bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory Evaluation of In-Situ Stress Contrast in Deeply Buried Sediments
Authors: Abou-Sayed A. S.
Published: December 2007

Delineation of the effects of in-situ stress contrasts on fracture containment requires the field measurement of the minimum horizontal in-situ stress of the pay zone and adjacent layers. Small hydraulic fracturing tests are presently the most practical method with which to determine the state of stress acting at great depth within the earth.

Several attempts have been made to correlate the state of stress of a rock layer and its current mechanical properties. Recently techniques for the independent determination of P- and S-waves during wellbore logging have been implemented by the logging service industry. Such advances help establish a more reliable value for the in-situ rock elastic properties, namely Young's modulus and Poisson's ratio. Higher Poisson's ratio value has been proposed as an indicator of higher minimum horizontal in-situ stresses. This is compatible with trends for reservoirs in the Louisiana/Gulf of Mexico area where clean sandstone pay zones are prevalent. Burial history and rock constituents may alter such conclusions.

Although correlation with Poisson ratios of the various formations may provide rough estimates of horizontal stress gradients, they are inadequate to ascertain which of two adjacent formations has the higher horizontal stress, especially in tight reservoirs where the clay content in the sandstone layers is high and the differences between sandstone and shale layers diminish. Inelastic deformation, as well as changes in material properties and strain during the burial history have a significant influence on today's state of stress at depth. Furthermore, correlation of direct in-situ stress measurements with general laboratory response of granite, sedimentary rocks and salt formation to applied loads imply that soft, high ductility material (higher principal strain ratio during inelastic flow) as well as materials not capable of sustaining large deviatoric stress (low ratio of deviatoric stress to mean stress in uniaxial strain deformation) possess higher minimum horizontal stresses (cf. Abou-Sayed, et al., 1981).

In the absence of direct, field-measured in-situ stress data, special laboratory tests are presented here with analysis to provide a suggestive basis for evalution of in-situ stress contrast within different layers for fracture containment analysis. The laboratory tests presented in this paper are aimed at providing the mechanical properties of the rock layers under two deformation histories: 1) triaxial compression tests to determine the elastic moduli of rocks, and 2) one-dimensional (uniaxial) strain tests to delineate the long-term correlation between horizontal and vertical stresses within the various layers. Tests to measure the coefficient of thermal expansion of rocks under simulated in-situ conditions may also be performed.

The laboratory-deduced stress contrasts in various rock types are compared to field-measured data. Several case studies are presented and close agreements are observed.
The Petroleum Industry and the European Economic Community
Authors: Matthiessen Hans Heinrich
Published: December 2007

Introduction

World War II left the economies of large parts of Europe in a state of devastation. The population had sustained heavy losses in life. A huge number of industrial plants and homes lay in rubble. Monetary systems had broken down. Europe's political and economic structure was materially changed by the erection of an "Iron Curtain" between the Eastern and the Western half of the continent. Reconstruction began with the production of basic necessities - food, clothing, homes. It formed the basis for the reversal of the downward trend in European economic development. Two circumstances were responsible for the success that in the free part of Europe the rehabilitation could be implemented: first, the possibility of developing under a free enterprise system and, second the Marshall-plan aid which the United States had offered to all countries in Europe, but which, most regrettably, only the free countries in Europe were in a position to accept. To this day the free Europeans are deeply grateful for this real and timely help by the American people. It did not take long for Europeans to realize that sustained economic growth and political harmony could be maintained by the creation of economic and political unity for Western Europe. One group of European countries formed E.E.C., the European Economic Community. This area is shown on Fig. 1. The countries representing the group of countries which founded a somewhat looser organization, EFTA, the European Free Trade Association are also shown. Let me add that, together, EFTA and E.E.C. encompass about 85 percent of the population of free Europe. In 1962. the EFTA countries had about 91 million inhabitants as compared to 176 million in the Common Market area as shown in Table 1. Many people in Europe hope that the day will come when a merger between E.E.C. and EFTA will occur and one great European Economic Community will be established. This, of course, is going to he a lengthy, difficult process.

THE COMMON MARKET AND ECONOMIC GROWTH

The Common Market became the core of the European Economy. In the so-called Rome treaties of 1957 the six E.E.C. partners agreed that by 1969 at the latest, all tariffs will have to be abolished in the trade among member countries and uniform tariffs will believed in the trade with non-member countries. Also, an effort will be made to harmonize the tax systems of the member countries. A further step which has not yet been worked out in detail would be the creation of a uniform currency system for the Common Market. In the other fields as well, definite measures have been agreed upon. For instance, a large degree of uniformity was established in antitrust legislation.

