hydraulic Duplex design is capable of minimum 450 gpm at 255 psi.
14. *Air Compressor*. Skid-mounted (oilfield design) with 1350 cfm/350 psi diesel powered air compressor,
constructed in a weather/sound proof (low noise) enclosure, with a minimum 3-inch diameter discharge manifold with hammer unions, wipe-check safety cables, 2 each 30-ft x 3-inch high pressure air hose,
female connectors on each end, 2 each male by male spud connectors provided to connect hoses if needed.
Fuel tank has capacity to operate unit for 12 continuous hours at full capacity.
15. *Air Transportability*. The complete Water-Well Drilling System is air deployable by Air Force C-17/C-5
aircraft in a drive-on/drive-off mode. This Water-Well Drilling System (to include the Well Drill Truck, Mud Cleaning System, and all other components that make up this Well Drilling System) are loadable/unloadable without the use of approach shoring or material handling equipment (e.g., forklifts, aircraft loaders, etc.). Possibly more than one C-17 aircraft may be required to accommodate this well drilling system. Major components, such as the mud pump, hoist assembly, mast, etc., are not removed
either whole or partially from the vehicles to meet dimensional or weight requirements for aircraft driveon loading. Removal or replacement of any other parts require no longer than 2 hours for a properly trained mechanic with common hand tools or special tools provided
INTENTIONALLY BLANK

## Appendix D Water Resource Detection Team D.1 Concept

Detection of groundwater sources is critical for successful well drilling OPS. Without proper analysis, the potential for finding an adequate source is less likely. In unfamiliar terrain, drilling by trial-and-error (i.e., exploratory drilling or test holes) is costly and time-consuming. It is only recommended if other water detection methods are not available or are proven to be unsuccessful. Determining the most suitable sites to drill for groundwater falls primarily on geospatial teams and the WDRT.
Geospatial teams use data from terrain and other geospatial products to recommend the best sites to conduct well drilling OPS. These teams use the results of field reconnaissance and geophysical surveys to provide recommendations. Geospatial teams are not equipped or trained for actual detection, only predictive analysis. They also have the capability of reachback to experts at the TEC to obtain data and analysis from historic records and additional subject matter experts that are able to identify areas with a high potential for developing water supply sources. Contact TEC at https://tsunami.tec.army.mil/Products/WaterResources/. The mission of the WDRT is to assist military planners, terrain teams, and all military Service well-drilling teams in locating adequate groundwater supplies before drilling to improve military well-drilling success. Through expertise and studies they identify high-potential areas for the best possible quality of water within available drilling equipment capability; in order to meet the water production requirements of the mission. The following four areas or elements are capabilities that the WRDT provides:

1. Database. The TEC produces and maintains a worldwide DOD Water Resources Database of available
water supply and hydrologic data, including groundwater resources. The WRDB is derived from classified and open-source data, maps, documents, and imagery. When specific missions and requests are received
for areas where data is uncertain or inconclusive, the team researches additional sources and data unique to the area. The resulting WRDT product or report summarizes the information critical to planning a successful well, such as the hydrogeology, target depth, aquifer material, expected yield, and probable
water quality. Office studies, based on research and analysis of existing data, are the most cost effective
and timely WRDT approach and takes hours to days to complete.
2. Remote sensing. If databases and other supplemental information are inadequate, aerial or satellite
imagery is studied and analyzed for indications of groundwater. This source is especially useful in a
hardrock area, where siting wells on significant fractures and fracture intersections is the key to success.
The acquisition and analysis of imagery increases the time and cost to complete an office study.
3. Supporting specialists. If office studies including imagery analysis are inadequate, one or more supporting
specialists may be deployed to the site. These specialists contact HN groundwater experts, collect and evaluate in-country data associated with existing or historic wells, and conduct hydrogeologic field reconnaissance of specific areas before drilling. They may also assist with interpreting well cuttings and
down-hole electric logging during drilling. Field studies take days to weeks to complete.
4. Geophysics. Should information gathered by supporting specialists be insufficient, additional local site
investigations may be necessary using exploratory geophysics. Geophysicists may deploy to the site to conduct electrical resistivity, seismic refraction, or other on-site tests to better define the subsurface
before drilling. Geophysical exploration and data analysis generally takes weeks to complete. Costs are
significantly higher than for office-based studies and are paid by the requester.
WDRT requests may be made directed to TEC by any involved stakeholder/Service and need not be approved through a chain of command. WDRT requests are examined and high-potential areas are identified through the examination of existing databases, followed by the collection and analysis of additional sources and imagery. In those rare cases when high-potential water sites cannot be identified from source data and imagery, teams from the supporting specialists and/or geophysics elements are able to deploy for on-site investigation by request. This should take place before the arrival of Service well-drillers. If deployed to an OA, the WRDT operates as a component of the theater engineer command or senior engineer organization in theater. As with any USACE
capabilities, activation of the WRDT for deployment is not automatic; it must be requested through the supporting theater engineer command or through other appropriate command channels to TEC. The supported commander provides and arranges for the WRDT's logistics and administrative support necessary for mission accomplishment.

The Army TEC provides short-course training on groundwater and hydrogeologic concepts by request to all branches of Service. Traditionally this training is provided to well drilling units prior to their deployment and training is custom-tailored to the conditions that are to be encountered in the deployment area. Focus areas include: general hydrogeology and groundwater concepts, hydrogeology and expected conditions in the deployment AO, challenges to well drilling in the AO, and reachback assistance. Please contact TEC's Hydrologic Analysis Team for further information. POC information is available at TEC's website: https://tsunami.tec.army.mil/Products/WaterResources.

