bluuebunny/crossref_metadata_2025 huggingface dataset:
Data Base for Eastern Gas-Bearing Formations: Development and Application
Authors: Ameri S. , Aminian K. , Yost A. B.
Published: December 2007

The Appalachian Basin contains a number of low permeability formations which have produced natural gas for many years. The lack of reliable data/information pertaining to parameters controlling production of natural gas from such low permeability (tight) gas bearing formations has hindered their continuous economic development. The data that have been available usually consisted of isolated data points held within the company files without a mechanism for comparison with other similar formation(s) in the Appalachian Basin. This has effectively prohibited the development of any kind of statistically base from which one might infer the production mechanism, predict performance, determine the responsiveness of formations to stimulation treatments, and delineate the high potential areas for future development.

The overall goal of this study is directed towards answering some of the questions needed to help the eastern low permeability formations become viable candidates for future development. This research project endeavors to solve the problem, at least for a subset of the tight gas bearing formations consisting of Big Injun, Berea, Benson, Oriskany, Big Six and Tuscarora that exist in the Appalachian Basin.

The research objectives have been achieved through:

Development of a Database through collection, interpretation, and compilation of data relative to completion, production, and stimulation on the eastern tight gas formations so that a good research foundation can be established. Analysis of the data so that the key parameters affecting gas production can be identified and quantified.

It should be noted that the Database contains data on over 1200 wells in Kentucky, New York, Ohio, Pennsylvania, Virginia, and West Virginia. The information has been collected from a variety of sources including many gas companies.

The Database can be utilized to identify and evaluate a range of lithological, reservoir, and treatment parameters which control the production of natural gas from the eastern tight gas formations. The utilization of the Database and its applications relative to identification and evaluation of the potential areas for future economic development are discussed in this paper.
Accurate Formulas for Calculating the Water Influx Superposition Integral
Authors: Vogt J. P. , Wang B.
Published: December 2007

For quickly responding aquifers, the widely used step pressure (SP) formula for evaluating the water influx superposition integral is inaccurate as it is normally employed. Using the SP formula in the material-balance-with-water-influx equation causes it in turn to give inaccurate results. A totally general, linear pressure (LP) formula is introduced that more precisely evaluates the water influx superposition integral and leads to the following advantages when used in the material balance equation: (1) the. original gas or oil in place (OGIP/OOIP) and aquifer parameters can be determined earlier in a reservoir's life, (2) reservoir pressure can be predicted more accurately once the OGIP/OOIP and aquifer parameters are known, and (3) OGIP/OOIP and equivalent aquifer parameters can be determined for reservoirs with a variety of drive mechanisms-including shale water influx and rock compressibility – without knowing what the actual drive mechanism is. It is also pointed out that a computationally efficient linear pressure recursion (LPR) formula developed by Leung for reservoir simulators has the same accuracy as the LP formula derived in this paper.
Determination of Volume, Type, and Distribution Modes of Clay Minerals from Well Logging Data
Authors: Fertl Walter H. , Chilingar George V.
Published: December 2007

Typical shaly clastic reservoir rocks and/or shale intervals frequently contain varying amounts of different clay minerals. Most common clay minerals exhibit significant differences in their basic properties, including chemical composition, matrix density (g/cc), photoelectric cross section (Pe, barns/electron), hydrogen index (HI), cation exchange capacity (CEC, meq/lOOg), potassium (percent), uranium (ppm), and thorium (ppm). These different properties and associated interpretive models allow the identification and quantitative evaluation of the major clay mineral groups such as smectite, illite, kaolinite, and chlorite via geophysical well log responses.

Based on density, neutron, and natural gamma ray spectral data, two important formation parameters, clay density (ρcl) and neutron response to 100% clay (Ncl), can be determined at every depth level over the computed interval of interest. No average clay property values from adjacent shale formations are required as input. Hence, the constraints inherent to other techniques, e.g., the assumption that clay properties in the clastic reservoir and adjacent shales are identical, do not apply.

Having determined the two critical clay parameters, ρcl and Nd, the clay volume (Vd) is calculated simultaneously from both the potassium and thorium values. This Vd is essentially independent of the clay types. These three parameters (ρcl, Nd, Vd) then allow for the calculation of two important reservoir parameters at each depth level, namely the cation exchange capacity (CEC) and the hydrogen index (HI). The resulting CEC and HI values then define the types of clay minerals present. On a CEC versus HI crossplot, the smectite (montmorillonite), illite, and kaolinite/chlorite are grouped at three separate, clearly defined positions.

Recently developed interpretive refinements incorporate the photoelectric cross section value, Pe, which also allows quantitative differentiation of kaolinite and chlorite. Hence, all four major clay mineral groups (smectite, illite, kaolinite, chlorite) can be evaluated via modern logging measurements.