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Simulation of Gas Production From a Reservoir Containing Both Gas Hydrates and Free Natural Gas
Authors: Holder Gerald D. , Angert Patrick F.
Published: December 2007

A three dimensional finite-difference simulation of heat and mass transfer in a reservoir containing stratified layers of gas hydrates (50 ft.) and free natural gas (50 ft) was made. Results indicate that in this volumetric depletion gas reservoir, hydrated gas can contribute about 20 to 30% of the total gas production. This is due to hydrate dissociation as the pressure in the reservoir is reduced. These percentages represent an estimate for a gas reservoir which is produced at the rate of 2.5 MMCFD. The thermal capacity of the reservoir is more than sufficient to provide the energy necessary for hydrate dissociation into gas or water.
Another Concept for Final Buildup Pressure
Authors: Mead Homer N.
Published: December 2007

A method is developed for determining final static reservoir pressure buildup based upon the assumption that the change of the quantity [Ps - Pw] decreases at a constant rate with time. It is actually an application of the infinite series. The pressure measured in the well is assumed to be the average static reservoir pressure less the additive effect at any one time of the differential in pressure across the skin, differential in pressure between the higher permeability parts and the surface of the rest of the reservoir bounding them and differential in average pressure at the boundary of the higher permeability parts and static reservoir pressure. Thus the actual plot of the log [Ps - Pw] may be the addition of several straight line functions at any one particular time. A great deal of field data has been analyzed using this method; results indicate that it is capable of giving accurate results in every case. Other information besides final static pressure buildup may be obtained from the plot of log [Ps - Pw] vs shut-in time.

The method presented in this paper has the following advantages:The time the well is produced prior to shut-in is not required.The skin effect or damage ratio can be observed from the plot of log [Ps - Pw] vs shut-in time at a glance.A qualitative measurement of the effect of the non-uniformity in permeability of the reservoir can be made.

Introduction

In 1937, M. Muskat proposed that the log of Ps - Pw would form a straight line when plotted against shut-in time during pressure buildup.
Vertical, Conformance in an Alternating Water-Miscible Gas Flood
Authors: Stone Herbert L.
Published: December 2007

Oil recovery by the injection of water alternately with gas (WAG flooding) is often limited by gravity segregation, which causes the injected gas to rise to the top of the formation and water to migrate to the bottom. This segregation results in a miscible flood in only a thin layer at the top of the formation, whereas the remainder is waterflooded. However, vertical conformance in a WAG flood can be greatly improved by use of injection rates that are high relative to well spacing. The degree of improvement and, hence, the resultant oil recovery is primarily a function of a single dimensionless parameter, which is one form of the viscous-gravity ratio.
Dual Porosity CNL Count Rate Processing
Authors: Scott H. D. , Flaum C. , Sherman H.
Published: December 2007

The standard method of computing porosity for the two-detector Compensated Neutron Log (CNL) is to use the ratio of near to far detector count rates. This procedure has the advantage that, to first order, environmental effects tend to cancel, leaving only residual effects to be corrected using a series of departure curves.

Recently, a new four-detector Dual Porosity CNL tool has been introduced which uses two epithermal neutron detectors in addition to the two standard thermal neutron detectors. Two separate porosity measurements are thus obtained, one from each pair of detectors. In clean formations, the measured porosities agree. However, in shaly formations containing high neutron absorbers the porosity measured by the epithermal detectors reads lower and agrees more closely with density derived porosity.

To maintain reasonable count rates, the epithermal detectors are spaced closer to the neutron source than the thermal neutron detectors. If ratio processing is used for the epithermal measurement, the computed porosity is more sensitive to borehole effects indicating a greater difference in the response of each detector to the borehole environment. As a result of a detailed study of the tool response to many environmental variables, a new data processing technique has been developed using individual detector count rates. The method is analogous to the "spine-and-ribs" analysis developed for the FDC tool.

Parameters which have been studied are borehole size, tool standoff, mudcake thickness, mud weight, borehole salinity, formation salinity, formation matrix, formation gas, temperature and pressure. Examples are given of how some of these parameters affect the individual count rates.

The new processing method can be used to compute both epithermal and thermal neutron porosity. In the latter case, however, additional input parameters relating to neutron absorbers should be specified. Count rate processing has two important advantages. First, it can provide a value of porosity much less sensitive to variations in borehole parameters, particularly tool standoff for the epithermal measurement. Second, the deviation of a data point from the spine can be a measure of the effective tool standoff. This parameter can be used as a basis for an adaptive filter of the neutron porosity. Examples illustrating the improvements obtained with count rate processing are presented.
Simulation of the LETC/DOE TS-1S Steam Drive Experiment
Authors: Hutchinson H. L. , Kennedy J. H. , Johnson L. A. , Fausett D. W.
Published: December 2007

