bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simple Analytical Model for Simulating Heavy Oil Recovery by Cyclic Steam in Pressure-Depleted Reservoirs
Authors: Gontijo J. E. , Aziz K.
Published: December 2007

The cyclic injection of steam to stimulate or produce wells in heavy oil reservoirs is extensively employed by the oil industry. The performance of such wells may be predicted from empirical correlations, simple analytical models or thermal reservoir simulators. Empirical correlations can be extremely useful for correlating data within a field and for predicting performance of new wells in that and similar fields. However, use of such correlations for situations much different from the ones that led to their development can be subject to large errors. On the other hand one can use a compositional thermal model to predict the performance of cyclic steam operations. While thermal models are based on the fundamental laws of conservations, the fluid flow is related to pressure gradient through the empirical concept of relative permeability. In addition, the inherent sophistication of a thermal model makes it sensitive to rock properties, fluid properties and geological features. Much of this information is often unknown and must be estimated from limited data and experience in similar situations. Furthermore, because of the complexity of the recovery process - which involves reversal of flow directions - the equations of a thermal simulator are difficult and expensive to solve. All of this means that the use of a sophisticated thermal model may not be appropriate for routine design of cyclic steam operations. Instead one must consider the development and use of simple analytical models which give due consideration to important mechanisms involved in the process.

In this study existing analytical models for cyclic steam are reviewed and a new model is proposed. This model incorporates many of the features of existing models with some important refinements. The flow rate of oil in the model is influenced by oil viscosity, effective permeability of the heated zone, porosity, mobile oil saturation and thermal diffusivity of the reservoir. The change in reservoir temperature with time is also modelled, and it results in the expected decline in oil production rate during the cycle. The model accounts for the heat remaining in the reservoir from previous cycles. The model equations are kept as simple as possible and, wherever appropriate, correlations are incorporated to minimize data requirements.

The results of the model compare well with available field data and another analytical model. The model results are also compared with a thermal simulator.
"Service and Supply"
Authors: Cruikshank T. H.
Published: December 2007

Ladies and gentlemen, I am honored to be here today. My topic is "Surplus and Shortages in the Service and Supply Industry" --and, in a broader sense, the outlook for the industry,

Let me say at the outset that the outlook is better now than it has been. But before anyone gets too excited, we must remember that from our industry's viewpoint it would be difficult for the situation to get cny worse than it was. Nor can we be certain that "better" will be enough to eliminate our problems in the short term. For the longer term, though, I believe there are brighter times ahead.

What is really brought home in analyzing where we were, where we are, and where we are going is the clear message that the old, predictable economic rules of supply and demand are functioning freely in our market place, And I don't believe we can escape them, Certainly, we in the service and supply industry enjoy it a lot more when demand is rising and our main problem is how to increase supply. However, it is also apparent that the pendulum sometimes swings too far before the corrective mechanism begins to work, Then the adjustment is painful and costly, That has been our experience in recent times.
Conclusions Based on Laboratory Tests of Tubing and Casing Connections
Authors: Biegler K. K.
Published: December 2007

In the last two years, many of the available tubing and casing connections have been evaluated at the Exxon test facility. While we have not tested every available connection on the market, these tests have covered a range of connection types which incorporate the most commonly utilized connection design features. These features include various thread forms and configurations and also independent seal designs and seal combinations. In all cases, testing showed behavior that either differed from the manufacturer's published claims or varied from the behavior predicted by generally accepted mathematical models. The behaviors this paper will discuss include stress magnitudes and distributions, leak resistance under combined loads, and individual pressure and tension capabilities. Conclusions based on this test data will be presented for each design feature tested. Also included in the discussion are overviews of the new technology in connection designs which have evolved, in the most part, from attempts to solve the problems brought out in the existing test data. While most of these problems have not led to catastrophic failures in the field or laboratory, they have pointed out the need for better connection performance models and laboratory verification of these models.
Predicting Makeup Torque of Threaded Tapered Connections and Evaluation of Coefficients of Friction
Authors: Hawke Melvin C.
Published: December 2007

This paper will show how it is possible to generate a general purpose formula to determine the amount of torque required to make up non-shouldering tapered threaded connections as are commonly used on tubing and casing connections. In addition, by manipulating this algorithm, values for the dynamic coefficient of friction of thread compounds may be derived. This algorithm allows any type of thread form to be analyzed and was verified through actual testing.
Threaded Connector Evaluation for Heavy-Wall Production Tubing in a Deep Well
Authors: Payne M. L. , Galate J. W. , Allen M. B. , Hurst D. M.
Published: December 2007

In order to qualify a connector for a deep, critical service gas well, a connector evaluation program was executed which included both destructive laboratory testing and computer analysis. The advantage of using both tests and analysis to evaluate connector performance is emphasized. Both tests and analysis have strengths and limitations that must be understood and properly manipulated to construct an optimum evaluation program.
3D Thermal Simulation Using a Horizontal Wellbore for Steamflooding
Authors: Rial R. M.
Published: December 2007

Steamflooding has been used for years in enhanced oil recovery. However, the use of a horizontal wellbore for injection is a relatively new application that could improve process efficiency. This paper explores the effect of a horizontal wellbore for steamflooding using a three-dimension thermal simulator. Using a Primos 1, and lately a Cray-1, a comparison was made between a conventional vertical wellbore and a horizontal wellbore model.