Furthermore, it is well known that the type of clay mineral distribution in a reservoir rock significantly affects the effective reservoir porosity, effective water saturation, permeability, and hence, intervalproducibility. Different clay mineral distributions, such as clay dispersion, clay lamination or structural clay, will affect effective reservoir porosity (ϕc) and permeability in a drastically different manner. These different clay distribution modes also can be determined from the above mentioned well logs.

Several field examples illustrate these concepts as applied to well completion, formation damage, and detailed clastic reservoir characteristics.
Iron Control Additives for Limestone and Sandstone Acidizing of Sweet and Sour Wells
Authors: Hall B. E. , Dill W. R.
Published: December 2007

Iron precipitation has been recognized as a significant problem in acidizing operations for over 30 years. Deposits of iron compounds in tubulars combined with iron compounds in the formation determine the amount of iron dissolved by the acid and therefore, the severity of the iron problem. Data from the analysis of recovered acid on previous jobs canbe used to predict the concentration of iron that may need to be sequestered on future jobs.

Iron sequestering additives may present compatibility problems. Specific types of compatibility problems may be encountered when acidizing limestone formations with HCl, while other compatibility problems may be encountered when acidizing sandstone formation with HC1-HF blends.

Iron sequestering additives may lose effectiveness because of degradation. Degradation properties of less stable additives are discussed. The iron sequestering additives currently used are described and their effectiveness is compared using laboratory test data.

Iron sequestering in the presence of sulfides present unique problems which are explained. A system for sequestering iron in the presence of sulfides is described. Job descriptions and results from acidizing operations are presented.
Reduction Feasibility of Itabirite Mud Abrasion
Authors: Bizanti M. S. , Moonesan A. , Caruthers R. M.
Published: December 2007

Barite consumption in the United States is a direct result of the need for weighted muds in oil and gas wells drilled. Barite demand in the petroleum industry is projected to increase from 2.65 million tons in 1983 to 5.0 million tons in the year 2000. The United States reserves of barite, estimated at 30 million tons, are not adequate to fill the projected cumulative demand of about 60 million tons by the year 2000.

This paper evaluates the benefits and problems associated with itabirite (micaceous hematite) as a weighting material in water-base muds. A laboratory investigation compared fresh water samples of barite and itabirite, and the effect of addition Kelzan XCD polymer. Three different ranges of particle size of itabirite were selected for the tests. Particle sizes between 74 and 125 microns, between 44 and 74 microns, and smaller than 44 microns were used. Thirty-minute abrasion tests were conducted with a modified Hamilton Beach Blender at 9800,11200,12570, and 14350 rpm.

Rheological properties, filtration properties, and abrasiveness were studied and analyzed. Itabirite exhibited better rheological characteristics than did barite. Itabirite could increase penetration rate since a lower solids content can be used to obtain proper weight. Itabirite did not exhibit good filtration properties and was more abrasive; however, the feasibility of using itabirite as a weighting material was enhanced with a finer particle size distribution and by use of a determined amount of Kelzan XCD polymer to control filtration and to act as a coating agent to lower the abrasiveness.
Use of Low-Density, Gravel-Pack Material Improves Placement Efficiency
Authors: Hudson T. E. , Martin J. W.
Published: December 2007

The success of a gravel-pack completion depends on placement of gravel in the perforation tunnel area and the screen-casing annulus. Wellbore deviation is one of the predominant factors affecting gravel placement. As wellbore deviation increases, the gravitational forces and carrier fluid limitations may result in gravel settling (duning) and an incomplete packing of much of the perforation tunnel area, as well as a premature screenout of the screen-casing annulus.

A completion technique is introduced that eliminates problems associated with gravel settling. The technique uses buoyancy forces to counter the gravitational forces on the gravel particulate. Particulate settling is minimized by decreasing the ratio of the particulate density (Dp) to the base fluid density (Dc). Verification of the concept includes test results from a gravel-pack model. The model is 18 ft long with an inside diameter (ID) of 6.2 in., a screen and blank pipe size of 2-7/8 in., and a working pressure of 1,000 psi. The blank pipe length is 6 ft and the screen length is 12 ft. There are 20 perforations that include a chamber to simulate a void space behind the casing.

