bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of Acid Fracturing
Authors: Lo K. K. , Dean R. H. 
Published: December 2007

Summary
The paper presents a theoretical framework for modeling acid fracturing stimulations. Starting from the fundamental equations of fluid mechanics, fracture mechanics, convection, and diffusion, the paper outlines the steps necessary to derive simplified equations for an acid fracturing model. Unlike some existing models, the coupled problem of fracture geometry, acid transport, and diffusion is solved simultaneously in this paper. Although an infinite reaction rate is assumed in the solution of the problem, an empirical correlation is used to account partially for finite reaction rates. Errors in the governing equations of some of the existing models are identified. To assess the accuracy of the approximations used in the present model, exact solutions are used for comparison. Predictions from the present model are compared with a model in the literature, and the results are found to be in reasonable agreement. As in all existing acid fracturing models, not all the phenomena of the acid fracturing process have been incorporated into the present model. Nevertheless, the present model is improved over existing models because it is derived from fundamental equations and thus forms a basis from which further improvements can be made.
Lagrangian Formulation for Penny-Shaped and Perkins-Kern Geometry Models
Authors: Lee W. S. 
Published: December 2007

SummaryBasic theories for vertical penny-shaped and Perkins-Kern (PK) geometry models have been developed with a Lagrangian formulation combined with a virtual-work analysis. The Lagrangian formulation yields a pair of nonlinear equations in Rf or Lf and bf, the fracture radius or length and half-width. By introduction of a virtual-work analysis, a simple equation is obtained that can be solved numerically. This equation is written in a form that can be used to determine fracture geometry when the fluid-loss coefficient of the fracturing fluid is known. Also, this equation, coupled with a material-balance equation after shut-in, can be used to analyze pressure-decline data after shut-in to determine the effective fluid-loss coefficient and fracture geometry.Geometry prediction of the new theory agrees well with other methods for the same models. A unique advantage of this approach, however, is that the geometry estimated from prefracturing design is consistent with the geometry determined from the pressure-decline analysis. Thus, it allows the engineers in the field to predict precisely the amount of fracturing fluid required for a designed fracture radius or length in a full-scale treatment from information gained in a minifracture treatment.
The EMSU Waterflood Project: A Case History of Infill Drilling, Completions, and Workovers
Authors: Mitchell R. K. , Salvo G. S. 
Published: December 2007

Summary
The Eunice Monument South Unit (EMSU) waterflood project is a large-scale (354 wells) example of implementing a waterflood in a highly depleted reservoir. Because of the maturity of this field (&gt;50 years), several problems were encountered, such as drilling depleted intervals, corroded wellbores, and stimulating depleted and scaled-off formations. This paper discusses procedures to deal with these problems. Other topics discussed include infill drilling techniques, drilling and completion of high-volume water-supply wells, use of air/mist in drilling and deepenings, and water/CO2 injection equipment. By using existing techniques and implementing new ideas, we continually cut costs throughout the life of the project. Operations were improved through continuity, implementation and analysis of new techniques, and good communications. All improvements are documented with field results and show how continual monitoring and adjustments in operations can lead to an operationally efficient, cost-effective project.
Case History of an Ultradeep Disposal Well in Western Colorado
Authors: Flak Larry H. , Brown John J. 
Published: December 2007

SUMMARY
Between Dec. 1986 and Dec. 1988, the U.S. Bureau of Reclamation drilled, tested, and completed the world's deepest disposal well. The well will be used to dispose of brine that currently seeps into the Dolores River. This natural brine spring is the largest point source of salt contamination in the Colorado River system.
Measurement of Molecular Weight Distribution of Polyacrylamides in Core Effluents
Authors: He Qingong , Young Teng-Shau , Willhite G. Paul , Green Don W. 
Published: December 2007