## Appendix E Forms E.1 Well Drilling Forms

The list below describes the well drilling forms applicable to all Services:

1. *DD Form 2678*. Well Driller's Log (see Figure E-1).
2. *DD Form 2679*. Piping and Casing Log (see Figure E-2).
3. *DD Form 2680*. Military Water-Well-Completion Summary Report (see Figure E-3).

INTENTIONALLY BLANK

## References

The following sources are cited or paraphrased in NTRP 4.04.2.13/FM 3-34.469/AFMAN 32-1072 (DECEMBER 2008).

## Army Publications

1. FM 3-34.610 (5-33), Terrain Analysis. 2. FM 3-34.310 (5-34), Engineer Field Data.
3. FM 3-34.23 (5-116), Engineer Operations: Echelons above Corps.
4. FM 3-34.494 (5-125), Rigging Techniques. 5. FM 4-20.21 (10-52), Water Supply in Theaters of Operations. 6. 10-52-1, Water Supply Point Equipment and Operations.

## Multiservice Publications

7. FM 21-10/MCRP 4-11.1D, Field Hygiene and Sanitation. 8. NTTP 4-04.1/MCWP 4-11.5, Seabee Operations in the MAGTF

## Navy And Marine Corps Publications

9. MCWP 4-11.6, Petroleum and Water Logistics Operations.
10. NWP 4-04, Naval Civil Engineering Operations

## Nonmilitary Publications

11. Baroid Properties and Performance of Drilling Muds (Catalog no. WW 1000-01) (Houston, Texas: Baroid
Drilling Fluids, 1989).
12. Geology and Geophysics for Military Well Drillers. (Vicksburg, Mississippi: Geotechnical Laboratory,
US Army Engineers Waterways Experiment Station, n.d).
13. Gibson, U. P. and Rexford D. Singer, Water Well Manual: A Practical Guide for Locating and
Constructing Wells for Individual and Small Community Water Supplies (Berkeley, California: Premier Press, 1971).
14. Keys, W. Scott, and L. M. MacCary, Application of Borehole Geophysics to Water-Resources
Investigations, Techniques of Water-Resources Investigations (TWRI), Bo2 (Washington, DC:
Government Printing Office, 1971).
15. Percussion Drilling Equipment Operation and Maintenance Manual. (Catalog no. M525) (Houston,
Texas: Sandvik Rock Tools, Inc., n.d.).
16. The Button Bit vs. The Rock (Publication Form no. 7698-l) (Roanoke, Virginia: Ingersoll-Rand Company,
n.d.).
17. United States Geological Survey (USGS), Ground Water Atlas of the United States (Reston, Virginia:
United States Geological Survey, 2000).
    Hydrologic Atlas (HA)
  HA 730-A, Introduction and National Summary
HA 730-B, California, Nevada HA 730-C, Arizona, Colorado, New Mexico, Utah HA 730-D, Kansas, Missouri, Nebraska HA 730-E, Oklahoma, Texas HA 730-F, Arkansas, Louisiana, Mississippi HA 730-G, Alabama, Florida, Georgia, South Carolina
HA 730-H, Idaho, Oregon, Washington
HA 730-I, Montana, North Dakota, South Dakota, Wyoming HA 730-J, Iowa, Michigan, Minnesota, Wisconsin HA 730-K, Illinois, Indiana, Kentucky, Ohio, Tennessee HA 730-L, Delaware, Maryland, New Jersey, North Carolina, Pennsylvania, Virginia, West Virginia HA 730-M, Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode Island, Vermont HA 730-N, Alaska, Hawaii, Puerto Rico, and the US Virgin Islands

## Standardization Agreements (Stanags)

18. STANAG 2885 ENGR (Edition 4), Emergency Supply of Water in War.

## Required Publications

Required publications are sources that users must read in order to understand or comply with this publication.

## Air Force Publications

19. AFI 10-209 (AFR 93-9), RED HORSE Program.
20. AFI 91-202, The US Air Force Mishap Prevention Program.
21. AFI 91-301, Air Force Occupational and Environmental Safety, Fire Protection, and Health (AFOSH)
Program.
22. Applicable OPS, maintenance, repair, and repair parts manuals for the assigned well-drilling rig.
23. TO 1C-130A-9, Cargo Loading Manual, 16 June 1980.

## Army Publications

24. FM 3-34.214 (5-250), Explosives and Demolitions.
25. FM 3-34.450 (5-410), Military Soils Engineering. 26. FM 3-34.452 (TM 5-545), Geology.
27. STP 5-62J12-SM-TG, Soldier's Manual and Trainer's Guide, MOS 62J, General Construction Equipment
Operator, Skill Levels 1/2.
28. STP 5-62N34-SM-TG, Soldier's Manual and Trainer's Guide, MOS 62N, Construction Equipment
Supervisor, Skill Levels 3/4.

## Department Of Defense (Dod) Forms And Publications

29. DD Form 2678, Well Driller's Log. 30. DD Form 2679, Piping and Casing Log. 31. DD Form 2680, Military Water-Well-Completion Summary Report. 32. Defense Mapping Agency (DMA), Catalog of Maps, Charts, and Related Products, Part 3, Topographic
Products (Maryland: Defense Mapping Agency Office of Distribution Services (DMAODS), n.d.).

## Multiservice Publications

33. TM 5-818-5/NAVFAC P-418/AFM 88-5, Dewatering and Groundwater Control.

## Navy Publications

34. Applicable NMCB operations orders. 35. Applicable repair parts manual. 36. Atlas Copco T2W/International Standards Organization air-transportable water drill (ITWD) operations
manuals.
37. NEC 5707 Water Well Drillers course data and CD.
38. Water Well Special Construction Battalion Training (SCBT) course data.

