By William E. Godsey, PG

Engineering Geologist - President

Geo Logic Environmental Services, LLC

P.O. Box 1904 

Longview, Texas 75606

bill.godsey@geologicenvironmental.com

903-753-8200
Introduction

As part of the process for evaluating the type of water 

used in hydraulic fracturing, lets ask a few questions:

-Who is concerned about fresh, brackish and saline water?

- Why should anyone be concerned?

-What is important to understand?

-Where is it located?

-When do we need to know about it?
Purpose

The purpose of this presentation is to:

- visit the terms fresh, brackish and saline

- locate the major fresh and saline aquifers

- evaluate various aquifer water qualities

- summarize frac water quality parameters

- discuss groundwater usage

- cover spent frac water management 

(in less than 15 minutes !)
Information Sources

 Records Research

 Well Log Review

 Published Reports

 Economic Data

 Public Records

 State Geologists

 Universities/Colleges

 GIS Mapping

 Private Data Bases

 Regulatory Agency

 Surface Geology

 Groundwater/Soil

 Appraisal/Real Est.

 USGS

 Federal Agencies
What is Salinity?

 Salinity refers to the amount of total dissolved solids 

(TDS) in the water and is frequently measured by 

electrical conductivity (EC), as ions dissolved in water 

conduct electricity and actual TDS analyses are 

expensive to conduct. 

 Waters with higher TDS concentrations will be 

relatively conductive. TDS is measured in parts per 

million or mg/L and EC is measured in micro-Siemens 

per centimeter (μS/cm). 
Water Terms for This Presentation

 A TDS concentration of 1,000 mg/L is a somewhat arbitrary upper limit 

of freshwater based on the suitability of water for human 

consumption. Although water with TDS greater than 1,000 mg/L is 

used for domestic supply in areas where water of lower TDS content is 

not available, water containing more than 3,000 mg/L is generally too 

objectionable to drink. Water with a TDS concentration less than 3,000 

mg/L can be considered fresh water. 

 Water from 3,000-10,000 Mg/L TDS will be considered brackish

 Water in excess of 10,000 Mg/L will be considered saline. 

 Ground water with salinity greater than seawater (about 35,000 mg/L) 

is typically referred to as brine. 
US Fresh Water Aquifers
Food (Water) for Thought

 The volume of water being used for hydraulic 

fracturing is relatively small when compared to all 

other uses for fresh water (golf courses, thermoelectric 

cooling, residential, agriculture, industrial) versus the 

benefit to out nation from natural gas production.

 These are one-time or limited uses.

 There is not a shortage of groundwater. Sometimes 

population demand exceeds the ability of an aquifer to 

deliver the volume of water needed instantaneously.
US Saline Aquifers
A Focus on the Marcellus Shale Area 
Valley and Ridge Sandstone 

Aquifer With Coal Beds
Piedmont Aquifer: Carbonate 

and Fractured Crystalline Rock 
Consolidated Sandstone Aquifers of the 

Appalachian Plateau Province
A View of the Potomac Aquifer in 

the Region of Virginia & Maryland
Variable Water Quality in an Aquifer Based 

on Depth and Areal Extent Across a Basin
Cations- Anions , hydration, crosslinks, polymers, 

breakers, oxidation, interference, delay .... and more 

fun than you ever thought you were going to have 

outside of a chemisty lab, football game or airport!
Frac Fluid

Geochemistry

Additives

Sand Source Water

Temperature

and

Pressure

Rock 

Mechanics

FRAC

Pipe
Parameter or

Compound

Range for Parameter

or Compound

Comments on Impact of 

Parameter or Compound 

on Frac Fluid Performance

pH 6-8.5 units Interferes with hydration of 

polymer, scale

Ca & Mg <2000 ppm

Scale, interferes with 

breakers

Fe <10 ppm

Catalyst for polymer 

oxidation, scale

Ba & Sr <5 ppm

Reducing agents, interferes 

with breakers

Chlorides <40,000 ppm

Interferes w/hydration of 

polymers and breakers

Bicarbonates <300 ppm

With Ca/Mg & heat will 

scale, delay crosslink

Phosphates <5 ppm

Interferes with metal 

crosslinkers

Sulfates <500 ppm

Scales, crosslinker

precipitation
Concerns for Use of Saline 

Water as a Frac Fluid 

Saline ground water has a tendency to precipitate sulfate 

(example rock or mineral precipitate: gypsum), carbonate 

(rock or mineral example: calcite), and silicate scales. The 

tendency of saline ground water to form scale is important 

to its suitability for use in frac water due to the extreme 

temperature and pressure differentials the water will 

encounter during use. Knowledge of the compounds 

present in the water prior to use is an important factor. 
Concerns for Use of Saline 

Water as a Frac Fluid (continued)

Use of saline water as a frac fluid present operating issue 

which must be addressed:

• Transport

• Storage

• Treatment/Management

• Equipment damage

• Spillage
Aquifer Storage of Frac Fluids

Fresh water storage in saline aquifers has been developed for 

many decades as a method of storing fresh water for later 

use in arid areas. Fresh water will perch atop of the brine 

water. Perhaps consideration should be given to this 

concept for frac fluids as well. Where multiple wells are 

being drilled on a single pad, a saline aquifer could be used 

to store fresh or brackish frac fluids for use at a later date. 

The frac fluids could be stored and withdrawn as needed 

from a brine aquifer. Provided the brine aquifer is suitable, 

the aquifer could serve as a source water reservoir as well as 

a storage reservoir.
Advantages of Fresh Water Utilization

 Recycling and reuse of fluid is possible

 Treatment & release to publically owned treatment 

works (POTW) or by NPDES possible

 Evaporation and reuse of salts

 Subsurface injection in permitted wells

 Surface water and groundwater sources available

 Source of revenue to landowners
Advantages of Saline or Brackish Water

 Recycling and reuse is possible

 Treatment and release to POTW or NPDES possible 

but more restricted than fresh water

 Evaporation and reuse of salts

 Subsurface injection in permitted wells

 Potential use for brine aquifer storage and reuse
Summary and Conclusions

 The type and concentration of TDS in the water used 

for frac work is important for a successful completion.

 Ba, Sr, Fe and phosphates (not chlorides) appear to be 

the major limitations to using non-potable water for 

hydraulic fracturing operations.

 Water quality in aquifers across the country is variable 

and combined use of waters from multiple sources 

may be required in some areas.

 Volume of fresh water used is small in comparison.

 Recycling, reuse and subsurface aquifer storage of frac

fluids may provide workable methods for fracs. 
Summary and Conclusions

 Groundwater of all types is plentiful

 Treatment and utilization of non-potable sources of 

water may be a viable options

 Management of waters while being utilized and spent 

waters must be taken into consideration

 We must all be cooperative and creative with our 

natural resources if we are to continue to develop 

clean, dependable energy resources for our nation.