bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the Inelastic Parameters of Geologic Materials from Incremental Creep Experiments
Authors: Hardy Reginald H.
Published: December 2007

Introduction

In spite of the increased research on the behavior of geologic materials which has been undertaken in recent years, many of the most important mechanical properties have not been investigated in detail. In particular the effect of time has received very little attention from the experimental point of view, although its importance has been suggested by many workers. Many workers have reported that test results appeared to be influenced by the rate and duration of loading, although few have been willing to accept the fact that such behavior is indicative of an inelastic material.

A general study of the Mechanical properties of geologic materials was initiated in 1951 in The Mining Research Section of the Fuels and Mining Practice Division, Mines Branch, Canadian Dept. of Energy, Mines and Resources, as part of a fundamental study of ground stress in Canadian Coal Mines. initial work was restricted to short-period tests on typical mine rock under uniaxial compressive stress, but as the importance of the "time factor" became more obvious, studies were undertaken to investigate time-dependent behavior. These studies, which were initiated in 1957, consisted mainly of a comprehensive literature search on the subject, and the initial development of experimental facilities. This research project was inactive during the period 1959–1961 due in part to the relocation of laboratory facilities.

In the fall of 1961 the project was reactivated with the proposed research program being broadly outlined as follows:

"To study experimentally the mechanical behavior of selected geologic materials and to analyze these experimental data using the concept of Technical models and the analytical methods of viscoelasticity. In particular to develop governing equations for these materials based on suitable laboratory experiments and valid at least within a range of stress, confining pressure, duration of loading, and temperature consistent with practical applications."

The first phase of this research program included the experimental investigation of the inelastic behavior of a number of "simple" geologic materials using incremental creep experiments, and the associated development of the necessary experimental facilities and analytical methods. This paper outlines briefly the experimental and analytical techniques developed, and presents experimental results for the initial deformation studies carried out on Wombeyan marble.

THEORY

Papers dealing with the behavior of geologic materials are found to be widely dispersed throughout the literature. However, extensive bibliographies dealing with the general mechanical properties of these materials have been published recently by Griggs and Handin and Mitra and Willson. In the more specific field of time-dependent behavior of geologic materials extensive bibliographies have been given in papers by Hardy, Murrell and Misra, and Robertson.

P. 105^
A Unified Approach to the Solution of Reservoir Simulation Equations
Authors: Abou-Kassem J. H. , Farouq Ali S. M.
Published: December 2007

This paper develops a general method for solving reservoir simulation equations, which is based upon an implicit finite difference formulation of the partial differential equations of compositional thermal simulation, permitting the simulation of nearly all enhanced oil recovery techniques. The general method is used to derive 10 solution schemes, which include the well-known IMPES, Simultaneous Solution (SS), and Sequential Solution (SEQ) methods as sub-cases. The novelty of the general method lies in showing the interrelations of these methods, and also affording the possibility of deriving still other methods.

The theoretical development of the general method is given in detail, and the special methods are derived in reference to the reservoir problems for which they were employed. The starting point is a system of nonlinear finite difference equations, typical of compositional thermal simulation. Newtonian iteration then leads to a system of equations. The partitioning of the left-hand side (containing the unknown vector) in a particular manner permits the derivation of 10 solution approaches, which are identified in detail.

The proposed general method bridges the gap in the development of the reported solution methods, and also points to several new approaches. The procedure described can be utilized for a variety of simulation problems, with fully implicit source-sink terms (including heat loss, thermal cracking, etc.), for both the standard and multipoint difference schemes in multi dimensions.
Utilization of Gravity Drainage Holes in Shallow Oil Recovery by Mining: Part II—A Conceptual Model for Drainage Hole Recovery
Authors: LeBlanc J. L. , Ghalambor A. , Asadi M.
Published: December 2007

Oil production by gravity drainage is affected by many factors in addition to reservoir fluid and rock properties. When the production of oil is through a drainage hole system established by oil mining techniques, the force of gravity and the characterization of the drainage holes also provide the means for the recovery of oil. Characteristic parameters such as length, diameter, number of holes and inclination angle of the drainage holes can influence the gravity drainage mechanism. The intent of this paper is to present a conceptual mathematical study of this gravity drainage process, whereby the recovery of oil is through a system of drainage holes penetrating the oil bearing formation. Production from the reservoir occurs through a completion interval located at the base of the sand.

A simplified gravity drainage model was developed based on Darcy's Law expressed in terms of the flow potential change during gravity drainage. Conceptually, the model combines a mass flow rate balance with one-dimensional vertical drainage based on Darcy flow to formulate a new frontal velocity equation for the demarcator. The finite-difference model restrictively computes oil production rate and recovery performance for simulated drainage areas with unconventional drainage hole completions.