The data used were representative of the Kern River Field, Kern County, California. The results of the two models showed a 13% increase in oil recovery for a horizontal wellbore. The temperature and oil phase saturation distribution revealed an improved sweep efficiency with a horizontal wellbore. For a five year period the horizontal model had production of 214.14 MSTB (64% OOIP) compared to 163.61 MSTB (51% OOIP) for the vertical model. After 15 years the horizontal model produced 237.55 MSTB (71% OOIP) and the vertical model produced 194.01 MSTB (58% OOIP). The heat transmissibility was higher throughout the grid system using the horizontal model.

A horizontal wellbore proved to enhance oil recovery for steamflooding using the data and simulation developed. There are also possible applications to other enhance oil recovery processes.
Cased-Hole Evaluation with the Chlorine Log
Authors: Deimel J. M. , Andrus D. G.
Published: December 2007

Typical problems faced by operators in the Gulf of Mexico are the evaluation of low resistive potentially productive zones and depleted zones behind pipe. Tenneco Oil Company has used the chlorine logging system to solve these problems in numerous wells and several case studies are presented.

The chlorine logging system is a neutron-capture spectral measurement and analysis technique which provides a quantitative, 1ithology-independent water saturation (Sw) interpretation. Water saturation is derived from the measured spectral response, formation porosity, formation water salinity, and well bore geometry. No corrections for borehole fluid or shale volume are necessary. This logging system demonstrates its usefulness in evaluating low resistivity pay zones and evaluating water movement within producing and/or produced zones.
A Fast Coupling for a Deepwater Drilling Riser
Authors: Le Peuvedic J. P. , Guesnon J. , Soleille L. M.
Published: December 2007

ELF AQUITAINE and TOTAL have operated the D.P. drill ship Discoverer Seven Seas in the Mediterranean Sea, temporarily establishing a new world water depth record on GLP1 well located south of Marseilles in 5 624 ft of water.

The success of this well and the following well GLP2 in the same area can be partially attributed to the careful engineering devoted to the riser system in cooperation with Institut Francais du Pétrole (I.F.P.). This riser built by CREUSOT-LOIRE uses a new connector allowing fast make-up and disassembly resulting in considerable time saving and increased safety for deep water operations.

Unlike all the other riser couplings, the CREUSOT-LOIRE/I.F.P. connector has no prestressed members. The load is entirely carried through compressive stresses at the interface. This eliminates the requirement to preload by tightening six or more bolts. Therefore the connector closing time is drastically reduced and the assembly of the riser is speeded up and nearly three times faster than conventional preloaded types.
Modified McKinley Early-Time Well-Test Analysis for Very Large Reservoirs: An Application to Prudhoe Bay
Authors: Petersen E. J. , McNaughton D. A. , Economides M. J.
Published: December 2007

Pressure buildup tests from wells of a very large reservoir are analyzed using McKinley Early Time Analysis as extended by Streltsova-Adams and McKinley (1982) to account for partial completion. Other recent papers which address the issue of partial completion are briefly summarized also. Because the wells are directionally-drilled and partially-completed, a configuration pseudo-skin equivalent is determined for each well using correlations developed by Cinco-Ley, Ramey and Miller (1975). This quantity, which is a function of completion ratio and location, hole angle, and dimensionless formation thickness, corresponds to a Streltsova-Adams and McKinley (1932) partial completion factor. The configuration pseudo-skin equivalent varies from zero to one and is used for type curve selection in the same manner as the partial completion factor.

This work presents a procedure for the determination and application of the configuration pseudo-skin equivalent and demonstrates its use in early time analysis. Data from twelve pressure buildup tests on five Prudhoe Bay wells are analyzed and the results are presented with a discussion. It is shown that by accounting for all pseudo-skin effects due to well configuration, McKinley Early Time Analysis can be generally applied to yield consistent and reliable results, allowing valuable information to be obtained from conventionally uninterpretable pressure buildup tests.
MWD: Formation Evaluation Case Histories in the Gulf of Mexico
Authors: Hendricks W. E. , Coope D. F. , Yearsley E. N.
Published: December 2007