## Nonmilitary Publications

39. American Water Works Association (AWWA) A100-66, Standard for Deep Wells, 1966. 40. , A100-6, Standard for Water Wells, 2006. 41. Division of Safety, Engineering and Research Center, Driller's Safety Manual (Colorado: United States
(US) Bureau of Reclamation, 1990).
42. NL Industries, Baroid Drilling Mud Data Bo(Houston, Texas: Baroid Division, NL Industries, 1954).

## Recommended Readings Army Publications

43. AR 614-200, Enlisted Assignments and Utilization Management. 44. AR 735-5, Policies and Procedures for Property Accountability. 45. AR 750-1, Army Materiel Maintenance Policy. 46. FM 3-34, Engineer Operations. 47. FM 3-34.400 (5-104), General Engineering. 48. FM 3-34.405 (5-412), Project Management. 49. FM 3-34.420 (5-434), Earthmoving Operations. 50. FM 3-34.433 (5-233), Construction Surveying. 51. FM 6-22 (22-100), Army Leadership. 52. FM 7-1 (25-101), Battle Focused Training. 53. TM 5-3820-256-10, Operator's Manual for Drilling System, Well, Rotary, Truck Mounted, Air
Transportable, 600 Feet Capacity, Model 165F299 (NSN 3820-01-246-4276).
54. TM 5-3820-256-24-1, Drilling Machine, Model LP-12 (NSN 3820-01-246-4276).
55. TM 5-3820-256-24-2, Support Vehicle, Model LP-12 (NSN 3820-01-246-4276). 56. TM 5-3820-256-24-3, Drilling System Trucks, Model LP-12 (NSN 3820-01-246-4276).
57. TM 5-3820-256-24-4, Drilling System Trucks, Model LP-12 (NSN 3820-01-246-4276). 58. TM 5-3820-256-24-5, Drilling System Trucks, Model LP-12 (NSN 3820-01-246-4276). 59. TM 5-3820-256-24-6, Well-Completion Kit, Model LP-12 (NSN 3820-01-246-4276). 60. TM 5-3820-256-24P-1, Drilling Machine, Model LP-12 (NSN 3820-01-246-4276).
61. TM 5-3820-256-24P-2, Drilling Machine Truck, Model LP-12 (NSN 3820-01-246-4276).
62. TM 5-3820-256-24P-3, Drilling Rig Tender, Model LP-12 (NSN 3820-01-246-4276).
63. TM 5-3820-256-24P-4, Drilling Rig Tender Truck, Model LP-12 (NSN 3820-01-246-4276).
64. US Army Engineer District, Mobile, Operational Guidelines for Humanitarian Civic Assistance Water-
Well Drilling, 2001.

## Multiservice Publications

65. FM 3-34.410 (5-430-00-l)/AFPAM 32-8013, Planning and Design of Roads, Airfields, and Heliports in
the Theater of Operations (Road Design), Volume I.
66. FM 3-34.411 (5-430-00-2)/AFJPAM 32-8013, Planning and Design of Roads, Airfields, and Heliports in
the Theater of Operations (Airfield Design), Volume II.

## Navy Publications

67. NTRP 4-04.2.1, Doctrinal Reference for the Naval Construction Force (Draft).

## Nonmilitary Publications

68. Australian Drilling Industry Training Committee Limited, Drilling: The Manual of Methods, Applications
and Management (Boca Raton, Florida: CRC Press, 1997).
69. National Ground Water Association (NGWA), Procedures for Well Drilling Operations (CD) (Ohio:
NGWA Press, 2006).
70. National Water Well Association, Well Drilling Manual (Ohio: National Water Well Association, 1970).
71. Smith, Stuart, ed., Manual of Water Well Construction Practices, Second Edition (Ohio: NGWA Press,
1998).
72. Sterrett, Robert J., ed., Groundwater and Wells, A Comprehensive Guide for the Design, Installation and
Maintenance of a Water Well, Third Edition (Minnesota: Smyth Companies, 2008).

## Informational Websites

73. Air Transport Community of Practice (CoP) website:  https://afkm.wpafb.af.mil/ASPs/CoP/EntryCoP.asp.
74. Atlas Copco.  http://atlascopco.com/us.
75. California Groundwater Association.  http://www.groundh2o.org/index.html.
76. Centers for Disease Control and Prevention.  http://www.cdc.gov/.
77. Franklin Pumps.  http://www.franklin-electric.com/Subm_text/sub.htm.
78. Grundfos Pumps Corporation.  http://www.grundfos.com/web/HOMEus.NSF.
79. National Groundwater Association.  http://www.ngwa.org/.
80. The Groundwater Foundation.  http://www.groundwater.org/.
81. Thompson Pumps.  http://www.thompsonpumps.com/product-lines.html.
82. United Nations, United Nations Educational, Scientific and Cultural Organization (UNESCO) Water
Portal.  http://www.un.org/issues/m-water.html.
83. , Water for Life.  http://www.un.org/waterforlifedecade.
84. United States (US) Department of the Interior, United States Geological Survey.  http://www.usgs.gov/.
85. United States (US) Environmental Protection Agency.  http://www.epa.gov/safewater/.
86. United States Army Corps of Engineers (USACE).  http://www.sam.usace.army.mil/.
87. Water Advocates.  http://www.wateradvocates.org/.
88. Water Pumping Systems.  http://www.deanbennett.com/aermotor-home.htm.
89. World Health Organization (WHO).  http://www.who.int/en/.

## Intentionally Blank Glossary

air-lift method. A pump-testing method that uses an air-lift pump. air rotary drilling. A well drilling method that uses compressed air as the circulating fluid. alluvium. Soils that are deposited by running water. annular. Shaped like or forming a ring.