An intrinsic limitation of the model is its dependence on a known value of the equilibrium height for a given drainage hole configuration. The combined effects of capillary gradients, relative permeability and gravity head in the transitional zone are excluded in the model's formulation. When permeability is sufficiently high, this later assumption may be compensated for by utilization of capillary pressure data to obtain iterative values of displaceable porosity. Continued mathematical development should enable this model to evolve as a reliable predictive tool.
A New Wellhead Installation Technique
Authors: Talbot K. J. , Schmitz T.
Published: December 2007

A new wellhead installation technique has been developed and field tested. The new wellhead system employs a cold forging process which eliminates the need for welding the casing head to the initial casing string an operator sets. Advantages of the new system are its speed of installation, elimination of undesirable welding stresses, and the technique's insensitίvity to weather. Described in this paper are the features of the new wellhead installation technique and details surrounding the industry's first installation on a 13-3/8″ casing string in July of 1987 in the Gulf of Mexico. Also documented is a discussion of field and engineering data to test its metal to metal sealing characteristics.
Laboratory and Field Evaluations of Novel Inorganic Drilling Fluid Additive
Authors: Burba J. L. , Holman W. E. , Crabb C. R.
Published: December 2007

A novel inorganic compound has been developed that combines with dispersed bentonite producing a fluid which exhibits unusual shale inhibition, solids suspension, and contamination resistance. Laboratory and field test data are discussed.
Drillstring Identification to Reduce Drillstring Failures
Authors: Twilhaar G. D. Nijen , Hogen Esch J. H. L.
Published: December 2007

A novel system has been developed, which reduces the number of drillstring failures by enabling the accumulated fatigue load of each individual drillstring component to be recorded. A prototype is currently undergoing field tests. Labels incorporated in drillpipes are used to identify the components. Information on the accumulated fatigue load of each component can then be stored in the label. Besides labelling drillstring components, the labels have many other applications in the drilling industry.
Time and Cost Reductions Through a Database-Designed Directonal Drilling Program
Authors: Allison J. L. , Rezvani M. , Leake R. E.
Published: December 2007

The key to drilling a successful well, from a directional point of view, is having an organized program to follow beforehand. This program should foresee all possible problem areas and include all drilling parameters, Bottom Hole Assemblies (BHA) and individual tools. The tools alone will not drill the hole, but with the support of operators and office personnel as well as an organized and readily retrievable pool of information, time on bottom will increase while costs dec rease.

This combination of experienced personnel and computerized information constitutes what we refer to as "Know-How". Actual drilling data retrieved from a computerized database adds to the validity of a directional decision. The database aids in the planning and drilling of the well while reducing costs by eliminating uncertainty. Drilling technology has increased tremendously over the past five (5) years. Associated with this technological growth, unfortunately, comes an upswing in complexity that requires know-how for proper utilization. Improper utilization will reverse the trend of cost and result in higher expenses. By efficiently utilizing technology and preserving this knowledge in the form of a directional database, reproduction is only a page away.

This new concept allows educated decisions to be made long beforehand as well as concise immediate decision making. The program is designed to make hole. Staying on bottom, eliminating unnecessary trips and motor runs, reducing time and costs as well as hitting targets are all results of the concept. The system is an additional engineer with expertise in hydraulics, Bottom Hole Assembly (BHA) design, MWD's, mud motors, bits and conventional as well as advanced directional drilling techniques. The concept has been proven very effective throughout the Gulf of Mexico.
Mud Pump Liner Size and the SCR Rig
Authors: Schmidt G. J. , Broussard W. J.
Published: December 2007

Mud pump liner selection in today's drilling operations seldom (at best) considers electrical implications. Perhaps, with more available useful information about the relationships between mud pump liner size and operational effects on the electrical system, certain potential problems can be avoided. The intent of this paper is to develop those relationships and show how they affect an electrical system on example SCR rigs.
Lateral Drilling Technology Tested on UCG Project
Authors: Tracy P. B.
Published: December 2007

This case history describes state-of-the-art lateral drilling technology used to complete an underground system of process wells for a UCG project In central Wyoming. The Gas Research Institute and the U.S. Department of Energy funded the project. Eastman Christensen's medium-radius system was selected to drill the wells.

The Rocky Mountain 1 Underground Coal Gasification Project required that six wells, grouped into two parallel modules, be drilled into a 30-ft thick coal seam. Vertical depth for the wells was approximately 390 ft. Each module will be used to test a different coal burning process.