In conjunction with the LETC/DOE TS-1S Test, a computer simulation study was performed to a) help define the pattern size and configuration prior to the test, b) monitor the progress of the test during its operation, and c) help with post-test interpretation of the results. A multidimensional steamflood model was used to conduct the simulation. Results helped to define the inner and outer pattern sizes for the inverted 5-spot pattern. During the test vertical temperature profiles were matched which suggested significant under-running of the zone. Post-test coring and matching tended to confirm this behavior and the model also showed that initial oil saturation heterogeneity controlled the fluid movement during the experiment. The model results suggested that about three-fourths of the injected steam left the zone of interest and that fluid movement continued after the test was terminated. Studies of pre-steamflood air injection testing showed that such testing can give indication of areal heterogeneities so that steam movement during the test can be anticipated based on such heterogeneities.
Preliminary Findings From a Study To Perform Automated Metering and Control of Carbon Dioxide Injection With a Liquid Turbine Meter
Authors: Grassbaugh David P. , Kearney Carroll L. , Crane Tom L.
Published: December 2007

With the advent of tertiary flood projects utilizing CO2 as an injection medium, the need to adequately measure and control it becomes imperative for achieving optimum injection to withdrawal ratios. Maintaining an optimum ratio is particularly important in the economic sense considering that the injection medium initially would not be available as a by product of production.

Preliminary data compiled from a study to perform automated volumetric metering and injection rate control of CO2, using the liquid turbine meter is presented in this treatise. Observations of CO2 flow within a temperature range of 29-104 deg/f and a pressure range of 950-1250 psig are made for two one-inch liquid turbine meters. The compiled data depicts measured turbine meter accuracy variations which may be controlled to within 6% of true flow by correction formulas that may be solved by digital or analog techniques.
Results of the Bell Creek Unit ‘A’ Micellar-Polymer Pilot
Authors: Aho Gary E. , Bush Jim
Published: December 2007

Gary Energy Corporation has conducted a DOE cost-shared micellar-polymer pilot in the Bell Creek Field, Powder River County, Montana. This project was initiated in 1976 and has progressed through all phases (reservoir evaluation, continued secondary, process design, chemical injection and tertiary response) necessary to allow for a final evaluation.

Unexpected reservoir heterogeneity in the pilot area and the delivery of less-than-design quality sulfonates appear to have affected the chemical flood efficiency. Oil recovery in the confined portion of the pilot is expected to be 28% of the oil-in-place at the start of process injection. Approximately 40% of this recovery is considered to be incremental tertiary.

A summary of all aspects of the pilot will be presented including reservoir geology, chemical flood process design, computer simulation studies, process injection, oil treatment problems and an analysis of overall project performance.
Design, Performance, and Evaluation of the Uniflood Micellar-Polymer Process—Bell Creek Field
Authors: Holm L. W.
Published: December 2007

Gary Energy Corporation conducted a DOE cost-shared 40-acre Demonstration Pilot project to determine whether or not micellar-polymer flooding is a feasible technique to enhance oil recovery from the Bell Creek Field, Montana. The regular line drive waterflood in Unit ‘A’ on 40-acre spacing was terminated in the pilot area in October 1976 when it reached its economic limit according to oil prices and operating costs in effect at that time. The 40-acre pilot 5-spot was developed by infill drilling four injection wells in 1977; thus, the 40-acre pilot is embedded in a 160-acre (9 producers) drainage area located in a waterflooded portion of the Unit ‘A’ reservoir. The reservoir is sandstone with an average net pay of 6.4 feet, air permeability of 1050 md, and water TDS of 3500 ppm.

Water injection into the new 40-acre 5-spot pilot pattern began in October 1977 and was to be followed immediately by the micellar-polymer process. However, the complex reservoir definition work extended this pilot 5-spot waterflood to fifteen months, through January 1979. The micellar-polymer (Uniflood) process commenced in February 1979 with preflush injection (16.4% PV); micellar slug injection (3.8% PV) began August 1979 and polymer injection (100% PV) began October 1979. The average remaining oil saturation in the 40-acre was estimated to be 30.5% at the start of chemical injection.

This paper includes a summary of the micellar-polymer process design, the micellar-polymer oil recovery results projected to project completion, an analysis of the geology and fluid chemistry within the pilot area, and an interpretation and evaluation of the overall performance of the project.

The oil recovery results for the 40-acre 5-spot pilot project are given below for two time frames, necessitated by the 15 month infill 5-spot waterflood. From the start of the micellar-polymer process injection, February 1979, through its projected completion in December 1983; Tertiary oil recovery is projected to be 33.6% of the oil in place as of February 1979.The chemical efficiency of the process is projected to be 11 pounds of sulfonate per barrel of oil recovered.From the start of the infill 5-spot waterflood injection, October 1977, to micellar-polymer process completion in December 1983; The total oil recovery from the 40-acre area is projected to be 45% of oil in place as of October 1977.