## Ant-Mound-Like Openings. See Also **Qanat**

aquagel. Commercial chemical agent added to mud drilling fluid to prevent it from freezing. See also barite;
fibratex; **gel-flake; impermex; micatex**.
aquiclude. Subsurface rock or soil unit, such as clay, shale, and unfractured igneous and metamorphic rock that
do not transmit water readily and cannot be used as a water-supply source. Aquiclude is often used
interchangeably in well drilling literature with aquitard. See also **aquitard**.
aquifer. Saturated rock or soil unit, such as gravel, sand, sandstone, limestone, and fractured igneous and
metamorphic rock, that has sufficient hydraulic conductivity to supply water for a well or spring.
aquitard. A unit that retards or slows the passage of water. Aquitard is often used interchangeably in well
drilling literature with aquiclude. See also aquiclude.
attapulgite. Commercially processed clay used for drilling in brackish or salty water.
backwashing. Pumping water into the well under pressure, forcing it out of the screened section and up the
annulus.
bail. To make void or empty of contents. Also the mechanism that allows material in and out of the bottom of a
bailer.
bailer. A mechanical device used to remove material from a hole.
bail-down method. Installing screen using a special end fitting. bail-down placement. A method of simultaneously placing the gravel pack and installing the screen.

barafos. A white, granular sodium tripolyphosphate thinner and dispersant added to drilling fluid to prevent
mud from sticking to sand grains.
barite. Commercial chemical agent added to mud drilling fluid to prevent it from freezing. See also aquagel;
fibratex; gel-flake; impermex; micatex.
basalt. An igneous rock that is a very productive water bearer.
bentonite. Commercially processed clay used for drilling; bentonite forms naturally from decomposition of
volcanic ash, consists of aggregates of flat platelets, and contains sodium montmorillonite, which is important in building viscosity.
boundary indicators. Characteristics indicative of local or regional groundwater flow systems. casing ring and slip. A device used to suspend the casing at the ground surface and for pulling pipe from the
hole using jacks under each side of the casing ring.
catchment. Formation whine impervious rock underlies a zone of fractured rock or alluvium that serves as a
reservoir for infiltrated water; a catchment is a special type of aquifer.

## Cathodic Protection. See Also **Sacrificial Anode.**

centrifugal pump. A variable displacement pump in which water flows by the centrifugal force transmitted to
the pump in designed channels of a rotating impeller.
closed-well method. A compressed-air method that involves using compressed air to close the top of the well
with a cap. By arranging the equipment so air pressure builds up inside the casing water is forced out through the screen openings.
combat zone. That area required by combat forces for the conduct of operations. See also communications
zone. (JP 1-02. Source N/A.)
communications zone (COMMZ). Rear part of a theater of war or theater of operations (behind but
contiguous to the combat zone) which contains the lines of communications, establishments for supply and evacuation, and other agencies required for the immediate support and maintenance of the field forces. See
also **combat zone.** (JP 1-02. Source: JP 4-0)
compressed-air methods. A rapid and effective method of transferring water during well-development by
using the potential energy created by pressurized air. See also **closed-well method; open-well method.**
CON DET. A wetting agent added to drilling fluid to increase the dispersion action of polyphosphates.
confined aquifer. An aquifer that is completely filled with water and is overlaid by a confining bed. confining bed. Aquiclude that exists between aquifers. Water moves only within the aquifer. consolidated deposit. Rock that consists of mineral particles of different sizes and shapes. continuous permafrost. A zone where permafrost is thick with no unfrozen ground. See also
discontinuous permafrost; permafrost.
crop irrigation. Surface indicator that shows the use of surface water or groundwater for agriculture.
Darcy's Law. Principle that describes the flow of groundwater. discharge. Water that moves from one area into another.

discontinuous permafrost. A zone where permafrost is thin and maybe absent on the south slopes of hills, in
valley bottoms containing permeable alluvial material, and under surfaces that have been cleared of vegetation.
See also **continuous permafrost; permafrost**.
dispersion treatment. Adding dispersing agents to drilling fluid, backwashing, jetting water, or water
standing in the well to counteract the tendency of mud to stick to sand grains.
dissolution potential. The possibility of developing high secondary permeability in a soluble rock because the
rock dissolves through contact with groundwater.
dolomite. A carbonate rock that dissolves when carbon dioxide from the atmosphere and groundwater mix to
form carbonic acid.
double-casing placement. A method of placing gravel using a temporary outer casing. drainage basin. An area drained by a stream or river. See also hydrographic basin (local drainage
basin); major river basin; regional river basin.
drawdown. Measure of how much the water level near the well is lowered when the well is pumped.
draw works. Main drill-head hoists that are mechanically or hydraulically driven wire-line winches. driven method. Driven wells consist of a series of pipes with a point and a perforated pipe at the end in which
the point is forced into the ground.
drive point. Perforated pipe with a steel point at the lower end to break through pebbles or thin, hard layers. dump-bailer method. Placing grout in a casing using a dump-bailer machine. electric-line method. A procedure to measure the water level using a sounder. See also **sounder.** elevator (casing). A device used to handle pipe; the elevator is clamped around the pipe directly under the
coupling. See also **sand line**.
evaporite. Sedimentary rock that is generally capable of storing and transmitting groundwater but tends to
dissolve in the water