Test results include gravel-pack efficiency for variations in base fluid properties, wellbore deviation up to 90° (horizontal) and particulate density/ base fluid density ratios (Dp/Dc) from 2.65:1 to 0.8:1. Recommendations for a treatment technique and low-density particulate specifications also are included.
Diamond-Enhanced Hammer Bits Reduce Cost per Foot in the Arkoma and Appalachian Basins
Authors: Reinsvold C. H. , Clement J. , Oliver M. , Witt C. , Crockett J.
Published: December 2007

Polycrystalline diamond technology and down-hole hammer drilling have been combined to create a new type of bit. This bit, the diamond enhanced hammer bit, features diamond coated tungsten carbide inserts for improved cutting structure wear resistance. By improving bit life and increasing penetration rates, these bits have been able to reduce cost per foot in the Arkoma and Appalachian Basins.
Separating Bit and Lithology Effects from Drilling Mechanics Data
Authors: Falconer I. G. , Burgess T. M. , Sheppard M. C.
Published: December 2007

Most real time drilling interpretation is performed using some sort of normalized rate of penetration to infer changes in lithology and diagnose the condition of the bit. This frequently leads to ambiguous or confusing results because it is impossible to separate all bit effects from lithology effects with only one measurement. This paper shows how a second measurement, downhole torque, can be used with rate of penetration to confidently separate the bit effects from the lithology effects when drilling with milled tooth or PDC bits.

Simple drilling equations for rate of penetration and bit torque are derived and compared with well known formulae. These lead to simple "quicklook" interpretations which can be made at the wellsite with a hand calculator. A detailed analysis can be performed on a wellsite computer.

Many field case studies were made to examine the effects of lithology changes on the drilling response of milled tooth and PDC bits. A few of the studies are presented. The results indicate that:

changes in bit torque can be used to broadly classify the lithology into three categories, namely: porous, argillaceous (shaly), and tight, corresponding to high, medium and low torque respectively, trends in bit torque and rate of penetration (ROP) in shale type formations can be used to separate the wear of milled tooth and PDC bits from changes in shale strength, it was not possible to interpret bit wear in non-shaly type formations, surface drilling measurements can be insensitive to major formation changes (eg. sand/shale boundaries), particularly in deviated wells.
Directional Drilling Azimuth Reference Systems
Authors: Wright J. W.
Published: December 2007

This paper will examine the primary azimuth reference systems currently used in directional drilling and their interrelationship when used in this application. This will include True North and Magnetic references with particular detail given to Grid Coordinate systems (ie. UTM, Lambert, Geographic, and Local). A simple field-proven method is also presented to help avoid confusion when converting from one system to another.
Accurate Surveying: An Operator's Point of View
Authors: de Lange J. I. , Twilhaar G. D. Nijen , Pelgrom J. J.
Published: December 2007

The achieved survey accuracy from the modern survey tools can be quantified by analysis of run data. Knowledge of the achieved accuracy, often better than the beforehand estimated accuracy, could result in reduced surveying cost and less rig time spent on surveying. Survey companies are urged to improve QA/QC and to provide the operator with ‘simple’ yardsticks with which to judge actual performance.
Technical Considerations in the Certification of Drilling Units for Worldwide Service
Authors: Thomas R. L. , Richardson K. L. , Abad E.
Published: December 2007

Technical considerations in the certification of Drilling Units for World Wide Service.

The design of the latest generation of offshore drilling units for operation world-wide has presented the greatest challenge to the offshore industry since drilling operations first moved offshore over thirty years ago. None have been more challenged than the electrical and instrumentation engineers tasked with the design of the power and control systems that enable these units to maintain station and conduct drilling operations under adverse environmental condition. An integral part of their job is to arrange the system and select components in conformance with the requirements of the flag state, various coastal states, certifying authorities and classification societies.

Such regulations vary not only in scope but also in the manner in which identical concerns are addressed. Designing for compliance with all the pertinent requirements presents a complex task for the engineer.

This paper will outline the major requirements pertinent to electrical and electronic systems of the regulations and rules of IMO, the United States, Canada, United Kingdom, Norway and one major classification society, highlight the major differences in their scope and approach and outline suggestions on how simultaneous compliance can be achieved.

The authors will draw on ABS’ experience in the classification and certification of several drilling units recently completed or presently under construction.
A Shallow Gas Research Program
Authors: Grinrod M. , Haaland O. , Ellingsen B.
Published: December 2007

Operational problems associated with the occurence of shallow gas in offshore drilling led Statoil to initiate a massive research program. The program consisted of the following subprojects: Revised drilling procedures, shallow gas drainage, multistage cementing, gas tight cement, diverter systems, rig ventilation systems and emergency anchor release.

Emphasis in this paper is placed on the experience from the West Vanguard blowout, and results from the subprojects on diverter systems, drilling procedures, quick anchor release and ventilation systems.

Other papers (reference 1, 2) give information on development of gas tight cement, stage cementing and additional background on shallow gas drainage.
Make-up of Fiberglass Tubulars
Authors: Stringfellow William D.
Published: December 2007

The use of downhole Fiberglass Reinforced Plastic (FRP) tubulars to combat the effects of aggressive corrodents is increasing. Field experience indicates that the significant differences between the more conventional metallic tubulars and FRP tubulars are not clearly understood. This same experience has indicated a need for specialized tools for handling and make-up of FRP tubulars.