Measurement-While-Drilling (MWD) logs are being used in the Gulf of Mexico for formation evaluation as well as for drilling applications in both exploratory and development operations. This study presents six case histories involving MWD data. They have been selected to illustrate various applications and some special features of MWD logs. Excellent well-to-well correlations with offset wireline logs as well as reservoir fluid movements in producing fields have been observed. Troublesome wells that could not be logged with conventional wireline techniques have been successfully logged with MWD tools. MWD resistivity data have been used to infer formation pore pressures. The quantitative accuracy of MWD logs is demonstrated by comparison with wireline induction logs recorded in the same wells.
The Effect of Bit Hydraulics on Bit Performance in Relation to the Rock Destruction Mechanism at Depth
Authors: Feenstra R. , Zijsling D. H.
Published: December 2007

Bit hydraulics can contribute to a bit's performance by one or more of the following actions: *reduction of chip holddown*jet cutting*reduction of bottom balling*reduction of bit balling*transport of cuttings towards the annulus.

How and to what extent bit hydraulics can help to improve bit performance is mainly determined by the bit's cutters (teeth, inserts, diamonds, PDCs, jets), the drilling fluid and the formation drilled under downhole conditions. The introduction of a self-cleaning bit strainer and self-cleaning bit cutters widens the scope of bit hydraulics, particularly for PDC-type bits.
Planning and Practical Problem Solving Using an Engineering Simulator for Drilling
Authors: Brett J. F. , Summers M. A.
Published: December 2007

This paper contains examples and case studies showing how a detailed drilling simulator can be used as a tool to help make decisions concerning bit selection, proper hydraulics, solids control, mud system selection, and the development of a comprehensive well plan. These studies demonstrate the value of the simulation process and how it can be used to weigh the options facing an operator and determine their effect on the final well cost.

The example results indicate not only that the simulator is capable of modeling the drilling process accurately and in great detail, but that each alternative that is simulated can have a cost calculated for it so it can be compared against the other options. This ability to evaluate different options is shown to be an integral part of the well planning procedure. The use of the simulator can help develop and improve comprehensive drilling plans more quickly than the use of conventional analysis. This allows faster learning and cost savings in actual field operations.
An Unusual Case of Salt Plugging in a High-Pressure Sour Gas Well
Authors: Place M. C. , Smith J. T.
Published: December 2007

During the course of development of the deep Mississippi Smackover trend Shell encountered a particularly troublesome production problem in one well, the Shell Ridgway 1-R well in the Southwest Pineywoods Field. This well plugs after producing approximately 1 BCF of gas and must be treated on a regular basis by injecting fresh water to restore the productivity of the well. Eight other Shell wells in three fields in the deep Mississippi Smackover trend have produced without encountering this problem. We have concluded that the plugging observed in the Shell Ridgway 1-R well is caused by the deposition of NaCl in the well bore. We believe that a trace of brine (±0.05 bbl/MMCF) is produced from an anomalously high water saturation interval in this well. This high water saturation interval is located ±300 ft. above the gas water contact in the field. Other zones having low water saturations were penetrated at greater depths in the well. We believe that this unexpected production of a small amount of brine from an isolated interval within the pay section possibly combined with the nature of the well completion created the plugging problem.

Initially we did not consider that brine flow could occur in a well completed ±300 ft. above the gas water contact. Instead we thought that transport of NaCl in the high pressure sour gas might be responsible for the plugging. To evaluate this possibility we supported a program conducted by Dr. James B. Hyne of the University of Calgary to measure the solubility of salt at reservoir conditions in the sour gas. His measurements show that trace amounts of NaCl are carried in the high pressure sour gas. However, we were not able to use Hyne's results to explain the difference between the production characteristics of the Shell Ridgway #1-R well and the other wells in the trend. Hyne's results do raise a warning that under certain conditions plugging due to NaCl deposition in the reservoir may occur in high pressure sour gas wells. Tn this paper we shall develop our understanding of this plugging problem by presenting material on two wells: the Shell Ridgway 1-R well in the Southwest Pineywoods Field, and the Shell Burch #1 well in the Thomasville Field. These two wells have pay zones of similar quality and are located in similar positions relative to the gas water contacts in their respective fields. The following items will be discussed:

Characteristics of the pay intervals, reservoir conditions and structural settings for the two wells. Completion and production histories for the two wells. The solubility of NaCl in sour gas based on the work of Dr. Hyne and the implications of these data for the plugging problems. Chemical evidence to support the hypothesis that NaCl deposition occurs from brine flowing into the Shell Ridgway 1-R well. A suggested prognosis of the sequence of events during a plugging and treatment cycle of the Shell Ridgway 1-R well.
Rod Pumping Optimization Program Reduces Equipment Failures and Operating Costs
Authors: Allen L. F. , Svinos J. G.
Published: December 2007

In 1975, an intensive program was initiated by Gulf Oil E&P Central Area to reduce rod and tubing failure rates in the fields of the northwest corner of Crane County, Texas. Chronologically the program steps were: 1) The replacement of rod strings experiencing three failures in three months. 2) The replacement of tubing strings experiencing two failures in three months. 3) The use of inspected, classified and plastic coated new or used grade "C" rods. 4) The use of inspected, classified and internally plastic coated used or new tubing. 5) The exclusive use of high working stress rods. 6) The exclusive use of specially designed fiberglass sucker rod systems with improved sinker bar design.