## E-Z Mud. A Synthetic, Inorganic Polymer. See Also Polymer; Poly-Sal; Revert.

fall-in. Material that accumulates in the bottom of the borehole after circulation stops.
feed drive. Mechanism on a rotary rig that applies a downward thrust to the drill string. fibratex. Commercial chemical agent added to mud drilling fluid to prevent it from freezing. See also aquagel;
barite; gel-flake; impermex; micatex.
filter cake. Solids from the drilling mud deposited on the borehole wall as the water phase is lost into the
formation.
fish. Portion of the drill string left in the borehole. See also fishing, string failure.
fishing. An attempt to retrieve the portion of the drill string left in the borehole. See also fish, string failure.

flow-meter method. A procedure used to measure flow rate using a turbine-type flow meter.

foamer. Substance used in air rotary drilling to enhance the air's ability to carry cuttings and reduce the velocity
required to clean the borehole.
foot piece. A device at the end of an air pipe that breaks the air into small streams so that bubbles that are
formed are as small as possible.
foreign humanitarian assistance (FHA). Programs conducted to relieve or reduce the results of natural or
man-made disasters or other endemic conditions such as human pain, disease, hunger, or privation that might present a serious threat to life or that can result in great damage to or loss of property. Foreign humanitarian assistance provided by US forces is limited in scope and duration. The foreign assistance provided is designed to supplement or complement the efforts of the host nation civil authorities or agencies that may have the primary
responsibility for providing foreign humanitarian assistance. Foreign humanitarian assistance operations are those
conducted outside the United States, its territories, and possessions. (JP 1-02. Source: JP 3-33.)
formation stabilizer. Material placed on the outside of the screen to help prevent deterioration of the annular
space; using formation stabilizer is an alternative method to using gravel-pack material.
gel-flake. Commercial chemical agent added to mud drilling fluid to prevent it from freezing. See also
aquagel; barite; fibratex; impermex; micatex.
gel strength. Thickness of drilling mud at rest.
geologic structure. Feature, such as a fold, fracture, joint, or fault, that disrupts the continuity of rock units. geyser effect. A result of denser mud in the annular space flowing down the hole and forcing the clean drilling
mud up the drill rods.
going crooked. A deviated borehole. gravel pack. An artificial sand filter. gravity-outflow method. A backwashing method that involves pouring water into the well rapidly to produce
outflow through the screen openings.
helical-rotor pump. A positive-displacement, rotary-screw- or progressing-cavity-type pump designed for
relatively low-capacity, high-lift wells that are 4 inches or larger in diameter.
humanitarian and civic assistance (HCA). Assistance to the local populace provided by predominantly US
forces in conjunction with military operations and exercises. This assistance is specifically authorized by Title
10, United States Code, Section 401 and funded under separate authorities. Assistance provided under these provisions is limited to (1) medical, dental, and veterinary care provided in rural areas of a country; (2) construction of rudimentary surface transportation systems; (3) well drilling and construction of basic
sanitation facilities; and (4) rudimentary construction and repair of public facilities. Assistance must fulfill
unit training requirements that incidentally create humanitarian benefit to the local populace. See also foreign
humanitarian assistance. (JP 1-02. Source: JP 3-57.)
hydraulic conductivity. A measurement of the relative flow of water through a subsurface material; the results
of the measurement are related to the size and spacing of particles or grains in soils or to the number and size
of fractures in rocks.
hydrographic basin (local drainage basin). Subdivision of a regional river basin. The boundaries of
hydrographic basins are usually represented by mountains or hills, which restrict the flow of water, and by low
areas where the water is discharged out of the basin. See also drainage basin; major river basin;
regional river basin.