This paper presents a basic level overview of the material properties of FRP tubulars, including a comparison with K-55 steel tubulars, with emphasis on the impact these properties have on the make-up of the API 8 Round connection. Also presented is a description of a power tong developed specifically for the make-up of FRP tubulars. The discussion will include design parameters, used in the design of this tong, as well as laboratory and field test results.
Measurement of BHA Vibration Using MWD
Authors: Close D. A. , Owens S. C. , MacPherson J. D.
Published: December 2007

Excessive drill string vibration can lead to partial or catastrophic failure of bottom hole assembly (BHA) components. This paper presents data from a microprocessor based downhole vibration data acquisition and recording system, located within a host MWD (Measurement While Drilling) collar in the BHA.

Four case studies of vibration levels attained during commercial drilling operations are presented. These examples include vibration monitoring during reaming, drilling a casing shoe, and drilling new formation. Generally, lateral accelerations were an order of magnitude greater than longitudinal accelerations. In one example, catastrophic failure of MWD components resulted from sustained high-level lateral vibrations.

Data collected to-date has been used to optimize BHA components and define the down hole vibrational environment. Future information obtained by the monitoring system will be of value in verifying and calibrating computer models.
Evaluation and Implementation Of CO2 Injection at the Dollarhide Devonian Unit
Authors: Poole E. S.
Published: December 2007

A carbon dioxide (CO2) injection project has been underway at the Dollarhide Devonian Unit since May 1985. Through August 1987, 5.8% hydrocarbon pore volume (HCPV) of single slug CO2 had been injected into the Unit's Phase I CO2 area with very little breakthrough at producers. Dollarhide's total lack of premature breakthrough is unique among West Texas CO2 floods and is indicative of unusually high CO2 sweep efficiency. Through pattern realignment and injection of a 30% HCPV of CO2, the project is expected to recover 19% original oil in place (OOΙΡ), or 26.3 MMSTB.
Prediction of Waterflood Performance in Stratified Reservoirs
Authors: Tompang R. , Kelkar B. G.
Published: December 2007

Crossflow between adjacent layers plays an important role on water flooding performance in a stratified reservoir; however, the analytical solutions describing the crossflow effect are possible only under limiting conditions: (i) where viscous forces are dominant (no crossflow); and (ii) where vertical equilibrium exists (gravity and capillary dominated displacement). This study analyzes the effect of crossflow on the waterflooding performance by comparing simulator results under actual flooding conditions with the approximate analytical solutions. The parameters varied include the injection rate, vertical permeability variation, ordering of beds, mobility ratio and the ratio of vertical to horizontal permeabilities. A five beds, linear model was used under wide range of operating conditions.

Based on the study, it was observed that the oil recovery and cross flow index were dependent on the value of RL (effective length to height ratio) for favorable mobility ratios, and on the value of RD (vertical to horizontal pressure gradients ratio) for unfavorable mobility ratios. Ranges of RL and RD were established for which approximate analytical solutions are valid. For the intermediate region (where both viscous and gravity forces are important), empirical correlations for crossflow index were developed.
New Techniques Lead to Better Completions in Red Fork and Other Low-Permeability Formations
Authors: Rose R. E.
Published: December 2007

The Red Fork, a member of the Pennsylvanian age Cherokee group in western Oklahoma and the Texas panhandle, has been the target for major drilling and completion activity for several years. During 1979-81, several wells were completed in the Red Fork with varied results. The history of these completions and treatments has been traced and determinations have been made as to why post-1981 completions have shown better results than pre-1981 completions. From these results and with the aid of computer monitored pump-in/flow-back tests, the Red Fork may be "typed" by an empirically derived correlation. Thus completions can be designed for this particular "typed well" response.

With the information obtained from the pump-in/flow-back test (i.e., maximum proppant concentration, maximum pumping time, and fracture closure pressure), a stimulation treatment may be designed for maximum proppant placement. After placement of the proppant, a technique may be applied to induce closure so proppant is trapped in the producing interval instead of depositing in the bottom of the induced fracture, which may not be a portion of the producing interval. An example would be a large shale section or a section having such low permeability or porosity that is below the perforated section such that production may be below the economic payout of the well.

This paper presents (1) field treatment histories, (2) analysis of completion success pre-and post-1981, and (3) methods of job design to help achieve maximum proppant placement in the Red Fork Formation.
The Critical Production Rate in Water-Coning System
Authors: Abass H. H. , Bass D. M.
Published: December 2007

Water coning is the mechanism in which the oil/gas – water contact locally rises toward the perforated interval in a partially penetrated oil/gas well.