A high pH preflush and the use of a chelating agent in the micellar slug minimized the effects of the multivalent ions present in the reservoir. Also, adjustments in the components used in the soluble oil slug made it possible to regain a favorable phase relationship with the reservoir fluids despite the lower-than-design quality sulfonates.
Predicting Reserves And Performance Of A Peripheral Waterflood
Authors: Cowan Robert W. , Guerrero E.T.
Published: December 2007

Publication Rights Reserved

A method to predict the reserves and performance of a waterflood utilizing peripheral injection is developed. It is a modification of the method used by Prats, et al. to predict the reserves and performance of a five-spot waterflood system. Both theoretical and experimental work are involved in the procedures.

Experimental data obtained by Prats, et al. for the five-spot system and by Dyes, Caudle, and Erickson for a direct line drive system were modified for use in the peripheral system. Theoretical procedures are used to predict injectivity prior to fill-up. After water breakthrough, injectivity is predicted from experimental data. The method presented is believed to be more accurate for predicting reserves and performance of a peripheral waterflood than methods utilizing a constant injection rate or methods not considering the buildup of an oil bank ahead of the water front.

Introduction

Waterflooding by peripheral injection is becoming more common. This is due, in most cases, to allowable restrictions or to the practice of initiating water flooding in the early life of a field to maintain pressure at an optimum point. If a sufficient rate of water injection can be maintained through a peripheral system, it will usually be selected over a pattern type system because of the lower initial investment and operating expense. A review of material available, both analytical and empirical, to assist in the prediction of waterflood performance indicated that a wealth of information 3,4,5,6,7,8,9,10,11,12,13,14 had been published on the five-spot pattern waterflood but very little 15,16 was available on the peripheral system. It was decided to determine if some of the material available on the five-spot could be modified for use in the peripheral system.

METHOD OF PRATS, MATTHEWS, JEWETT and BAKER

Prats et al devised a comprehensive method of predicting the reserves and performance of five-spot waterfloods. Their method takes into consideration more variables than most other accepted methods and was therefore selected for modification to enable prediction of reserves and performance of a waterflood utilizing a peripheral injection system.

Prats et al. based their method on being able to accurately predict injection rates over the life of a waterflood. Both theoretical and experimental work were performed to develop a method for computing injection rate. This method not only assumes that injection rate into a layer is proportional to the permeability capacity, but also takes into account the effect of the water and oil banks and the fluid mobilities within each of the banks. It involves primarily the prediction with time of the rate of injection into and the type of production from each individual layer.
A Further Analysis of the Steam Stimulation of Heavy-Oil Wells and Reservoirs
Authors: van Lookeren J.
Published: December 2007

The application of steam stimulation of wells in oil fields in Venezuela and in the U.S.A. has a history of more than 20 years. Some of the more critical aspects of production rate increase and increase of ultimate recovery of heavy oil have been reconsidered. The earliest large scale project in Venezuela has produced since 1964 with much additional oil and is still producing economically. Its performance analysis has shed some light on reservoir compaction and solution gas drive as drive mechanisms in heterogeneous sands. Applications of steam stimulation with different drive mechanisms such as steamdrive, waterdrive and gravity drainage, have been carried out. Parameters affecting production rates and the decline rates are now better defined and quantified. Obviously injection of steam in wells for production can stimulate both well PI's and oil producing mechanisms.

Approximate steam-soak well models taking into, account stimulation of reservoir mechanism are made and represented by simple mathematical expressions for use in practical planning systems and reservoir performance simulations.
Dynamics of Moving Interfaces in Porous Media: II. Pistonlike Displacement
Authors: Kale Dilip M.
Published: December 2007

A fluid-fluid interface is formed when oil in porous media is displaced by another fluid, say water, in a pistonlike manner. This interface is in the shape of a closed curve surrounding the injection well. The exact manner in which the size and shape of this interface changes with time depends upon the well configuration, rates and the mobility ratio. A general method for tracing the time development of such an interface is presented in this paper.

A complex velocity potential for the flow at any instant is expressed by the superposition of the potentials due to the sources (injection wells), sinks (production wells) and the vortex sheet developed along the interface. Vorticity along the vortex sheet is obtained as a solution to an integral equation derived in the previous paper. From the complex velocity potential the velocity field in the flow region at that instant is known. Then by using Kelvin's relation for the motion of a surface in a moving fluid the progress of the interface for small time interval δt is traced. By repeating these steps the complete time development of an interface is traced.

An impervious no-flow boundary affects the flow and thus contributes to the velocity potential. Across this boundary the mobility ratio is infinite since the mobility in the exterior region is zero. The contribution to the complex velocity potential of such a boundary is accounted for by replacing it with the appropriate vortex sheet.