hydraulic gradient. Slope of the water table. Determines the direction of groundwater flow.
hydrologic cycle. The constant movement of water above, on, and below the earth's surface. igneous rock. Rock that forms when hot molten material (magma) cools or solidifies either inside the earth's
crust or on the earth's surface (lava). See also **lava; magma**.
impermeable barriers. Features (solid rock masses) through which groundwater cannot flow.
impermex. Commercial chemical agent added to mud drilling fluid to prevent it from freezing. See also
aquagel; barite; fibratex; gel-flake; micatex.
infiltration. The absorption of rainwater by the ground on which it falls.
inside-tremie method. Placing grout in the bottom of the hole through a tremie pipe that is set inside the
casing.
jet-drive drilling. A method of constructing small wells in cold climates; the wells are usually 2-inches in
diameter and are drilled to a depth of 200 feet.
jet pump. A combination of a surface centrifugal pump, a down-hole nozzle and a venturi arrangement used in
small diameter wells requiring a lift of 100 feet or less.
jetted well. A well that is dug using a high velocity stream of water. See also wash-in method.
jetting method. A backwashing method that involves using a jetting tool to remove caked drilling mud from
the borehole wall; this method requires a large water supply.
karst topography. Results from the dissolution of carbonate rocks by groundwater and is characterized by
caves, sinkholes, closed depressions, and disappearing streams.
lava. Magma that cools or solidifies on the earth's surface. See also **igneous rock; magma**.
limestone. A carbonate rock that dissolves when carbon dioxide from the atmosphere and groundwater mix to
form carbonic acid.
lithification. The process by which sediments are converted to rock. Lithification includes compaction,
consolidation, cementation, and desiccation.
loss zone. Area where grout is lost into the formation. lost circulation. Volume loss of the drilling fluid returning to the surface. magma. Hot molten rock material. See also **igneous rock; lava**.
major river basin. Largest member in the river basin grouping (e.g., the Mississippi River Basin). See also
drainage basin; hydrographic basin (local drainage basin); regional river basin.
Marsh funnel. Device used to test mud viscosity; the funnel is 12-inches long and 6-inches in diameter, and it
has a No 12 mesh strainer, a 1,500-ml cone, a 2-inch-long calibrated hard-rubber orifice (inside diameter of 3/16 inch), and a 1,000-ml capacity cup.
Marsh-funnel test. Procedure routinely conducted to determine the thickness or apparent viscosity of drilling fluid. measured-container method. A procedure used to determine flow rate from a well or pump by measuring
the time required to fill a container with a known volume.
metamorphic rock. Igneous, sedimentary, or preexisting metamorphic rock that preexisting metamorphic rock
that undergoes further transformation by changes in pressure, temperature or chemistry.
micatex. Commercial chemical agent added to mud drilling fluid to prevent it from freezing. See also aquagel;
barite; fibratex; gel-flake; impermex.
mud pump. A positive-displacement double-acting piston pump with capacities ranging from one to several
hundred gallons per minute at pressures up to several hundred pounds per square inch.
mud rotary drilling. A well drilling method that uses mud to circulate the drilling fluid during the drilling process. open-hole placement. A method of installing gravel-pack material in a well. open-pipe method. A procedure to measure discharge rates using a fully open pipe and measuring the distance
the water stream travels parallel to the pipe at a 12-inch vertical drop.
open-well method. A compressed-air method that involves establishing the surging cycle by pumping from the
well with an air lift and by dropping the air pipe suddenly to cutoff the pumping action.
outside-tremie method. Placing grout outside the casing using a tremie pipe; this method is not recommended
for depths greater than 100 feet.
particle slip. Downward movement of an object through fluid. pendulum effect. Action of creating a straight borehole from a weighted drill string and bit. perched aquifer. An aquifer that lies above an unconfined aquifer and is separated from the surrounding
groundwater table by a confining layer.
percussion drilling. A method of drilling that involves crushing by impact from the teeth of the drill bit
percussion drilling for water wells uses down-hole, pneumatic-percussion hammer drills.
permafrost. Permanently frozen subsoil. See also **continuous permafrost; discontinuous permafrost**.
(JP 1-02. Source: N/A)
permeability. The capacity of a porous rock or soil to transmit a fluid. pH (potential of hydrogen). A negative logarithm of the hydrogen-ion concentration. A value of seven is
neutral. Low numbers are acid; large numbers are alkaline.
pipe clamp. A device used to hold the pipe at any position in the hole during drilling operations.
pitcher pump. A surface-mounted, reciprocating or single-acting piston pump.
playa. Dry lake bed comprised mainly of clay and located in an intermountain valley.
Pogonip. A bioclastic limestone interbedded with olive-gray shale and in the upper 100 meters from the surface
usually has a few beds of reddish-brown quartzite and brownish-gray coralline dolomite
polymer. A water-based, organic, inorganic, natural, synthetic, or synthetically-formulated additive. Polymers
are formulated for various drilling fluid purposes and is used alone or to enhance clay muds. See also E-Z
Mud; Poly-Sal; Revert.

## Poly-Sal. Synthetic, Inorganic Polymer. See Also **Polymer; E-Z Mud; Revert.**

population distribution. Surface indicator that could indicate water availability because of population density.
porosity. The ratio of volume of the pore space, or voids, to the total volume of the soil or rock. potentiometric surface. The surface that water rises to in a casing once hydrostatic pressure is released from
an aquifer.
precipitation. Moisture released from clouds to the earth in the form of rain, sleet, hail, or snow. pressure-pumping method. A backwashing method that involves capping the casing and pumping water into
the well under pressure.
pull-back method. A way of installing telescoping screen.

## Pulldown. See Also **Feed Drive**.

pump-surge method. A backwashing method that involves alternately pumping water to the surface and
letting water run back into the well through the pump-column pipe.
qanat. A man-made, gently inclined underground channel that allows groundwater to flow from alluvial gravels
at the base of hills to dry lowland. Qanats appear as a series of ant-mound-like openings that run in a straight
line and act as air shafts for a channel. See also ant-mound-like openings.
recharge. The replenishment of an aquifer with water.
recharge area. Area where the groundwater reservoir is replenished. regional river basin. Subdivision of a major river basin (e.g., the Missouri River Basin is a regional river
basin of the Mississippi River Basin). See also drainage basin; hydrographic basin (local drainage
basin); major river basin.
reservoir indicators. Characteristics in soils, rocks, and landforms that define the ability of an area to store
and transmit groundwater but which do not directly indicate the presence of groundwater.
Revert. A natural, organic polymer fluid derived from the guar plant. See also **polymer; E-Z Mud; Poly-Sal.**
ringing off. Fatigue failure in the drill-rod joints caused by excessive torque or thrust or by borehole deviation.

riparian vegetation. Dense strands of vegetation along stream channels.