Key achievements of the drilling phase of the project include placing multiple lateral wellbores in the bottom 3 ft of a relatively thin coal seam located at shallow vertical depths; running and cementing 7-5/8 ln. casing In boreholes with curvatures of 20 deg/100 ft; and completing all lateral and vertical wells on-target and within stated tolerances.
The Navigation Drilling System Proves Effective in Drilling Horizontal Wells in the Java Sea
Authors: Barrett S. L. , Lyon R. G.
Published: December 2007

This paper describes the progress of the ATLANTIC RICHFIELD INDONESIA INC. horizontal drilling program. The program was initiated in the BIMA Field of the Java Sea for sixteen horizontal and high angle wells during 1986-1987. It was then extended to other development prospects in 1987. To date, eighteen horizontal wells have been drilled using standard rotary drilling techniques, standard mud motors with bent subs and the Navigation Drilling System. A total of 24,909 feet of horizontal hole has been drilled.

The wells were designed with the hole angle building to 86 degrees in the 12 1/4″ hole section and running intermediate 9 5/8″ casing. They were then maintained near horizontal in the 8 1/2″ hole through the relatively soft limestone pay section. Horizontal hole sections as long as 2351 feet were achieved.

The Navigation Drilling System consists of a positive displacement mud motor, a specially designed double tilted U-joint (DTU) and an MWD system. The use of the Navigation Drilling System became standard procedure to help overcome the unpredictable behavior of conventional drilling assemblies and to respond to changing lithology. The Navigation Drilling System substantially increased the confidence level for hitting small targets and drilling pre-described courses through the pay section. Targets as near as 830 feet horizontally from the surface location were achieved; and, long horizontal sections were repeatedly drilled successfully. To date, 7133 feet of horizontal hole has been drilled using the Navigation Drilling System.

Concurrent with the introduction of the Navigation Drilling System, drilling costs were steadily reduced while drilling accuracy steadily improved. Relatively inexpensive, lightly dispersed, polymer muds were utilized successfully over a wide range of hydraulic conditions. Hole cleaning, hole stability, torque and drag were never a problem.
A Stress-Controlled Drag-Reduction Phenomenon
Authors: Savins J.G.
Published: December 2007

An unusual stress controlled turbulent flow phenomenon observed in aqueous solutions of some derivatives of an unsaturated 18 carbon atom fatty acid is described. Some other unusual viscometric and rheogoniometric properties of these solutions are also discussed.

Introduction

The unique ability of certain macromolecules to reduce friction losses inturbulent duct flow has been amply demonstrated by a number of investigations, including among others. It has been suggested that this phenomenon of drag reduction is a direct consequence of viscoelastic behavior because the occurrence of markedly viscoelastic properties in solutions of certain macromolecules is characterized by the appearance of this unusual turbulent flow behavior. Recent measurements suggest that the reduced drag is a function of the ratio of elastic to viscous forces developed in these fluids. Tentative explanations put forth are based on a mode of elastic interaction between the dissolved macromolecules and the perturbed micromolecular solvent e.g., the strength of the drag reduction activity is determined by the time dependent processes or characteristic relaxation functions descriptive of the viscoelastic solution. All of the investigations of drag reduction in aqueous viscoelastic solutions involve so called "high polymers". Typical examples include synthetic polymers such as poly(acrylamides), poly(ethyleneoxides), and copolymer derivatives such as partially hydrolyzedpoly(acrylonitriles). A variety of naturally occurring polymeric substances are also characterized by the property of drag reduction, including guar gum, and the sodium salt of alginic acid.

It is generally agreed that when a high polymer dissolves, depending upon the concentration, some fraction of these macromolecules form a loose three-dimensional network. The networks and localized junctions can apparently arise for a number of reasons, e.g., as a result of a distribution of inter-and intramolecular forces, gross physical entanglements, disturbances of the flow field, and perhaps combinations of these and other effects.

viscoelastic surfactant
Certifying Agencies, Classification and Surveying Societies, Governmental and Regulatory Agencies, and Standards Writers
Authors: Gordon T. G.
Published: December 2007

Various Groups such as Certifying Agencies, Classification and Surveying Societies, Governmental and Regulatory Agencies, as well as Standards Writers all play roles in the sequence of events which are required in order that a particular piece of drilling instrumentation can be installed and operated in the jurisdiction of any particular country. The degree of involvement of each Group depends on the design of the drilling instrumentation being installed and the probability of hazardous mixtures of gases and air being present where the equipment is used.

This paper will describe, in general terms, the functions of each of the above Groups as well as locating each Group in the order in which they affect the design, manufacture, certification and installation of instrumentation. The difficulties encountered when attempting to design instrumentation which will comply with all national and international requirements is included, as well as some of the steps being proposed to lessen these problems.