The working of the method is demonstrated by implementing the calculation scheme for some simple patterns such as two spots and five spots. The results obtained are in good agreement with the known analytical results for the case of unit mobility ratio and with experimental results for other mobility ratios.
Santa Rosa Tar Sands Project
Authors: Randall John S.
Published: December 2007

The Santa Rosa Tar Sands Project involves strip mining of a surface deposit of oil impregnated sandstone at Santa Rosa, New Mexico. The ore is delivered to an extraction plant where it is crushed and the oil extracted using solvent and hot water. A clean damp sand residue is to be returned for back filling the mine (apart from the flue gases involved in untility requirements).
The Use of Supercomputers in the Search for Oil
Authors: Yang Rosa L.
Published: December 2007

Over the last decade, there have been significant advances made in the geophysical processing and reservoir simulation techniques. With these advances comes a rapidly increasing computing power requirement -- especially in the areas of 3-dimensional seismic processing and reservoir simulation model studies. In response to this need for high computing power is the development and application of supercomputers for the energy problem solution. The use of supercomputers is now required in both the exploration for and the exploitation of oil and gas worldwide.
Enhanced Oil Recovery Data Base Analysis by Simplified Predictive Models
Authors: Ray R. M. , Wesson T. C.
Published: December 2007

The U.S. Department of Energy, Bartlesville Energy Technology Center (BETC), has been developing computerized data bases and simplified predictive models to be used to predict enhanced oil recovery (EOR) potential in the U.S. The development phase of this work is nearing completion whereupon the models and data bases will be made available to the public.

This paper describes the overall development phase for the models and data bases with analyses of selected EOR projects using the predictive models. Examples of model outputs are discussed and brief descriptions of the predictive algorithms are given.
Prospects for Gas Imports in the U.S. Energy Market
Authors: Burns David H.
Published: December 2007

In addition to domestic considerations, future levels of gas imports into the U.S. market will be shaped to an important extent by the policies of gas exporters. Exporters must understand that the U.S. will remain one of the world's major gas producers for the foreseeable future and that U.S. import needs will be modest in relative terms compared to those of other industrialized countries. The history of U.S. gas imports from Canada and Algeria makes clear that imported gas must be competitively priced with other available energy sources and that market forces will be a central element in determining the level of imported gas.
Comparative Analysis of Coverage for Oil and Gas Loans
Authors: Castle G. R.
Published: December 2007

One very important task in connection with any oil and gas loan is to determine a loan value and structure the terms in such a way that the property supporting the loan provides an adequate coverage to assure a payout for the lender. After the lender has completed the analysis or appraisal of the reserves and prepared a revised projection based on the lender's own assumptions, most banks use that revised projection as a basis for computing various coverage ratios and tests in order to determine whether the property is adequate collateral for the loan. This paper shall examine on an anonymous basis a sample of 15 oil and gas loans that have been made within the last two years in an attempt to provide insite into what the current standards are for this type of loan.

For the purposes of this analysis eight different commonly used ratios and other tests have been computed for each of these 15 sample loans and the results of these computations have been summarized on Tables I and II. All of the loans chosen for this sample have been syndicated among a banking group, and in each loan the banks have assumed the project or reserve risk. In the computation of these ratios, no attempt has been made to revise the projections that have been furnished by the borrower (in the Information Memorandum) for each of these loans except that all interest computations and present values have been determined at a rate of 14% per annum. As a result, the comparisons shown on Tables I and II may be distorted to some extent by any variation in the assumptions that have been made in the preparation of the economic projections for each of these 15 sample loans. However, later in the conclusion section of this paper there is a discussion of the sample loans in order to point out any assumptions that differ in a significant way from the normal criteria that most banks require in connection with this type of loan.

In the next section there is a definition of the way that each of these ratios has been computed.
Econometric and Resource Modeling Methodology for Projections of Cost of Development of U.S. Natural Gas Potential
Authors: Gangwar Anshumali , Kent H. C. , Schuenemeyer J. H. , Guzman Jaime , Snow Stuart
Published: December 2007

Periodic estimates of the quantity and geographic location of the potential natural gas resources remaining to be discovered, developed and produced in the United States have been made by the Potential Gas Committee, These estimates, however, cover a wide range of geographic conditions, depth subdivisions and variations in the cost of exploration and drilling. The principal objective of this study, sponsored by the Gas Research Institute and the Electric Power Research Institute, is to develop an econometric and resource modeling methodology to evaluate the relative costs of development of the natural gas resource potential which has been estimated by the Potential Gas Committee, and to present these relative cost data in such a way that meaningful comparisons can be made between alternate resources of natural gas. The economic investigations in this study have been concentrated upon two main components: a drilling cost model and a discovery process model. A modification to a previously developed model has been prepared to estimate the discovery rates of natural gas based upon the Potential Gas Committee estimate of ultimate natural gas resource and the previous exploration history (actual or analog) of a geological province. The econometric model will be calibrated by comparisons with the subjective estimation of resource distribution by Potential Gas Committee members, and a consensus discovery rate would be derived. The drilling cost model will be used to translate the exploratory and development efforts into present constant dollars.
Forecasting Supplies of Oil and Gas from America's Offshore Frontier Areas
Authors: Janney Asa M.
Published: December 2007