This program reduced rod failure rates from 16% to 4% and tubing failures from 7% to 3% per month. The lighter rod design reduced lifting costs by $2 MM per year on 880 active wells. Of the 219 wells equipped with fiberglass sucker rods in the last two years, there have been no operational body breaks or tubing leaks.
Vertical Single-Well Pulse Testing of a Three-Layer Stratified Reservoir
Authors: Lee S. T. , Chien M. C. H. , Culham W. E.
Published: December 2007

A new mathematical model is developed for analyzing single-well pulse test data from a reservoir consisting of two permeable zones separated by a less permeable zone. The model considers well-bore storage and skin effects and allows the three zones to have different rock properties. The line-source assumption used in developing the analytic solution is validated via comparison of results with another model also developed in this work. This latter model assumes identical rock properties for the two permeable zones but allows the wellbore radius to be finite.

The numerical Laplace inversion methods available in the literature are evaluated with respect to some simple functions and the analytic Laplace space solution of the problem of interest. It is found that the Fourier-series and Zakian's methods can serve as alternatives to the well-known Stehfest algorithm.

The effects of wellbore storage and skin on single-well pulse testing of layered reservoirs are investigated. Consistent with the findings in the literature for multiwell pulse testing, it is shown that the influence of wellbore storage and skin is to reduce the response amplitude and to increase the time lag of the pulse response. Among the wellbore storage and skin factors involved in a single well pulse testing, the skin associated with the observation interval is least influential on the pressure response.

Using field data, it is shown that the mathematical model presented can be used, in conjunction with an optimization subroutine, to estimated the parameters of interests. It is further shown numerically that neglecting the effects of wellbore storage and skin could result in an underestimation of the formation permeabilities of interest. The problem of non-uniqueness of solution for parameter estimation using optimization techniques is also discussed for the subject problem.
Experimental and Numerical Investigations of the Primary Depletion of a Critical Fluid
Authors: Alonso M. E. , Nectoux A. C.
Published: December 2007

The oil recovery expected from a fractured rich condensate gas reservoir is usually low. Most of the liquids remain trapped in the matrix porosity. However, when the amount of condensate is high, i.e. for a hyper-critical fluid, a simple natural depletion could lead to very high recovery levels, especially when the reservoir is heavily fractured. The object of this study was to understand physically and numerically the compositional flow mechanics which take place inside the fracture-matrix reservoir rocks. From the results it appears that high recovery levels could be also foreseen for natural depletion of volatile oil reservoirs.
Eastern Gas Data System: An Interactive Industry Resource
Authors: DeVos D. R. , Skrinak V. M. , Hoffmann R. L.
Published: December 2007

The Gas Research Institute (GRI) Eastern Gas Data System (EGDS) is an interactive information resource developed to provide ready access to substantive data on wells producing from the Devonian shales. The system is a computerized database which contains descriptive and historical geologic and engineering data on a large number of Devonian shale gas wells in the Appalachian Basin. The principal purpose of the system is to meet the technical data requirements of gas producers, researchers and GRI. The data are provided by cooperating industry sources, many of whom were also instrumental in the original definition and design of the system. The information which is being collected and compiled on individual wells includes data on identification, location, elevation, drilling, geology, cementing, perforation, stimulation, cleanup, and production histories. Several personal computer (PC) based enhancements to support statistical and economic analyses using this data are currently under development. The Eastern Gas Data System currently contains extensive information on over 620 Devonian shale gas wells completed in the Appalachian Basin. More than 300 additional wells will be included in the system by the end of 1984.
A Systematic Evaluation for Future Developments of Gas-Bearing Formations in West Virginia
Authors: Salamy S. P. , Ameri S. , Aminian K. , Yost A. , Komar C.
Published: December 2007

The objective of this paper is to evaluate and identify areas/counties with the highest potential for future development of gas bearing formations in West Virginia. The results will provide sources of regional comparison as well as a guide for future leasing.

The gas bearing formations under study consist of, but are not limited to, Big Injun, Berea, and Benson horizons. The reservoir parameters/data pertaining to the mentioned formations have been collected over the past twelve months. The qualitative and quantitative interpretations of data and assessment of various areas/counties for future development are enhanced by computer generated 2-dimensional and 3-dimensional maps. The generated maps are the quantitative representation of various reservoir parameters such as porosity, gas saturation, open flow potential, pay zone thickness, etc., as a function of latitude and longitude. The superimposition of the mentioned 3-dimensional maps (of different reservoir parameters) provide the basis for ranking the potentially productive areas/counties in West Virginia. Meanwhile, the 2-dimensional maps are utilized to indicate the precise locations within the county/area of interest.