## Rivers. See Also **Streams And Rivers**.

rock development. A well-development method used in rock formations that involves combining jetting with
air-lift pumping to wash out fine cuttings, silt, and clay.
rotary pump. A pump that uses a system of rotating gears to create a suction at the inlet and force a water
stream out of the discharge.
rotary table. Rotating platform on a rotary rig that transmits torque to the drill rod through the kelly. runoff. Precipitation on land surfaces that flows along the surface into streams without infiltrating. sacrificial anode. A simple method of protecting metal casing from corrosion by connecting a galvanically
active metal bar to the casing. See also cathodic protection.
salt encrustation. Surface indicator that often occurs in playas and is indicative of saline groundwater.
saltwater encroachment. Movement of salt water into zones previously occupied by fresh water. saltwater intrusion. Invasion of salt water into fresh water during pumping. sanded in. A condition that exists when the string becomes stuck when cuttings collect on the bit and collar
shoulder.
sand line. Device used with the elevator for lifting one or two half-lengths of pipe. See also **elevator (casing)**.
sandstone. Consolidated or cemented sand.
saturated thickness. Distance between the top of the groundwater and the bottom of the aquifer. sedimentary rock. Rocks that are composed of sediments that are converted to rock through compaction
cementation or crystallization.
self-priming pump. A pump with a priming chamber that makes repriming unnecessary when the pump is
stopped for any reason other than an intentional draining.
semipermeable barriers. Features (faults or fractured rock masses) that restrict water flow but do not act as
complete barriers.
shale. Fine-grained sedimentary rock that does not store much groundwater and does not transmit large
quantities of groundwater.
single-string method of installing casing. Installing casing and screen (already joined) in a single
assembly. See also **single-string method of installing screen.**
single-string method of installing screen. See also **single-string method of installing casing**. smentex. Commercial chemical agent added to mud drilling fluid to prevent it from freezing. See also
aquagel; barite; fibratex; gel-flake; impermex; micatex.
snow-melt pattern. Surface indicator that provides evidence of recharge areas and directions of groundwater
flow.
soil moisture. Surface indicator that provides some indication of recharge and discharge areas; soil moisture
content is related to local rainfall and to grain size.
sounder. Two-conductor, battery-powered indicator used to measure water levels. See also electric-line method.
specific retention. Water that cannot be pumped out of a well.
specific yield. Water that is able to be pumped from a well. spring. Effluence of groundwater occurring where the water table intercepts the ground surface; a spring is a
good surface indicator of the presence of shallow groundwater occurrences.
spudding. Raising or lowering the drill string.
spudding in. Starting the borehole.
squeezing. In-hole effects of swelling soil (shale or clay) that absorbs water from the drilling fluid. See also
swelling soil.
stabilizers. Items, such as a drill collars, used on the drill string during drilling operations.
stave tank. A collapsible and portable 1,000 gallon water container. streams and rivers. Surface indicators that are usually recharge areas in arid regions and may be recharge or
discharge areas in temperate climates; areas adjacent to streams are considered good locations for wells but are
not always the best available areas for water wells because of soil content. See also rivers.
string failure. A condition that exists when the drill string parts, leaving a portion in the borehole. See also
fish; fishing.
submergence. The proportion (percentage) of the length of the air pipe that is submerged below the pumping
level.
submersible pump. A centrifugal pump closely coupled with an electric motor that is operated underwater. submersible-pump method. A pump-testing method that uses a submersible pump to pump test the water well. surface indicators. Features that suggests the presence of groundwater. surface-water divide. Boundary between groundwater flow systems. surge-block method. A backwashing method that involves developing a well by surging water up and down
the casing with a surge block or plunger.
swelling soil. In-hole effects of shale or clay that absorb water from the drilling fluid. See also **squeezing**.
T. A pipe capable of receiving two hoses from either end.

tape method. Procedure to measure the depth to the static level in a shallow well. theater. The geographical area for which a commander of a geographic combatant command has been assigned
responsibility. (JP 1-02. Source: JP 1.)
thixotropic. A substance that is gel-like when still, but liquid when agitated.
top head. A mechanism on a rotary rig that moves down along the rig mast as the boring is advanced and is
raised to the top of the mast to add a length of drill pipe; the top-head drive uses a power swivel.
transmissivity. The product of hydraulic conductivity and the saturated thickness expressed in gallons per day
per foot of aquifer width.
transpiration. The process by which water that has traveled from the ground through the plant's system is
returned to the air through the leaf system.
tremie. A long tube or box used for depositing concrete under water, by a process of continuous filling at the
upper end and discharging at the lower, accomplished by a slight churning motion.
tremie placement. Placing gravel-pack material using a tremie pipe.
tricone bit. A bit that consists of three cone-shaped rollers with steel teeth milled into the surfaces. turbine pump. A shaft-driven, multistage, centrifugal pump containing several impellers or bowl assemblies.

## Uncased-Interval Method. Installing Casing In Wells Located In Rock Formations.

unconfined aquifer. An aquifer that is partly filled with water, has fluctuating water levels, and receives direct
recharge from percolating surface water.
unconsolidated deposit. Consists of weathered rock particles of varying materials and sizes.

unscreened well. A well in competent rock that does not require a screen; the aquifer is tapped through
numerous, irregularly-spaced fractures.
vegetation type. Surface indicator that helps define the location of recharge and discharge areas end
groundwater.
viscosity. In general, the resistance to flow or alteration of shape, by any substance as a result of molecular
cohesion; most frequently applied to liquids as the resistance of a fluid to flow because of a shearing force.
wall stuck. A condition that exists when the alignment of a fine-grained soil or shale hole deviates significantly
and the drill pipe wallows into the wall.
washdown method. Installing screen in an aquifer that is composed of fine to coarse sand with little or no gravel. wash-in method. Installing casing by advancing the borehole for an expedient jetted well construction. See
also **jetted well**.
water table well. A well drilled into an unconfined aquifer. wetlands. Marshes, bogs, and swamps that is indicative of very shallow groundwater. yield. Volume of water discharged from a well per unit of time when water is being pumped or is flowing freely. yield point. Mud quality broadly included in viscosity.