The Frontiers Model was developed by ICF Incorporated1 to forecast oil, natural gas, and natural gas liquids production from federal offshore areas in Alaska and along the Atlantic and Pacific Coasts. The Frontiers Model forecast does not include future discoveries of proved reserves in the Gulf of Mexico because many other forecasts for that more mature offshore area are available. However, just as production of hydrocarbons, particularly natural gas, from the Gulf of Mexico have become a significant fraction of total national production, the vast, relatively unexplored offshore frontier areas could become an important source of the country's future energy needs.
Problems in the Natural Gas Industry—Causes and Responses
Authors: May H. S. , Mathews C. D.
Published: December 2007

There is general agreement that the natural gas industry currently faces serious problems. Historically, this is not surprising. Natural gas has long been the subject of regulatory and legislative adjusting, fixing and tinkering. The current public debate over natural gas, however, is distinguished by much disagreement as to just what problems the industry faces and, not surprisingly, what the appropriate remedies might be.

This paper will attempt to identify and describe the problems currently confronting the natural gas industry. The paper will comment on the legal and policy implications of these proposed remedies. Finally, it will outline regulatory and legislative solutions now being considered by Congress.
Operator/Contractor Relationships—The Consultant's Role
Authors: Beall J. E.
Published: December 2007

For about $10 anyone can become a drilling consultant. That's how much it costs to print a name and the word "consultant" on a business card. If one has a telephone and a few idle friends he might have the card printed with the words "Drilling Consulting Company". There are at least 110 companies registered in oil industry directories in the Gulf Coast area alone offering drilling consulting services.

How does one qualify to become a drilling consultant? There is no formal examination, no licensing procedure, no code of ethics nor any standards for professional practice. Not a single drilling consulting company is a member of ACME, the Association for Consulting Managing Engineers.

Without any professional society or other mechanism for policing itself, the drilling consulting industry has earned a widespread reputation for greed and incompetence. The drilling boom of 1976–1981 attracted many people into consulting whose only qualification was their willingness to endure isolation at the well site for long periods. Many of these people lacked the tools to manage, engineer or supervise a safe, cost effective drilling operation. Many misrepresented their capabilities when selling their services. A few compounded this dishonesty with kickbacks and thievery.
The Minimum Area Rig Concept—A Unique Bootstrap Drilling Rig
Authors: Kerry C. W. , Lynch S. C. , Armstrong J. E.
Published: December 2007

The Minimum Area Rig Concept (MARC) is a cost-effective alternative to the typical self-contained platform rig. The MARC rig has been developed to provide a 16,000-ft rated drilling rig which can rig up in a limited area of approximately 75% of the original platform drill deck. The rig can also be moved without a derrick barge. The MARC rig was designed by an engineering consultant and is being built to drill and workover wells for ARCO Oil and Gas Company (ARCO) in the Gulf of Mexico, starting in the South Pass Block 61 field.
Long-Range Planning Assures Success of Bering Sea Drilling
Authors: Lewis S. K.
Published: December 2007

To successfully drill in remote and harsh environment areas, a wide variety of specialized equipment, material and personnel must be mobilized in an orderly manner. Long-range planning consisting of environmental assessment, engineering studies, logistical analysis, equipment selection, and operations scheduling must be accomplished prior to operations. ARCO Alaska, Inc., utilized long-range planning methods in preparation for a three-well Bering Sea drilling program.
Blowouts—A Computer Simulation Study
Authors: Thomas D. C. , Lea J. F.
Published: December 2007

A computer simulation study of blowouts was made using a program written earlier. This study shows the predicted effects of various sized kicks on a given wellbore configuration and studies the major variables affecting kick severity in both water- and oil-based muds. The variables include reservoir variations (pressure, permeability, porosity, temperature) and pumping rate at the surface.

Results are shown for the effects of each of these variables on an uncontrolled kick. The present program does not include control procedures but does include some examples of flow through a choke. It was intended to show what might happen if no control procedures were initiated and to study the lower limits of kick detectability. Practices are suggested that should make earlier detection of a kick possible so that conventional kill procedures will be more effective. Blowout simulations suggest that pit gain is the most reliable indicator of a kick. It is recommended that pit level measurement systems, capable of detecting a pit gain of less than 5.0 barrels in the entire active mud system, be developed and be used where high pressure kicks are common.
Calculation of NMDC Length Required for Various Latitudes Developed From Field Measurements of Drill String Magnetisation
Authors: Grindrod S. J. , Wolff J. M.
Published: December 2007

One possible source of error in magnetic surveys is ill based charts used for selecting the required length of non-magnetic drill collar (NMDC). Based on theoretical considerations and measurements of pole- strength values in the field, well-defined charts can be constructed for the selection of the minimum required NMDC length for a specific bottom hole assembly and acceptable azimuth error.
Design and Application of Softer Formation Tungsten Carbide Rock Bits
Authors: Newman E. F.
Published: December 2007

Life of the tungsten carbide tooth rock bit was greatly increased by the introduction to the industry of the O-ring sealed journal bearing design in 1969. With this development greater emphasis was then placed on cutting structure development. Innovative tooth shape designs and metallurgical improvements have allowed the application of carbide tooth rock bits to be extended into softer and softer formations.