It is necessary to understand the sequence of events in order to be in a position to offer products which are successful in the instrumentation market. Some basic instrumentation designs will be used as examples to depict the sequence of events from conception of design thru completion of installation.
Electrical Equipment in Hazardous Areas: Methods of Protection
Authors: Derouin D. E.
Published: December 2007

This paper presents a brief discussion of each of the principal methods of protecting electrical equipment in hazardous areas. The variations in application for different countries are mentioned as well as the relevant specifications. The material is organized in a manner to allow ease of understanding and ready reference.
Development and Use of a Gas-Tight Cement
Authors: Grinrod M. , Vassoy B. , Dingsoyr E. O.
Published: December 2007

This paper describes development of a cement slurry composition designed to cope successfully with gas migration problems. The gas blocking effect is obtained by addition of microsilica, a pozzolanic material of extremely fine particle size. Numerous tests have been performed under laboratory conditions to investigate the phenomena of gas migration through cements, and the corresponding amount of specially selected microsilica needed to effectively prevent gas flow.
Optimization of Fracture Stimulation within the North Ward Estes Field
Authors: Griffith P. J. , Madison J. S.
Published: December 2007

An investigation was initiated to optimize final sand concentrations and profitability in refracturing the North Ward Estes Field in Ward County, Texas.

This study involved the construction of a fracture enhanced production model. The model relates the final fracture width to the associated productivity increase. The fracture model data was utilized to determine the economic performance as a function of final sand concentration, accounting for operating expenses.

The simple mathematical procedure presented will aid the design engineer to quickly predict the average fracture width, frac fluid volume and total sand requirement.
Proper Application of Crosslinked Polymer Decreases Operating Costs
Authors: Mody B. G. , McKitrick R. S. , Shahsavari D.
Published: December 2007

In-situ crosslinking and subsequent gelation of water-soluble polymer solution in the vicinity of the wellbore has caused drastic reduction in water mobility of treated production wells. Relative permeability to water has been sharply decreased allowing increases in oil fractional flow toward the wellbore. The favorable changes in the reservoir near the wellbore have caused a considerable reduction in operating costs by reducing water production and associated lifting, separation and treating, transportation, and disposal costs.
Fracturing Process Control and Automation
Authors: Tomlinson H. L. , Byrd A. C. , VanBerg C. F.
Published: December 2007

As the result of studies of (1) trends in the petroleum industry (2) surveys of Halliburton field operating units and (3) surveys of operating companies, a decision was made to automate and remotely control as many well completion processes as were found to be feasible. In Phase 1 of a long range plan, fracture stimulation was automated and placed on remote control.

A dedicated team was organized to accomplish the automation. The first system is operating in the Permian Basin and has been used to fracture stimulate 30 wells as of this writing.

This paper presents the management approach to organization for the required implementation tasks. Mechanical equipment, computing equipment and software, operating procedures, and documentation are discussed. A case history of field use in the Permian Basin is presented.
Performance of Hawkins Field Unit Under Gas Drive-Pressure Maintenance Operations and Development of an Enhanced Oil Recovery Project
Authors: Carlson L. O.
Published: December 2007

In-depth studies of the Hawkins Field Unit revealed that gas drive-gravity drainage had a recovery efficiency of over 80 percent whereas the recovery efficiency from water drive was about 60 percent. These studies led to unitization of the Hawkins Field on January 1, 1975 and initiation of a gas injection project using produced gas and inert gas. This gas injection project has been very successful in converting the combination gas drive - water drive recovery mechanism to essentially all gas drive.

Recent studies indicate that immiscible gas drive of the water invaded portion of the reservoir should recover additional oil. These studies show that the minimum residual oil saturation from gas displacement of water invaded oil column is essentially the same as that from gas displacement of original oil column. Thus, potential exists for reducing the average residual oil saturation in the water invaded oil column from 35 percent to about 12 percent by gas drive-gravity drainage.

The process of gas displacement of a water invaded oil column has been termed Double Displacement Process (DDP).

This paper reviews the performance of the Hawkins Field Unit under the existing gas drive-pressure maintenance project. It also discusses the development work recently completed supporting the Double Displacement Process and the initiation of an enhanced recovery project using DDP in the East Fault Block.
Successful Application of Gas Injection to Increase Recovery in a Heavy Oil Reservoir
Authors: Perry Anthony J. , Gomez M.F.
Published: December 2007

This paper was prepared for the 96th Annual AIME Meeting to be held in Los Angeles, Calif., Feb. 19 through 23, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

The I2L-3 Reservoir of the Oveja Field, Eastern Venezuela has an estimated 445 million barrels of 150 API oil-in-place.