The characterization of the above mentioned horizons that are stratigraphically located above the Devonian Shale will enhance the attractiveness of further exploration/development of shale reservoirs through comingle production and/or dual completion in areas of highest potential as specified by 3-dimensional maps.
Dynamometer Testing on Pumping Wells: Field Applications in the Appalachian Basin
Authors: Rdissi A.
Published: December 2007

Although dynamometer testing has been common for many years, its use in the Appalachian Basin has been very limited. This paper presents the procedure and the techniques to conduct the test and interpret the valuable information that can be obtained. Several field examples depicting different problems will be presented and solutions offered to solve them and prevent future ones from happening. The paper will also show, through actual examples, that many common practice procedures employed today to produce pumping wells are not very sound and that a dynamometer test can reveal baluable information about the pumpine equipment and downhole apparatus, which otherwise could not be detected. The final outcome will be lower operating costs and more savings since the workover frequency rate on pumping wells will be significantly reduced.
Heated Acid for Improved Stimulation Results
Authors: Walker M. L. , Fredrickson S. E. , Norman L. R.
Published: December 2007

A simple and practical process has been developed to heat hydrochloric acid to improve its performance as an oil well stimulating agent. Heated acid is used in cold formations, such as cold dolomites, to increase the rate at which the formation is dissolved, thus improving flow capacities. The new technique heats the acid by causing an exothermic chemical reaction that uses a portion of the HCl as one of the reactants.

Heated acid reacts at a faster rate and aids in removal of acid-retarding materials such as oil, asphaltene and paraffins from the formation to give a better acid-to-formation contact. Some other benefits of heating acid are:

Helps prevent precipitation of organic materials from oils that have been cooled by acids. Limits the amount of tubing contraction due to temperature change.

Problems presented by the slow reaction time of HCl in cold formations and the special problems of conducting winter time acid treatments are largely solved by heating HCl up to bottom hole temperature or more prior to pumping. This paper presents laboratory and field results to illustrate the effectiveness of the heated acid method of stimulation and compares the various methods of bringing the acid to its ideal temperature.
Tubing-Conveyed Perforating With Hydraulic Set Packers and a New High-Pressure Retrievable Hydraulic Packer
Authors: Hailey T. T. , Donovan J. F.
Published: December 2007

The oil industry has recently begun using tubing conveyed perforating (TCP) guns with much greater frequency than in the past. The advantages of larger explosives, higher shot density, unlimited gun length, and removal or reduction of formation damage by perforating with a pressure differential into the wellbore have caused the number of wells perforated with TCP guns to increase at a time when the number of wells perforated industry-wide has drastically decreased.

Although these advantages are becoming well known, a superior well completion design and procedure making use of hydraulic set packers in conjunction with TCP guns has not yet been "discovered" by the oil and gas industry except for a few isolated applications. This paper outlines the various capabilities and options made possible in completions using hydraulic packers and TCP guns, including wellhead installation before perforating, circulation capability until just before perforating, and "floating" seal designs. Various completion designs for differing situations of pressure, temperature, and corrosion are presented.

A limiting factor in the use of TCP guns in high pressure completions has been the high cost of gun failure caused by the lack of availability of a retrievable hydraulic packer capable of differential pressures above about 6,000 psi (41.4 MPa). The recent development of such a packer, with demonstrated differential pressure rating of 12,000 psi (82.7 MPa) and temperature rating of 450°F (232°C), makes many high pressure, high cost completions likely candidates for the TCP gun-hydraulic packer completion design. This paper includes a case history of such a completion. The discussion describes the types of hydraulic packers used with TCP guns and the seal systems associated with each, the types of firing systems used, and gives two typical completion procedures; one the case history just referred to, and one, a case history of a low pressure completion.
Supplier/Services Relationship—Gains and Losses, 1982 to 1984
Authors: Schneider R. J.
Published: December 2007

During the drastic boom-bust turnaround between 1979 and 1983 the service and supply part of the industry – along with the drilling and production sectors – provided too much capacity. We were caught with too much inventory. Much of the capacity and inventory was purchased with borrowed funds at high interest rates. When activity dropped, we had to bite the bullet and cut our costs. Prices became soft and discounting became a detrimental way of life. Bold steps have been taken to meet the current market.