Numerical and physical models have been built to study the performance of water coning under different boundary conditions. A fully implicit, strongly coupled mathematical model was formulated to handle rapid pressure-saturation changes. On the other hand, a plexiglass model was constructed to obtain a qualitative and quantitative description of water-coning phenomenon. An analytical description of water coning under different flow conditions was developed.
Sucker Rod Pumping Unit Diagnostics Using an Expert System
Authors: Derek H. J. , Jennings J. W. , Morgan S. M.
Published: December 2007

This paper presents an application of expert system technology to diagnose sucker rod pumping units. This approach helps to capture expert's knowledge, often held by a few individuals, and make it available wherever a personal computer is available. The captured knowledge becomes permanently recorded and can be updated as the system solves more difficult problems.

A rule-based expert system has been developed to help the user analyze the subsurface pump problems. Based on interviews with an industry recognized beam pumping expert diagnostic rules were formulated to identify problems within the subsurface pump. The system utilizes auxiliary programs to obtain information necessary in the analysis process. The user is also given access to the information obtained from the expert thereby transfering the expert's knowledge to the user.
Three-Phase Relative Permeability Correlations
Authors: Baker L. E.
Published: December 2007

Several correlations have been proposed for prediction of three-phase relative permeability from two-phase data or from saturation/capillary-pressure relationships. These include the models of Stone, Hirasaki, Corey et al., Naar and Wygal, Land, Aleman, and Parker et al. This paper compares predictions of these models with predictions of two additional models (saturation-weighted interpolation and true-linear interpolation). The comparison is made using all the published three-phase experimental relative permeability data complete enough for application of the models.

The comparison shows that the models are often not very good predictors of the experimental data. This points out a need for better relative permeability models in cases where three-phase flow may have a significant effect. In most cases, straight-line interpolation or saturation-weighted interpolation between the permeabilities at the two-phase boundaries of the three-phase flow region provided a better fit of the experimental data than did the theoretically-based models.

The paper also demonstrates the utility of comparing the effects of different relative permeability models before using them in a reservoir simulation. Sometimes the result of a simulation can be heavily biased by the choice of relative permeability model used.
Offshore Operations In Cook Inlet, Alaska
Authors: Goepfert B.L.
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.

Offshore operations in the hostile environment of Cook Inlet, Alaska, began in 1959 with the joint seismic surveys of some 11 companies in the waters of the upper Cook Inlet. In 1962 several companies drilled exploratory wells on leases purchased in 1961. The first all-weather, all-year drilling and production platform was installed in the Inlet in the fall of 1964. Presently there are six platforms operationally complete, one partially completed, and four planned for installation in 1967, for a total of 10 drilling and production structures in the Inlet by the end of 1967. The first crude oil flowlines were installed in 1965 and many more additional lines were added in 1966, with plans to re and expand the flowline network in 1967.

The problem associated with Cook Inlet which set it apart from other offshore areas are related to the remoteness of the area from support facilities and the hostile environment, specifically the 30-foot tidal range and accompanying swift currents, and the range of temperatures which cause the Inlet to ice over in the winter months.

Nevertheless, progress is being made in developing the mineral resources underlying the Inlet and solutions are being found for the many special problems which should eventually enable the efficient drilling and production of the hydrocarbon resources hidden under the icy waters of the Inlet.

Introduction

In 1959 some 11 oil companies shared the cost of obtaining basic seismic data in the upper Cook Inlet, thus beginning one of the most challenging drilling and production programs in the history of our far-ranging search for reserves of energy to provide the ever-increasing demands for fuel needed in our modern society.
Kinetics of Silica Dissolution and Hydroxyl Ion Consumption In Alkaline Flooding
Authors: Saneie Shahrouzeh , Yortsos Y. C.
Published: December 2007

In this paper a mathematical model simulating the kinetics of silica dissolution and hydroxyl ion consumption in a typical alkaline flooding environment is developed. The model is based on the premise that dissolution occurs via hydrolysis of active sites through the formation of an intermediate complex, which is in equilibrium with the silicic acid in solution. We consider equilibrium ion exchange at the silica surface and ionization reactions of the silicic species in solution. Both static (batch) and dynamic (core flood) processes are simulated to examine the sensitivity of caustic consumption and silica dissolution to process parameters, and to determine rates of propagation of pH values.

The model presented provides a quantitative description of the quartz-alkali interaction in terms of pH, salinity, ion exchange properties, temperature and contact time, which are of significant importance in the design of soluble silicate flooding processes. The latter are shown to minimize or eliminate silica dissolution and caustic consumption, in agreement with recent suggestions. An analysis of the batch processes shows that OH- consumption results from a combination of both ion exchange and silica dissolution. Higher values in the salinity level and in the ion exchange constant lead to a net increase in OH- consumption despite the decrease in the dissolved silica.