Production history early in the operation of the reservoir pointed to a final recovery of 6.4% of the oil-in-place, or 28.5 million barrels. This figure was considerably less than that anticipated from a simple solution gas drive mechanism acting alone, 7.5% of the oil-in-place, 0 33.4 million barrels.

Individual well behavior showed this lower recovery to be mainly the result of severe water fingering, or selective encroachment of the aquifer, into successively updip outlets.

An attempt to improve upon the apparently poor depletion behavior by secondary recovery was necessary. In view of the excellent vertical permeability of the reservoir, gas availability, and the behavior of wells next to the gas cap, gas injection was recommended.

Injection commenced in August, 1961 and performance since has been very satisfactory. Gas fingering has not been a problem. The gas-oil-ratios of updip wells have been efficiently controlled by choke changes; certain wells reached by the gas-oil contact have been effectively produced at prebreak through gas-oil ratios from lowered perforations. Positive evidence of the success achieved in increasing recovery is demonstrated by the fact that water encroachment into the reservoir has been stopped. Wells which were shut-in or producing with high water cuts are now producing clean oil or producing with substantially decreased water cuts.

As of October 31st, 1966 recovery from the reservoir totaled 24.7 million barrels, or 5.6% of the oil-in-place, and the predicted recovery of 49.9 million barrels, or 11.2%, will apparently be reached.
Modeling the Effects of Trapping and Water Alternate Gas (WAG) Injection on Tertiary Miscible Displacements
Authors: Gorell S. B.
Published: December 2007

This work investigates the effects that Water Alternate Gas (WAG) injection and trapping of oil by water have on the behavior of tertiary miscible displacements. Insights are offered into some of the trade-offs associated with the competition between improved sweep efficiency and reduced displacement efficiency associated with WAG injection. One dimensional calculations show an insensitivity of displacement efficiency to water injection over a limited range of low WAG ratios. When operating in such a manner, changing the amount of injected water has no effect on the basic solvent-oil displacement process. It only modifies what happens behind the displacement front. Mobility considerations indicate that the solvent-oil displacement is unstable. If enough water is injected with the solvent, a low mobility solvent-water bank is created which moves with the same velocity as the back of the oil bank. The WAG ratio at which these equal bank velocities occur is critical, because injection below this WAG ratio is predicted to give good displacement efficiency and poor sweep, while above this ratio mobility control and increased sweep efficiency will result at the expense of reduced displacement efficiency. In theory, injection at this "equal velocity" WAG ratio should give the benefits of both, good sweep efficiency without a reduction in displacement efficiency due to trapping. This optimum WAG ratio is shown to be relatively insensitive to the assumed level of trapping. Detailed two-dimensional simulations confirm the unstable solvent-oil displacement below the optimum WAG ratio. Mobility control and stabilization of fingers at higher WAG ratios are also confirmed. However, if trapping is important, a corresponding decrease in displacement efficiency occurs· These two-dimensional simulations also provide insight about more correct ways to model tertiary miscible displacements with simpler models, such as a mixing parameter model.
Dynamic Fluid Saturation Profiles in the Analysis of Surfactant Flooding Core Displacement
Authors: Skauge A. , Aanonsen S. I. , Graue A.
Published: December 2007

Mobilization of the residual oil by surfactant flooding involves a complex process not fully understood. The injected surfactant slug interacts with formation brine, oil, and the mineral surface. Usually, only the effluent production is available for analysis and history matching of the surfactant core floods. In this paper the analysis is enhanced by measuring the in situ saturation profiles directly during the displacement.

In order to analyse the fluid propagation during a surfactant flood, we have measured the one dimensional saturation distribution along the core as a function of time. The fluid saturation profiles are analysed by a moveable Germanium detector, measuring the radiation from a nuclear tracer added to the brine phase. The dynamics of the saturation profiles are obtanied by scanning the core several times during the displacement. The measured saturation profiles are found to correlate well with the observed effluent production.

We focus on the description of recovery improvement, how the local saturations are developing during the surfactant floods and how well numerical simulations match the results from the experimental displacements.
Surfactants for Mobility Control in High-Temperature Steam-Foam Applications
Authors: Muijs H. M. , Keijzer P. P. M. , Wiersma R. J.
Published: December 2007

Improvement of the steam-injection process by surfactants or foaming agents has already been demonstrated in field tests.

However, surfactants for steam-foam operations that perform well in tests at low temperatures often fail above 200 °C. Laboratory research on steam-foam processes as a means of profile modification in soak wells has been carried out with the aim of alleviating the temperature limitation.