It is mandatory that we know and understand the needs of the industry so that we will provide the modern services and supplies needed in the future on a timely basis. It is also mandatory that our dealings be in a business like way with reasonable profits that will provide the funds necessary to meet those requirements. The service and supply sector is an important part of your industry and we are determined to "earn our stripes."
From Derrick to Desk: A Drilling Training Program
Authors: Davis N. , Simmons E. L.
Published: December 2007

In 1977, with the purchase of a National T-45 and a National T-55 drilling rig, and later three other rigs, Gulf Oil Corporation embarked on an ambitious—and unique—training program to provide company directed, hands-on training in three major areas: drilling engineering; drilling fluids technology; and drilling supervision. Gulf subsequently increased its technical training by offering a broad range of drilling schools under the Drilling Department at the Houston Technology Center (HTC), and implementing well control training at its New Orleans Training Center.

The present training program is patterned after an earlier, successful Gulf program, initiated in the 1940's, in which engineers would spend six months on a company rig, attend a mud and engineering school, serve several years as field mud engineers, and then continue in their career development as drilling engineers or drilling supervisors. Non-engineering personnel also received on-the-job training which served as a foundation for advancement to the drilling supervisory level. Based on changing company needs, in 1956 the rig program was phased out, until its reinstitution 21 years later, in 1977.

In 1983, the Drilling Department was charged with providing all training in areas of drilling operations. The Drilling Technology Center (DTC), a new facility dedicated to that program, was built with sufficient classroom and laboratory space and equipment to meet the industry's rapidly expanding technical training needs. The facility has a drilling rig for hands-on, well site training covering virtually all aspects of drilling, with a heavy emphasis on safety training. The program includes well control training, and has schools covering such subjects as stripping and snubbing, well completions, and directional drilling.

Gulf's integrated training program now provides drilling personnel with instruction throughout the individual's career development, from the first days on the derrick to later days, in management, behind a desk. This paper describes Gulf Drilling Department's total training program, both as contractor and operator in the oil industry.
Solids Control Design and Analysis Using an Engineering Simulator for Drilling
Authors: Skidmore D. B. , Anderson C. T.
Published: December 2007

Properly designing solids control systems for different drilling situations requires an analytical systems approach. Conventional methods for choosing, sizing and operating various solids control devices do not account for the interdependence of the solids control system with other systems such as the mud system, rig power distribution (SCR) system and the bit penetration system. The Engineering Simulator for Drilling (ESD) is a tool that does consider the entire drilling process and all of the interdependencies of the component systems.

This paper describes how the ESD can be used to analyse solids control systems considering the design, configuration and operation of the individual devices and the entire solids control system. The impact of good solids control on overall drilling efficiency, especially rate of penetration, is discussed. The user can design a solids control system and also measure the performance of each individual device and of the system as a whole. Direct comparisons can be made between the particle size distributions at the flowline and the mud pump suction as well as the inflow and outflow of any of the specific devices. Sophisticated solids control analytical models have been developed to allow the drilling engineer to fine tune the operation of a particular solids control device and the entire mud tank system.

A case history is presented demonstrating the use of the ESD for analysing an actual field case. A well is analysed using the ESD, an improved plan and system is developed, and a simulated well is drilled using the new system.
Treatment of Drilling Fluid Wastes in an Environmentally Acceptable Manner
Authors: Wally B. F. , Reitsema L. A. , Nance G. W.
Published: December 2007

Drilling fluid wastes derived from the drilling process presents a unique disposal challenge to the drilling industry. New technology allows the environmental treatment and subsequent disposal of these wastes lessening the liability and costs to the operator.

Through chemical and mechanical treatment the disposal material is separated into the basic components water and solids.
Meeting Regulatory Agency Requirements for Electrical/Electronic Instrumentation Installed in Hazardous Locations
Authors: Stilwell S. A.
Published: December 2007

This paper is directed to the offshore drilling industry which is now using electronic instruments and systems in classified (hazardous) locations more than ever before. Much of the information, however, is applicable to onshore drilling.

National and international requirements, codes and regulations pertaining to the use of electrical/electronic systems and instrumentation in hazardous locations on offshore drilling units are outlined and discussed.

The agencies and regulatory bodies included are the United States Coast Guard, Minerals Management Service, the Canadian Coast Guard, American Bureau of Shipping, Lloyds Registry, the United Kingdom Department of Energy, Norwegian Maritime Directorate and Det Norske Veritas.

The paper discusses the applicable standards, approvals and certifications required and/or accepted by these agencies. The types of protection for electrical equipment (eg. intrinsic safety, explosion-proof, pressurization, increased safety, etc.) and their acceptance are itemized. Simularities and differences in acceptance are highlighted.