The opposite effect arises in core flood processes, where the ion exchange is beneficial in arresting the OH- consumption and the decline of pH, in an upstream region. This (plateau) region is characterized by a constant concentration of Na+, the silica-alkali interaction follows a batch-like behavior and pH profiles become stabilized. A region of decline to the initial values precedes this ion exchange plateau. For all practical purposes, the relevant quantities are the pH level at the front of this plateau, determined from the batch analysis, and its velocity of propagation. Thus, the rate of the pH decline increases with the Damkohler number (C), and equilibrium pH values may be reached well before breakthrough for high enough C. The equilibrium values are independent of salinity or the ion exchange constant, although the conditions for establishing the equilibrium before breakthrough and the frontal velocities are functions of these parameters. For instance, the front velocity is found to decrease as the ion exchange constant increases.
Multiphase Pressure Buildup Analysis: Field Examples
Authors: Ayan C. , Lee W. J.
Published: December 2007

Multiphase pressure buildup tests from a West Coast Field were analyzed using a variable bubble point, black oil simulator. By history matching the observed pressure data, possible explanations were found for unusual buildup behavior, for which conventional analysis methods were ambiguous.
An Improved Cyclic Steam Stimulation Model for Pressure-Depleted Reservoirs
Authors: Sylvester N. B. , Chen H. L.
Published: December 2007

An improved cyclic steam stimulation model for predicting heavy oil recovery from pressure-depleted reservoirs is presented. The model incorporates many of the advantages of existing models with some important modifications and improvements. A modified gravity drainage inflow equation is used to predict the production rates for both oil and water. The heated radius equation is obtained by modifying the original Marx-Langenheim relation to account for wellbore heat loss during injection and for the heat remaining in the reservoir from previous cycles. A new water saturation equation, which includes condensed steam from previous cycles, is presented to simulate changing saturation during production. The model permits the direct input of field data or correlations for relative permeability versus water saturation.

Utilizing only one adjustable parameter, the model produces an excellent history match of oil production and water cut for the seven cycle, Midway Sunset field test. In addition, the model is shown to reliably predict oil production without the need to adjust field data.
A Simplified Modeling Study of Vickers East Waterflood Project in Inglewood Field
Authors: Sankur V. , Emanuel A. S.
Published: December 2007

This paper describes and evaluates the application of stream tube modeling techniques to historical and projected waterflood response for the Vickers East reservoir in the Inglewood field. The technique was successful in predicting the past production history and WOR behavior through the initial flood and the subsequent realignments.

Vickers East, like most other L. A. Basin reservoirs, has a complex geology. It is characterized by up to 1400 feet of gross thickness, cut by numerous faults and composed of very thin sand and shale beds. The field has been under waterflood since 1955 and had three realignments in its history. To evaluate waterflood performance and to assist reservoir management, a modeling study was initiated. Due to time and cost requirements, a 3-D fieldwide finite difference simulation study was considered impractical.

Despite the complexity of the reservoir, a relatively simple stream tube model was developed to represent historical performance and to predict response to a recent realignment project. The model uses a numerical solution for the stream function equation and an approximate mapping technique to reflect the change in streamlines as wells are drilled or converted. The geology was represented by six equivalent layers determined from the field measured Dykstra-Parson's coefficient of 0.6.

The past performance was matched well by using historic gross fluid rates, with minor parameter adjustments. The model was used to predict the response of the latest realignment. The early field performance lags the production forecast for reasons explained in the text.

This study demonstrates that stream tube methods can be effective in designing new waterfloods or realigning old ones in complex reservoirs. Various scenarios can be run at low cost to guide realignment decisions and the production response--with some modifications-- can be used in economic analysis. This methodology offers more flexibility than decline curve analysis and much lower cost than rigorous 3-D finite difference simulation.
Optimizing Cement Design for Improved Job Results
Authors: Evanoff J. I. , Cook C.
Published: December 2007

Until recently, wells in the northern Sacramento Valley had often been troubled by interzonal communication, as evidenced by poor bond logs necessitating frequent remedial cement work. Cement designs commonly used in this area proved ineffective in solving this problem. Analysis of the cementing failures in this gas field led to the realization that a total reevaluation of the cementing program for this field was required to determine the nature of the poor cement job results obtained.

An effective cementing program was eventually developed based upon findings published in research papers on cementing practices, and on field experience already obtained in this particular area. This cementing program focused on cementing practices including displacement mechanics, slurry design, and physical elements such as cement column length. Through a thoroughly engineered approach to well evaluation and cement job design, a consistent methodology for cementing practices was developed. Two key elements of the successful cement design included use of controlled fluid loss cement slurries, and short cement column lengths.