First, the effect of surfactant structure was studied. As a result, sulphonates, both aliphatic and aromatic, were selected for further investigations. Besides critical parameters such as steam quality and surfactant concentration, the effects of a non-condensable gas and electrolyte were screened.

It was found that, for steam-mobility reduction by in-situ foam generation, surfactant concentration and molecular weight are the overriding parameters.

The thermal stability of the new products were studied in detail and the most economic supply formulation of these surfactants was identified. A product providing the best balance of all these aspects was tested in the field in soak wells on a large scale.

The data collected on surfactant structure and molecular weight make it possible to select surfactants with excellent performance combined with long-term thermal stability. This will enable a successful extension of the steam-foam process towards the more extreme temperature conditions encountered in various fields in the world.
Analysis and Explanation to Industrial Pilot Foam-Flooding Results on the Lao Jun Miao Field in China
Authors: Yang C-Z. , Huang Y-H. , Han D-K.
Published: December 2007

This paper describes the industrial pilot results of foam flooding for enhanced oil recovery. The results are explained by the laboratory results obtained.

Based on the experiences of the single well foam-flooding results on the Lao Jun Miao field in northwestern China, an industrial pilot foam-flooding operation was carried out in the middle of the reservoir in this field in October 1979. This pilot operation involved 18 production wells and 8 injection wells. The area of the pilot operation was 1.23 km2.

A response was obtained from a small number of the production wells, but no response was obtained from the other wells even two years later.

To analyze and explain the above-mentioned pilot results, the laboratory experiments were performed. The laboratory conditions were the same as those in the industrial pilot operation. The core sample was divided into two parts. One was swept by the conventional method, and the other was remained under its natural conditions. It was found that the precipitation occurred between the foaming agent and the water injected before the solution formed by foam with air. The amount of the precipitation depends on the concentration of the foaming agent and the salinity. The solubility of the foaming agent can be improved by adding SP-3 to the solution. The dispersion coefficient of the foaming agent (K1) between the crude oil and the formation water was equal to 1.5 in the presence of three phases. The K2 between the solid and the liquid present in four phases was greater than K1. The adsorption isotherm of the foaming agent did not correspond to that of Langmuir's model. It had a maximum value at the critical micelle concentration (C.M.C). The adsorption decreased in the presence of SP-3 and SP-6 in the foam solution.

In principle, it was found that the foam was no longer formed farther than 10 meters from the injection well.

The last part of this paper describes the results of simulation using a mathematical model. They correspond to the results of the industrial pilot and the laboratory results.
The Jobo Steamflood Project: A Preliminary Evaluation of Results
Authors: Yibirin J. G. , McGee J. H.
Published: December 2007

This paper presents an update of "The Jobo Steamflood Project-Evaluation of Results" (1). Although an adverse condition, such as the presence of a strong natural water drive in this reservoir, which prevents pressure depletion by primary steam stimulated production, 41.5% of the STOOIP has been produced, from an estimated final recovery of 45%.

Results from this mature project include a geological description of the oil bearing formations, basic petrophysical and fluids properties, a summary of oil production/steam injection statistics, well completions including thermal insulation of steam injection wells, surface facilities and associated processes with emphasis in recent technological developments, and analysis of front tracking schemes and their results.

Since preliminary results of this project were presented (1), substantial knowledge has been gained, which is being used in the planning of commercial development of Venezuela's huge Orinoco Belt.
Performance and Operation of a Successful Polymer Flood in the Sleepy Hollow Reagan Unit
Authors: Christopher C. A. , Clark T. J. , Gibson D. H.
Published: December 2007

The Reagan reservoir of the Sleepy Hollow Field in Red Willow County, Nebraska is an ideal polymer flood candidate. It has viscous oil in a high permeability sandstone with high oil saturation and fresh water available for injection. Laboratory and field testing were used to evaluate emulsion polyacrylamide polymers for injection. Laboratory core tests were of marginal use due to the lack of representative core samples. Fractional flow analysis was used as a screening tool and reservoir simulation studies were used to predict polymer flood performance. A field injectivity test showed the polymer to have much more effect in the reservoir than in the core tests. Based on these results, and a concern that injectivity loss could be excessive, a conservative selection was made of polymer molecular weight and solution viscosity. The polymer flood was initiated on February 14, 1985. An extensive quality control program was implemented to insure compliance of bulk emulsion shipments with specifications and to insure that fluids leaving the mixing plant and throughout the system were of suitable properties. Injected fluid properties were maintained within close tolerances and this effort contributed to the low loss in injection rate experienced in the flood. Swab-back sampling and pressure transient tests were used to measure the properties of injected fluids in the reservoir and to confirm that shear degradation losses at the sand face were not excessive. Water-oil ratios have declined from 45 to 17 in the polymer flood area, which contains 10 injectors and 45 producers. Polymer breakthrough has not been excessive and no emulsion problems have been encountered in the produced fluid system. Corrosion has increased since polymer breakthrough and there is indication of partial plugging of producing wells. Beginning in 1986, due to the downturn in oil prices, efforts were made to lower operating expenses by reducing injection rates and polymer concentration. These changes have significantly reduced operating expenses and have consequently enhanced the economics of the flood. Results to date indicate the flood will be a technical and economic success.
A Study of the Mechanism of Oil Displacement Using Water and Polymer in Stratified Laboratory Core Systems
Authors: Sorbie K. S. , Walker D. J.
Published: December 2007