Information and suggestions are offered on how the regulations can be met in an efficient and cost effective manner. This applies to both electrical instrumentation installed on the drilling unit in the construction phase and instrumentation added after the drilling unit is in operation.
Drilling Representative Work Station
Authors: Mohney M. E. , Combes J. F. , Miller R. L.
Published: December 2007

Chevron is developing a rig-site microcomputer-based drilling representative work station (DRWS). The objective of the DRWS project is to integrate microcomputer technology with drilling operations by providing the drilling representative with three major functions. Real-time drilling parameters are captured from a rig monitoring system and processed. Engineering software is provided which aids the drilling representative in optimizing daily drilling operations. The DRWS also provides a highly interactive and versatile tool for rig site training of drilling personnel.
Inexact Adaptive Newton Methods
Authors: Bertiger W. I. , Kelsey F. J.
Published: December 2007

The Inexact Adaptive Newton method (IAN) is a modification of the Adaptive Implicit Method1 (AIM) with improved Newton convergence. Both methods simplify the Jacobian at each time step by zeroing coefficients in regions where saturations are changing slowly. The methods differ in how the diagonal block terms are treated.

On test problems with up to 3,000 cells, IAN consistently saves approximately 30% of the CPU time when compared to the fully implicit method. AIM shows similar savings on some problems, but takes as much CPU time as fully implicit on other test problems due to poor Newton convergence.
Minimization of Gibbs Free Energy in Compositional Reservoir Simulation.
Authors: Trangenstein J. A.
Published: December 2007

This paper describes the formulation of vapor-liquid phase equilibrium as a linearly constrained minimization problem. It also describes a second minimization problem designed to test for local phase stability. Vectorized unconstrained minimization techniques can be used to solve this pair of constrained minimization problems. The methods of this paper are applied to liquid-vapor equilibria for mixtures both far from and near to the phase boundary. Significant improvements over the standard successive substitution algorithm are demonstrated.
Unconventional Modelling of Faulted Reservoirs: A Case Study
Authors: Goldthorpe W. H. , Chow Y. S.
Published: December 2007

An example is presented of detailed unconventional gridding of the North Rankin Field, which is a large, structurally complex gas-condensate field offshore Western Australia. A non-Cartesian areal grid was used with corner point geometry to approximate a generalised curvilinear coordinate system for the surface and interior of each reservoir unit. Coordinate lines in the vertical plane at any node in the grid were tilted where necessary to define sloping edges and sides of grid blocks. Thus, any sloping twisted surface could be modelled.

To investigate possible communication across faults between different geological units, transmissibilities at faults were automatically calculated for any over-lapping cells and sensitivities made of the effect of varying these transmissibilities on well production, recovery factors, pressure decline and water encroachment. The model was solved with a fully implicit simulator using a Newton-Raphson iteration method for the non-linear equations and a variant of the Conjugate Gradient procedure with a preconditioning matrix for the linear equations.
Cyclic Steam Injection: Interpretation of Some Results from a Field Fluids Analysis Program
Authors: Bojes J. M. , Bulkowski P. B.
Published: December 2007

Cyclic steam injection has found wide application in the recovery of bitumen from heavy oil reservoirs. Once-through steam generators are commonly used and produce a high pH, low ionic strength effluent which has been shown to cause clay swelling and dispersion, as well as solubilization of silica and other minerals. To provide a better, more quantitative understanding of the effects of 80% wellhead quality steam on the formation, an extensive field fluids data base was established through frequent monitoring of the composition and changes in composition of injected and produced fluids at one of Petro-Canada's pilot projects. This paper highlights some of the interesting observations which resulted from this study regarding silica dissolution due to steam injection and silica levels in the produced water as well as the effect of the 3% KCl workover fluids on the ion concentrations in the produced water.
Profile Modification and Water Control With Silica Gel-Based Systems
Authors: Krumrine P. H. , Boyce S. D.
Published: December 2007

A major problem in maximizing oil production potential is the maintenance of adequate mobility control and favorable permeability profiles within the reservoir. Currently, polymer systems are receiving a great deal of attention in this application, not only as viscosifying agents, but also as cross-linked/gelled water blocking agents. Traditionally, silica gel systems had been used for such purposes. They still offer advantages in situations where polymer systems are limited by degradation and syneresis or are inadequate to shut off major thief zones.

This paper presents the chemistry of silica polymer gel systems, and reviews their properties, benefits, limitations, and methods of application. The properties such as gel time, strength, and shrinkage vary considerably versus the concentrations of reactants, the type of acidifying/gelling agent used, or the particular reservoir environmental conditions such as temperature, salinity, hardness, and hydrocarbon saturation. Gels ranging from elastic to rigid can be made with set times varying from a few seconds to several hours. Inorganic acids and reactants such as CaCl2 or NaAlO2 tend to react quite rapidly. Organic reactants that slowly hydrolyze or oxidize give more gradual formation of gels. Most reservoirs that contain high salinity, hardness, or temperature environments tend to accelerate the gel formation.