Continued bearing development has resulted in more consistent bit performance and a greater tolerance for higher rotary speed. This and the introduction of softer carbide tooth cutting structures have provided the impetus for the industry conversion from steel tooth to carbide tooth rock bits. J22 class bits (IADC Code 5-1-7) have proved to be economical in a wide range of soft formations. Performance from the new J11 class bits (IADC Code 4-3-7) also shows promise of improving the economics of drilling even softer formations. Drilling rates in excess of 100 feet per hour have been obtained in some applications. The design, development, and application of these new products will be discussed in this paper.
Cleanup of Oilfield Wastes in an Environmentally Acceptable Manner
Authors: Wentz C. A. , Shiver C. M.
Published: December 2007

Treatment and disposal of drilling muds and hazardous wastes has become a growing concern in the oil and gas industry. Present disposal methods are either environmentally ineffective or increasingly expensive to use. Society's environmental protection opinions as well as rising trucking costs indicate a need for more effective and economical methods. Newpark waste treatment systems has developed an innovative technology which through field testing has proven to be both cost effective and environmentally acceptable.
Optimizing Motor Drilling System
Authors: Emery M. M.
Published: December 2007

A systems approach to downhole motor drilling is a key concept in optimizing motor performance in extended interval drilling applications. Understanding the interplay of system variables, including bits, motor, stabilization and hydraulics, is the springboard to planning and implementing a motor drilling system for optimum results. Computer programs have recently been developed to facilitate more comprehensive analysis of system hydraulics, to pinpoint possible problem areas and to access motor performance.
Surge and Swab Modeling for Dynamic Pressures and Safe Trip Velocities
Authors: Lal Manohar
Published: December 2007

Surge and swab pressures, which could cause lost circulation or gas kicks and blowout, result from running or pulling a pipe in a borehole. Recent downhole measurements indicate that these pressures differ considerably from the pressures anticipated by traditional computational models which compute such pressures on the basis of steady state flow.

In this paper, a new dynamic surge and swab model is presented that is based on the physics of the transient nature of the phenomenon. It treats friction as a distributed parameter and considers various parameters in hole geometry, hole expansion, varying trip velocity, return area for tricone and diamond drill bits, plugged jets, and the mud properties. The computer program for the model not only predicts the maximum surge and swab pressures or their variation with time at various points in the borehole, but also computes the safe maximum trip speed for a specified pressure margin. Computer studies for running a casing, liner, and drill string in several actual wells show the model to have fast computer run times. The results of some of these studies are reported in the paper. The program is both interactive and user-friendly, and is a significant improvement over the existing models.
An Experimental Analysis of Vertical Two-Phase Flow Using a Drilling Mud/Natural Gas Medium
Authors: White J. P.
Published: December 2007

Engineers and scientists are interested in predicting the behavior of fluids flowing in a pipe. Much effort has been directed toward the study of both single-phase (liquid or gas) and two-phase (liquid and gas) flow. This report describes an experimental study of two-phase flow up a vertical pipe using non-Newtonian liquids. A mathematical correlation of the data generated by using various fluids under a relatively wide range of flow conditions yields two equations that predict two variables of interest-the friction pressure gradient and the flowing fraction of liquid in the pipe.
What Happened to the Daywork Contract
Authors: Langston J. V.
Published: December 2007

This paper develops the historical roles of the Drilling Contractor and the Operator by categorizing land wells into areas of difficulty and risks. The first area is composed of shallow wells that are suitable for footage drilling. The second group contains wells, usually medium depth, with some risk and hole problems. The third category includes the high risk, deep wells with high pore pressure and protection casing.

The story behind these categories demonstrates what happened before and during the five boom years of 1977 – 1981. The Operators began to supplement their in-house expertise with consultants. These consultants ran the capability range from excellent to unsatisfactory. The recent high cost of drilling has been attributed to less than perfect planning and execution of those plans stacked on increased costs.

Since January, 1982, the role of footage drilling has been restored in the first category wells. In category 2 wells, the daywork contracts have been replaced by footage and turnkeys to total depth. In the 3rd category, the footage and turnkeys have been extended through landing and cementing the protection casing after penetrating abnormal pressure. It appears that the Operators have traded one consultant for another, the Drilling Contractor.