Though this paper presents a summary of field experiences specific to the conditions prevalent in the northern Sacramento basin, the methodology should be applicable to any given set of conditions either on a field-wide or individual well basis. An examination of this analytical, problem solving cementing design technique will show operators and service companies a method to help minimize job design flaws, and to optimize cementing results.
The Characteristics of a Low Temperature In Situ Shale Oil
Authors: Hill George R. , Dougan Paul
Published: December 2007

A 40 degrees A.P.I. crude shale oil has been produced from the Green River Formation in the Piceance Creek Basin of Colorado by injection of hot natural gas at a controlled temperature. The quality of the shale oil differs very markedly from the customary shale oil from the same formation produced in a high temperature retort. The characteristics of the oil fractions have now been determined. These include distillation analyses, viscosity, and pour point determination.

Kinetic data on the production of the shale oil under the conditions used in the field, but carried out on a small scale in the laboratory will be presented. A possible mechanism for the production of this oil, as well as a mechanism for the production of shale oil by more usual high temperature methods will be presented.

TEXT

Various methods for the production of shale oil by in situ techniques are being investigated in the United States. The method with which this paper is concerned involves the use of hot natural gas as the energy conveying medium to convert the kerogen in the oil shale to a petroleum like liquid. The basic concept, which was developed by the late J.L. Dougan of Equity Oil Company and tested in the Fuels Engineering Department laboratories at the University of Utah and subsequently field tested in the Piceance Creek Basin of Colorado, is basically a low temperature conversion and distillation process. Natural gas is heated to a temperature below its thermal decomposition temperature and injected through an insulated pipe into the Green River Oil Shale formation where it loses its heat rapidly to the oil shale, gradually raising the temperature of the shale toward that of the injected gas. The kerogen is converted to bitumen and finally to a low pour point, high gravity crude oil.

Since the temperature of the natural gas is below that for thermal decomposition of the mineral carbonates in the oil shale, little CO2 is produced. The natural gas is compatible with the oil, being soluble in it; this aids in the penetration of the formation by the natural gas and in the heat transfer. Since the heating gas is completely free from oxygen, no oxidation induced polymerization of the oil occurs.

Prior to the field experiment, oil shale cores from the Piceance Creek Basin were heated in a natural gas stream under two conditions. Some experiments were run at a gas pressure of 300 lb/sq. inch.
New DAP Mud System Shows Promise for Rocky Mountain Environmentally Sensitive Areas
Authors: Vesely D. P.
Published: December 2007

The introduction of new polymers such as partially hydrolized polyacrylamides (PHPA) and sulfonated acrylates has led to the development of a clay-free DAP/Polymer system. The DAP/Polymer system can be used in place of KCL/Polymer in the Rockies to achieve nearly the same shale stability and has some distinct advantages as compared to KCL/Polymer muds: DAP muds are more enviornmentally acceptable.DAP muds are less corrosive.DAP muds have resistivities nearer to fresh water, facilitating log interpretation in some instances.
Predicting Power Cost and its Role in ESP Economics
Authors: Pankratz R. E. , Wilson B. L.
Published: December 2007

With the current pressure on profitability, the economics of oil production are being closely scrutinized by most producers. This paper develops a method for estimating the power cost for electrical submersible pumping systems (ESP's) and views the role of power cost in the overall picture of economics for this type of artificial lift. To validate the procedure that is used, the calculations have been compared to actual data taken from field tests of operating ESP's.

This paper is directed toward the Engineer who is responsible for the selection of artificial lift equipment. To increase the utility of the method, it uses only data published by the equipment manufacturer and well established calculating routines.

The total economic picture of artificial lift would have to include many factors which are beyond the scope of this paper. This paper will limit itself to the factors that are involved in the choices an Engineer has to make in the selection of ESP's.
Application of Laplace Transformation to Elliptical Flow in Naturally Fractured Reservoirs: Part I-Theoretical Treatment
Authors: Okoye C. U. , Oyefodun A. , Matese J. J. , Hayatdavoudi A. , Ghalambor A.
Published: December 2007

This paper presents new analytical solutions to unsteady state and pseudo-steady state flow in naturally fractured reservoirs whose boundaries can better be approximated by elliptical rather than linear or radial coordinates. While elliptical flow may occur in several geometric systems, fractured reservoirs are believed to exhibit elliptical flow behavior, particularly during the transitional period. Directional permeability inherent in fractured reservoirs creates reservoir anistropy. Flow from anistropic reservoir towards a circular wellbore will be elliptical rather than radial.

In this study the pressure pattern of naturally fractured reservoir is considered to develop under the assumption that allows matrix to fracture cross flow to result from a diffusion mechanism of fluid transfer through the matrix. The constant rate pressure distribution equations developed in this study were coupled to skin and wellbore storage parameters.