Oil displacement experiments are reported which were performed in stratified rectilinear systems consisting of two lower permeability sandstone slabs, enclosing a central high permeability layer made of unconsolidated glass ballotini. The adjacent layers were in good flow communication, except for a very small region close to the outlet. This arrangement allows the crossflow mechanisms that occur when the viscosity of the displacing brine is increased by adding a water soluble polymer. These mechanisms cannot be assessed by performing experiments in one-dimensional cores or packs. Results of oil displacement experiments are presented for different mobility driving fluids, in which glycerol is used to viscosify the aqueous phase. Carbon-14 and chlorine-36 are used as radioactive tracers in the experiments. The effluent fluids from each layer were collected and analysed to produce data on the cumulative oil recovery, watercuts, flow rates in each layer, viscosities and concentrations of radioactive tracers.

The results of these oil displacement experiments were modelled using computer simulation, and a very good match to the experiments was obtained. This simulation work confirms the flow mechanisms involved when water soluble polymers are used to increase the oil production from stratified reservoirs.
Simulation of Small Chemical Slug Behavior in Heterogeneous Reservoirs
Authors: Clifford P. J.
Published: December 2007

In simulating field performance of polymer and micellar flooding, it is frequently necessary to calculate the behaviour of chemical slugs which are small compared to the well spacing, and not much larger than the normal gridblock dimension. A polymer slug in a heterogeneous reservoir will then be subject to disruption from numerical dispersion, viscous crossflow and viscous fingering. The problem addressed in this paper is whether oil recovery from the slug can be simulated without an impracticable degree of grid refinement.

Analytical modelling is used to explain the process of slug disruption by viscous crossflow in a layered reservoir, and to demonstrate the close relationship between crossflow and oil recovery. Some of the concentration fronts will spread even in the absence of dispersion. Numerical simulation is used to examine the sensitivity of slug behaviour to grid refinement, dispersion, slug size and viscosity and viscous fingering.

It is shown how a coarsening of the gridblock structure leads to large qualitative changes in slug flow and the movements of polymer within the reservoir. However, it is also demonstrated that the quantity of incremental oil recovery is much less sensitive to numerical dispersion, over a wide range of likely slug properties. This allows a much more adequate calculation of polymer flood performance in very coarse grids than would be expected from the ratio of slug to gridblock size, and is most important in permitting practicable reservoir simulation of this EOR process.
The Role of Adsorption in High pH Flooding
Authors: Ramakrishnan T. S. , Wasan D. T.
Published: December 2007

The high pH flooding model presented earlier (SPE14950) is extended to include the effects of adsorption of sodium on the mineral surface. The problem is formulated by conserving various species present in the system. As in the previous model, it is presumed that the lowered interfacial tension is the cause of the improved fractional flow of the oleic phase.

The governing system of equations is solved by the generalized Riemann invariants technique. Although the formulation is an extension of the earlier work it is shown that when mineral interaction is present, composition paths (simple wave curves) are inadequate in evaluating the uniqueness of the solution as long as the injected composition lies in the optimum or over-optimum range. The problem, therefore, is solved by first deriving a differential expression for shock curves. From this expression, the notion of critical point is introduced in constructing a unique solution.