## List Of Acronyms And Abbreviations

| ACC                                        |     |                                                              |
|--------------------------------------------|-----|--------------------------------------------------------------|
| Air Combat Command                         |     |                                                              |
| AFI                                        |     |                                                              |
|                                            |     |                                                              |
| AFMAN                                      |     |                                                              |
| Air Force manual                           |     |                                                              |
| AFSC                                       |     |                                                              |
|                                            |     | United States Air Force specialty code                       |
| AR                                         |     |                                                              |
|                                            |     |                                                              |
| Army Regulation                            |     |                                                              |
| AWWA                                       |     |                                                              |
|                                            |     | American Water Works Association                             |
| BOM                                        |     |                                                              |
|                                            |     | bill of materials                                            |
|                                            |     |                                                              |
| CBRN                                       |     |                                                              |
|                                            |     | chemical, biological, radiological, and nuclear              |
| cc                                         |     |                                                              |
|                                            |     |                                                              |
| cubic centimeter                           |     |                                                              |
| CCDR                                       |     |                                                              |
|                                            |     |                                                              |
| combatant commander                        |     |                                                              |
| cfm                                        |     |                                                              |
|                                            |     |                                                              |
| cubic feet per minute                      |     |                                                              |
| cfs                                        |     |                                                              |
|                                            |     |                                                              |
| cubic ft per second                        |     |                                                              |
| cm                                         |     |                                                              |
| centimeter                                 |     |                                                              |
| COMMZ                                      |     |                                                              |
| communications zone                        |     |                                                              |
| CPM                                        |     |                                                              |
|                                            |     | critical-path method                                         |
| CPS                                        |     |                                                              |
| centimeters per second                     |     |                                                              |
| CSS                                        |     |                                                              |
|                                            |     |                                                              |
| combat service support                     |     |                                                              |
| DA                                         |     |                                                              |
|                                            |     |                                                              |
| Department of the Army                     |     |                                                              |
| DAPS                                       |     |                                                              |
| Document Automation and Production Service |     |                                                              |
| DD                                         |     |                                                              |
|                                            |     |                                                              |
| Department of Defense (form)               |     |                                                              |
| DOD                                        |     |                                                              |
|                                            |     |                                                              |
| Department of Defense                      |     |                                                              |
| DOS                                        |     |                                                              |
| Department of State                        |     |                                                              |
| EI2RC                                      |     |                                                              |
|                                            |     | Engineering Infrastructure and Intelligence Reachback Center |
| ENGR                                       |     |                                                              |
|                                            |     |                                                              |
| engineer                                   |     |                                                              |
| ERDC                                       |     |                                                              |
| Engineer Research and Development Center   |     |                                                              |
|                                            |     |                                                              |
F


Fahrenheit
FEMA

Federal Emergency Management Agency
FFE


field force engineering
FHA


foreign humanitarian assistance
FM


field manual (Army)
fpm


feet per minute
ft


feet
ft/lb


foot per pound
ft/min

feet per minute
gal


gallon
GE


general engineer
gph


gallon per hour
gpm


gallon per minute
GVWR

gross vehicle weight rating
HCA


humanitarian and civic assistance
HHQ

higher headquarters
HQ


headquarters
HN


host nation
HNS


host-nation support
ID


inside diameter
in


inch
ISO


International Standards Organization
ITWD

International Standards Organization air-transportable water drill
JFC


joint force commander
kg


kilogram
kg/cm

kilogram per centimeter
kg/m

kilogram per meter
kPa


kilopascal
kv


kilovolt
lb


pound(s)
lb/ft


pound per foot
m


meter
MEDEVAC

medical evacuation
MCWP

Marine Corps warfighting publication
MILSTRIP

military requisitioning and issue procedure
ml


milliliter
mm


millimeter
mph


miles per hour
N/A


not applicable
NATO

North Atlantic Treaty Organization
NAVFAC

Naval Facilities Engineering Command
NCD


naval construction division
NCF


naval construction force
NEC


Navy enlisted classification
NECC

Navy Expeditionary Combat Command
NMCB

naval mobile construction battalion
NTRP

Navy tactical reference publication
NTTP

Navy tactics, techniques, and procedures
NWP

Navy warfare publication
OA


operational area
OD


outside diameter
OIC


officer in charge
OPS


operations
PM


program manager
POD


print on demand
POL


petroleum, oils, and lubricants
ppm


parts per million
psi


pounds per square inch
psig


pounds per square inch gauge
PTO


power takeoff
PVC


polyvinyl chloride
RED HORSE
Rapid Engineer Deployable Heavy Operational Repair


Squadron Engineers
RFI


request for information
ROWPU

reverse osmosis water purification unit
rpm


revolutions per minute
SCFM

standard cubic foot per minute
SOP


standing operating procedure
Sr


specific retention
STANAG

standardization agreement
STD


standard wall
STP


soldier training publication
STU III

secure telephone unit-third generation
Sy


specific yield
TD


total depth
TEC


Topographic Engineering Center (Army)
TEOC

TeleEngineering Operations Center (DOD)
TM


technical manual
TOA


table of allowance
TOE


tables of organization and equipment
US


United States
USACE

United States Army Corps of Engineers
USGS

United States Geological Survey
UTC


unit task code
WDRT

Water Detection Response Team
WDS

well drilling system
WORMM

worker/oiler/repairman/maintenance/mud man
WRDB

water resources database
XS


extra strong

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## List Of Effective Pages

| Effective Pages              |
|------------------------------|
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| DEC 2008                     |
| 1 thru 20                    |
| 1-1 thru 1-4                 |
| 2-1 thru 2-40                |
| 3-1 thru 3-10                |
| 4-1 thru 4-36                |
| 5-1 thru 5-20                |
| 6-1 thru 6-14                |
| 7-1 thru 7-16                |
| 8-1 thru 8-6                 |
| 9-1 thru 9-6                 |
| A-1 thru A-6                 |
| B-1 thru B-4                 |
| C-1 thru C-4                 |
| D-1, D-2                     |
| E-1 thru E-8                 |
| Reference-1 thru Reference-6 |
| Glossary-1 thru Glossary-10  |
| LOAA-1 thru LOAA-6           |
| LEP-1, LEP-2                 |
|                              |

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## Ntrp 4-04.2.13 Fm 3-34.469 Afman 32-1072