Type curves which can be used for well test analysis were generated with results of various analytical solutions. In the second part of this study, presented in the part two paper several field pressure data were analyzed using these type curves and the results compared with those obtained from type curves generated using radial or linear model solutions.
Use of Environmentally Acceptable Invert Oil Emulsion Mud in SSB/SSPC
Authors: Hashim H.
Published: December 2007

A five well trial with Environmentally Acceptable Invert Oil Emulsion Mud (EA-IOEM) has been carried out in the Balingian area offshore Sarawak during 1985 and 1986. The trial was initiated after an unsatisfactory outcome of a field test programme with KCl/polymer muds.

Two appraisal and three development wells with planned deviation angles ranging from 45 to 58° were selected. The trial was carried out in the 12¼" and 8½" hole sections.

The objectives of the trial were to eliminate drilling, evaluation and production problems caused by poor hole conditions which were experienced in high angle wells drilled with simple water based mud (WBM).

A suitable base-oil for the trial was selected to meet the following three criteria: a high flash point, a low kinematic viscosity and a low toxicity.

The experience gained in the field trial has been successfully applied to the Erb West infill drilling programme to solve the zonal isolation and drilling problems experienced in this area with WBM.

The paper addresses the operational, petrophysical and geological aspects of the trial and includes recommendations on cost and consumption estimating.
Underwater Work by Remotely Operated Vehicles (ROV's) Technology Development and Operational Experience
Authors: Batten C. J.
Published: December 2007

This paper describes experience with respect to underwater work carried out by Remotely Operated Vehicles (ROV's) on the North West Shelf Development Project, North Rankin "A" field located 135km off the North West coast of Australia. The field is operated on behalf of the joint venturers by Woodside Offshore Petroleum Pty Ltd. Installation of the platform and trunkline was completed in 1982 and from this date all underwater work has been carried out by ROV. Typical work includes detailed pipeline and platform inspections, underwater support for the installation of gravity anchors and associated guy wires, general construction support, underwater cutting, marine fouling removal, scour protection installation and pipeline stabilisation.

Information presented in this paper is applicable to all phases of offshore oil and gas production that requires work to be done underwater e.g. exploration drilling, construction, operational inspection and maintenance. The paper describes special tooling procedures and systems developed to perform the above work. Also presented are new information and statistics associated with bulk marine fouling removal by purpose designed/bui1t remotely operated equipment.

The paper concludes that significant underwater work can be performed cost effectively without exposing men to risks associated with the underwater environment and shows that a much larger slice of the underwater work "pie" can be achieved by ROV than has previously been generally accepted.

Specific data related to time/costs associated with performance of significant aspects of the work are presented.
Reservoir Water Control Treatments Using a Non-Polymer Gelling System
Authors: Chan K. S.
Published: December 2007

A new non-polymer in-situ gelling system has been developed for reservoir water control treatments. This paper includes the results of a series of key laboratory tests in characterizing this system for practical well treatment designs.

The system comprises two to three chemicals which are readily soluble in most field mix waters and seawater. The fluid has a low viscosity close to that of the water, and can be pumped at any rate. The treatment is a simple single slug injection process using ordinary field mixing and injection equipment. In the rock formations, the injected fluid system forms a semi-solid gel which will transform into a solid phase after a time period. Typically, the treated formation permeability reduction is 50 folds or 98%.

The microscopic pore blocking efficiency as tested by core flow experiments can be correlated with the gel strength which is expressed in term of gel extrusion pressure gradient (psi/ft) as measured by a core plug test. This enables the treatment fluid penetration requirement calculations using the near wellbore pressure gradient values during the production or injection as input data instead of a blind assumption on a certain radial penetration.

Excellent fluid flow selectivity in the water-out layer has also been demonstrated by many laboratory bi-core flow experiments modelling a typical two-layer reservoir.
The Progressing Cavity Pump in Europe: Results and New Developments
Authors: Gaymard B. , Chanton E. , Puyo P.
Published: December 2007

The first part of this paper is a reminder of the principle and the design of the Progressing Cavity Pump. It recalls the Moineau principle on which the pump works, describes the various parameters which define the pump and determine its performances. It shows the configuration used for oil production and indicates the range of practical performance that can be expected.

The second part describes the results of three years of operations in Europe. It states the practical characteristics and advantages of the Progressing Cavity Pump as they have been observed and sometimes suggested by various users.

The third part deals with two recently developed pump models which broaden significantly the area of operation of the Progressing Cavity Pump:

– The first one is a large capacity pump for high productivity and/or high water cut wells. – The second one is a high pressure pump for the production of high viscosity crude.

The presentation of the high pressure pump includes a discussion of the effects of high viscosity on the pump operation and of the solutions offered to optimize this operation.