The predicted profiles and histories of the model for both secondary and tertiary stimulated recoveries are presented. A new and surprising result of the model is that for over-optimum systems chemical component adsorption could change the ultimate recovery of oil even for a continuous injection of alkali. Besides delaying the chemical front, sodium adsorption on the solid surface is seen to reduce the influence of the low (optimum) interfacial tension region in recovering oil. A major conclusion of the earlier paper that a favorable viscosity ratio ensures that the optimal region influences oil recovery is found to be true. However, the extent to which it does so is found to be reduced due to adsorption. An implication from these results is that computations specific to a system would be necessary before optimal choices of alkali and salt concentrations are made.
Reservoir Modeling To Verify Geologic and Petrophysical Data: A Case Study
Authors: Ucok H.
Published: December 2007

Reservoir modeling was utilized for resolving the large differences in core versus open-hole log derived petrophysical data gathered during the development of the Upper Repetto Reservoir of the Santa Clara Unit. Additionally, the model was utilized to confirm the presence of a sealing fault that was thought to be crossing the reservoir in a north-south direction.

The availability of four years of historical performance at the time of the modeling study along with some pressure transient data were viewed adequate to resolve the differences in petrophysical data and also to verify the presence of a north-south crossing fault.

The petrophysical properties in question, i.e., porosity and water saturation, as well as the location and the shape of the flow barrier, were all considered to be secondary history match variables behind the relative permeability during the history matching process. The reservoir description was accepted as correct upon achievement of a good history match between the actual and predicted performances.

An excellent agreement was achieved between the measured gas and water rates in field wide and in individual wells by modest adjustments in relative permeability using a reservoir description which was based on log derived porosity and core derived water saturation values. The reservoir description also included a linear flow barrier between the two domes. Thus, in the Upper Repetto reservoir the log derived porosity (ϕ) and core derived water saturation (Sw) values were verified to be correct individually or at least in combination (in the absence of other information). This was somewhat expected, especially for the water saturation. Because of the presence of abundant conductive minerals in the formation, the large error in water saturation was believed to be associated with the log derived values.

The presence of a flow barrier again was confirmed by an excellent history match in field wide and in individual well performances, particularly in those wells that were in close proximity to the flow barrier.
Effective Application of Beam Pumping Diagnostics
Authors: Ford W. H. , Svinos J. G.
Published: December 2007

Chevron Oil Field Research Company has developed computer programs for troubleshooting rod pumping systems. These programs are successfully applied by nontechnical personnel in field locations that cover 95% of Chevron's rod pumping wells. The key reasons for this success are management support as well as program features and unique capabilities designed to simplify technology application. The analysis program (SADA) uses the wave equation to model the rod string and an exact pumping unit kinematic model. SADA can perform downhole calculations even with a solid line dynamometer card. It can determine the existing counterbalance moment from crank and counterweight information along with the counterweight positions required to balance the unit. Crank speed variation and inertia torques can be considered without measuring motor speed. Furthermore, pump intake pressure, fluid level and net stroke can easily be determined from an interactive pump card analysis. An auxiliary program to SADA called EXPROD, employs a pattern recognition scheme and expert knowledge to interpret SADA's results and diagnose well conditions. Results of applying this technology are presented as are recommendations for effective technology transfer.
Field Examples Of Barrier Detection With Unsteady-State Techniques
Authors: Schrenkel Jack
Published: December 2007

PUBLICATION RIGHTS RESERVED

This paper is to be presented at the 36th Annual Fall Meeting of the Society of Petroleum Engineers of AIME in Dallas October 8–11, 1961, and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than 300 words, with no illustrations, unless the paper is specifically released to the press by the Editor of JOURNAL OF PETROLEUM TECHNOLOGY or the Executive Secretary. Such abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in JOURNAL OF PETROLEUM TECHNOLOGY or SOCIETY OF PETROLEUM ENGINEERS JOURNAL is granted on request, providing proper credit is given that publication and the original presentation of the paper.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and considered for publication in one of the two SPE magazines with the paper.

Two field case histories involving three wells are presented, showing the effect of faulting on the pressure buildup and pressure drawdown characteristics. Example 1 has several unfavorable conditions existing - yet it shows there is a barrier present. Example 2 has two wells with drawdown curves measuring the distance to the major fault with good precision.

It is concluded that barrier detection methods, using the unsteady-state techniques, are a useful exploration tool.

Introduction

The theory of barrier detection was published by Horner in 1951. In his paper, Horner showed how formation capacity could be obtained, what the effect of boundary conditions would have on the final static pressure, and how distances to barriers could be computed from anomalous buildup tests. Since the publication of Horner's paper, Dolan and Coauthors, and Jones have presented the results of pressure buildup and pressure drawdown tests that were near faults or other barriers.

Presented here is an example which confirms the existance of a known fault and a second example which predicted the distance to a fault, which subsequent drilling proved to be correct.

THE THEORY OF BARRIER DETECTION

Horner developed his theory of barrier detection by the superposition of the solution of two equations. One of the equations was for the well and the other for the image well located across the barrier. The barrier is normal to the line of sight from the well to the phantom well.