Examples of these effects are presented for several silicate based systems. Also the gelation of silicate in the presence of organic chemicals is discussed. Information from the grouting literature is reviewed so that a complete picture can be presented on the use and application of silicate based water control and production methods.
Permeability Modification Using Aluminum Citrate/Polymer Treatments: Mechanisms of Permeability Reduction in Sandpacks
Authors: Ghazali H. A. , Willhite G. P.
Published: December 2007

Permeability modification is used to improve volumetric sweep efficiency of fluid injection processes. The combination process, introduced by Needham, et al.1 in 1974, was envisioned to have unique properties. They reported that treatment of porous media with alternate slugs of polymer and aluminum citrate solutions led to a decrease in permeability which was resistant to degradation after many pore volumes of fluid injection. Large permeability reductions were obtained using polymer concentrations as low as 250 ppm.

This paper describes a study of permeability modification in sandpacks prepared from Ottawa sand using the aluminum citrate process which was undertaken to identify mechanisms causing permeability reduction and to improve process performance. Sandpacks with permeabilities between 1.73 and 2.92 darcies were used to eliminate the effects of clays on the process as well as rock heterogeneities. In the study, sandpacks saturated with brine were treated with alternate slugs of polymer, brine and aluminum citrate. Water Cut 160 and Water Cut 110 were the principal polymers used.

Experimental results indicate that little permeability reduction occurred when a brine slug separated the aluminum citrate and polymer treatments up to nine treatment cycles. Exclusion of the brine slug between aluminum citrate and polymer slugs in subsequent treatment cycles caused an abrupt reduction in permeability throughout the entire sandpack. Permeability was too low to be measured. Inspection of one sandpack after plugging occurred revealed the presence of a colorless, clear gell which adhered to the surface of the sand grains. Since similar gels were prepared at selected polymer and aluminum citrate concentrations in bottle tests, the permeability reduction mechanism appears to be in-situ gelation of Water Cut 110 by aluminum ion. This mechanism is quite different from the layered, aluminum/polymer network described by Needham, et al.1 and Thomas2.

Retention of polymer and aluminum was increased by an order of magnitude by cyclic treatment. However, retained polymer caused a small, if any, change in permeability prior to abrupt plugging of the sandpack. Retention of both polymer and aluminum involve processes which are rate dependent and are not understood.
Modeling of the Dissociation of an In-Situ Hydrate
Authors: Selim M. S. , Sloan E. D.
Published: December 2007

A mathematical model for hydrate dissociation has been developed. The model assumes dissociation of a pure hydrate using a constant heat flux incident on a planar semi-infinite medium with constant physical properties. The water formed during dissociation is assumed to be blown away by the gas so that the dissociation process may be regarded as a moving-boundary ablation problem. The governing differential equations describing the rate of dissociation are presented and solution is obtained using the Von-Karman integral method. Results from this solution are presented in graphs which can be used to estimate the amount of hydrate dissociated as a function of time.
Conversion of Mature Steamfloods to Low-Quality Steam and/or Hot-Water Injection Projects
Authors: Ault J. W. , Johnson W. M. , Kamilos G. N.
Published: December 2007

Three of Chevron's successful Kern River Field Steam Drive Projects (Section 3, Monte Cristo II, and American Naphtha) have been converted to either hot waterfloods or low quality (10%) steam injection projects. The projects' net oil production has increased significantly because of the reduced oil consumption at the steam generators. In general, the conversion to low quality steam or hot water injection has improved the oil production response of each project.

Production and reservoir data suggest that improved sweep efficiency in the lower part of the steam driven sands occurred as a result of the switch from high steam quality injection to reduced steam quality. This paper discusses the performance of these three projects. Production and reservoir parameters are identified which can be used to determine the timing for conversion of a mature steamflood to a lower quality steam injection project.
Using Numerical Simulation To Determine the Optimum Completion Interval for Steam Stimulation Wells, Section 34, North Midway Field, Kern County, CA
Authors: Brinker S. D.
Published: December 2007

The production of fluids from a heavy oil reservoir results in a "desaturated" zone of compressible gasses at the top of the formation. This zone can act as a steam thief zone during steam stimulation. A computer simulation study was made to determine if having a smaller interval open in a well could prevent the loss of steam to the desaturated zone and increase production. The study showed that with very thick formations (>250 feet), the optimum production was obtained with 74-55 percent of the net interval completed. For thinner sands (<250 feet), optimum production was obtained by completing as much of the net zone as possible.
Two Successful Steam/Foam Field Tests, Sections 15A and 26C, Midway-Sunset Field
Authors: Ploeg J. F. , Duerksen J. H.
Published: December 2007

Two successful steam-diverting field tests were conducted at the Midway-Sunset Field in the San Joaquin Valley, California. A Chevron proprietary sulfonate was used as a steam-diverting agent to improve oil recovery. The results showed that, for the conditions of the field experiment, the sulfonate used is very economic, significantly increasing oil recovery. Also, there were no associated sulfonate-handling and produced oil-treating problems.