This paper develops that long term, the responsible Operator will self insure on the high risk wells by drilling daywork. The responsible, surviving Contractor will have to be paid for trouble on each well that can range from 10 to above 30 percent. To the Contractor, it's one contract risk that must be covered long term on every well. Even though the footage and turnkeys have the cosmetic appeal of improving the Drilling Contractor's motivation, the self insured day rate contract is expected to prevail with the Operators who drilled numerous wells. The exception will be operation where footage and turnkeys will be useful to establish a firm price.
A Production and Operation Review of the Khurais Gas Lift Project
Authors: Chornoboy G. M. , Engelhardt H. W.
Published: December 2007

For development of the Khurais field, gas lift was selected for its inherent flexibility and applicability to high flow rate wells. After one year of operations, the severe desert environment and oversized gas choke valves have proven to be major problems. The downhole equipment has mostly performed well and problems have been diagnosed using surface pressure recording charts. Most wells appear to be producing up to expectations but maximum flow rates have not been explored completely.
Seismic Lateral Prediction in Chalky Limestone Reservoirs Offshore Qatar
Authors: Rubbens I. B. H. M. , Murat R. C. , van Keulen J.
Published: December 2007

Following the discovery of non-structurally trapped oil accumulations in Cretaceous chalky reservoirs on the northern flank of the North Dome offshore QATAR, a seismic lateral prediction study was carried out for QATAR GENERAL PETROLEUM CORPORATION (Offshore Operations).

The objectives of this study were:

to assist in the appraisal of these oil accumulations by predicting their possible lateral extent; to investigate if the technique applied could be used as a basis for further exploration of similar oil prospects in the area.

Wireline logs of eight wells and some 1000 km of high quality seismic data were processed into acoustic impedance (A.I.) logs and seismic A.I. sections. Having obtained a satisfactory match of the A.I. well logs and the A.I. of the seismic traces at the well locations, relationships were established by the use of well log data which allowed the interpretation of the seismic A.I. in terms of reservoir quality.

Measurements of the relevant A.I. characteristics were then carried out by computer along all seismic lines and porosity distribution maps prepared for some of the reservoirs.

These maps, combined with detailed seismic depth contour maps at reservoir tops, lead to definition of good reservoir development areas downdip from poor reservoir quality zones i.e. of the stratigraphic trap areas, and drilling locations could thus be proposed.

The system remains to be adequately calibrated when core material becomes available in the area of study.
Operating an Onshore Sour Gas Field in Abu Dhabi
Authors: Morsi K. M. , Constantini N. M.
Published: December 2007

There is considerable interest in producing deep high pressure reservoirs that contain substantial amounts of sour gas. As a result of the high pressure and sour production involved, it is necessary to incorporate high - strength tubular materials and safety features such as surface controlled sub-surface safety valves, downhole packers and chemical injection system into the completion design.

The use of such a completion concept requires larger hole sizes and heavier casing strings than have previously been used by other operators in the same area.

The experience gained from producing wells in such a gas reservoir is now being applied to the design and completion of wells in a new gas reservoir with a higher percentages of Hydrogen Sulphide and Carbon dioxide.
A Review of the Arun Field Gas Production/Cycling and LNG Export Project
Authors: Alford M. E.
Published: December 2007

The Arun field was discovered by Mobil Oil Indonesia Inc. in late 1971 in its Bee block in the Aceh province on the north coast of Sumatra, Indonesia. Mobil's operations in this area are conducted under the terms of a production sharing agreement with Pertamina, the Indonesian state-owned oil and gas enterprise.

The scope of operations covered by this paper is from production of gas and raw condensate in the field through stabilization and export of condensate and purification, liquefaction, and export of gas at the LNG plant at Blang Lancang, near Lho Seumawe (Sumatra) Indonesia.

Mobil Oil Indonesia, Inc. is the field operator and P.T. Arum NGL Company operates the pipelines and LNG plant facilities. All the facilities which will be described are owned by Pertamina; P.T. Arun is owned by Pertamina, Mobil Oil Indonesia, and Japan Indonesia LNG company (JILCO). JILCO represents the five (5) original Japanese LNG purchasers.
A Reservoir Optimization Study—El Bunduq Field, Abu Dhabi, Qatar
Authors: Bashbush J. L. , Savage W. K. , Nagai R. B. , Ogimoto Tadao , Wakamiya Jun , Takizawa Hiroo
Published: December 2007

El Bunduq reservoir is located in the offshore area of Abu Dhabi and Qatar. The field was shut-in in July 1979 due to production with high gas-oil ratios. Pressure differences of 200-400 psi between the flanks and the central part of the reservoir were still present almost four years after the field was shut-in. A comprehensive reservoir engineering study determined that the reasons for this behavior were the deteriorating qualities of the reservoir rock downstructure and the presence of a tar mat around the field.

After the field behavior was history matched, model studies of a representative sector of the field indicated that peripheral waterflooding would recover less than 15 percent of the 00IP in a period of 30 years. However, pattern injection recoveries were calculated to be at least twice as high. Several full field alternatives were investigated to optimize the development of the reservoir under a pattern waterflood. This paper summarizes the various studies that led to the acceptance of the idea of pattern development over peripheral injection, as a result of the unique characteristics of this field.