Summary
A procedure to measure the molecular-weight (MW) and size distributions of polymers in core effluents by size-exclusion chromatography (SEC) and low-angle laser-light scattering (LALLS) was used to analyze Berea core effluent samples containing either a hydrolyzed or unhydrolyzed Polyacrylamide (PAAM). The average MW's of the PAAM's were measured with a precision better than ±5% at a 95% confidence level. For both PAAM's, the polymer in an early effluent sample after breakthrough had a narrower MW distribution and fewer low-MW molecules than the injected polymer. This led to a higher weight-averaged MW, Mw, for the early effluent than for the injected polymer. The effluent Mw decreased with increasing PV of polymer solution injected and approached the injected polymer's Mw after a large throughput. The results of the MW distribution measurements, which suggested a relatively large inaccessible PV for larger polymer molecules, are discussed in terms of steric-exclusion effects and dependence of retention rate on polymer size.
Use off Entrainers in Improving Mobility Control of Supercritical CO2
Authors: Llave Fellciano M. , Chung Frank T-H. , Burchfield Thomas E. 
Published: December 2007

Summary
The use of entrainers (cosolvents) to improve CO2 mobility control for EOR was investigated. The cosolvent serves as a miscible additive that modifies the phase behavior of supercritical solvents and enhances the solubility of crude oil components in the CO2-rich phase. The presence of the cosolvent increases the viscosity and density of the gas phase. The improvement in supercritical extraction power and enhancement of bulk fluid properties result in improved mobility ratios.
Tertiary Application of a Hydrocarbon Miscible Flood: Rainbow Keg River "B" Pool
Authors: Nagel Raymond G. , Hunter Brian E. , Peggs Jonathan K. , Fong David K. , Mazzocchi Enrico 
Published: December 2007

Summary
The Rainbow Keg River "B" pool EOR scheme calls for placement of a 12% (net after recycle) -original-HCPV miscible bank in the crestal region of the pool. This bank will be chased vertically downward with more than 1 PV of dry gas. The injected solvent and chase gas will push the oil/water contact (OWC) downward as the previously injected water is produced. A tertiary oil bank will be formed in the region previously occupied by the water. This paper reports tertiary flood performance, results of the 1987 reservoir simulation study, and the operational strategy and problems encountered in monitoring the flood. The well-completion technique implemented to operate the flood is described, and the scheme economics is reviewed. Performance of the tertiary flood to date is encouraging.
Interpretation of Temperature Observations From a Cyclic-Steam/ In-Situ-Combustion Project
Authors: Nzekwu Ben I. , Hallam Richard J. , Williams G. J. J. 
Published: December 2007

Summary
Data collected at 10 temperature observation wells were analyzed to evaluate the implementation of a combined process of cyclic steam stimulation followed by pressure-up/blowdown combustion for the in-situ recovery of bitumen. The temperature profiles at four observation wells, along the northeast/southwest fracture plane (on-trend direction), confirmed the height and orientation of the vertical fractures during cyclic steam stimulation. Six off-trend wells indicated that the heat transfer away from the fracture plane was predominantly conductive, with varying amounts of convective flow. During the in-situ combustion phase, frontal temperatures &gt; 2, 200°F [1200°C] were detected. Data also indicated that the vertical location of the combustion front can be controlled by either gravity or mobility effects. The off-trend heating was improved as a result of higher convective heat fluxes.
Mathematical Modeling of High-pH Chemical Flooding
Authors: Bhuyan Debojit , Lake Larry W. , Pope Gary A. 
Published: December 2007

SummaryThis paper describes a generalized compositional reservoir simulator for high-pH chemical flooding processes. This simulator combines the reaction chemistry associated with these processes with the extensive physical- and flow-property modeling schemes of an existing micellar/polymer flood simulator, UTCHEM. Application of the model is illustrated for cases from a simple alkaline preflush to surfactant-enhanced alkaline-polymer flooding.
Carbon Isotope Analysis: A New Tool for Monitoring and Interpreting the In-Situ Combustion Process
Authors: Hallam Richard J. , Moore R. Gordon , Krouse H. R. , Bennion Douglas W. 
Published: December 2007

Summary
This paper investigates the use of carbon isotope analysis for monitoring and interpreting responses from the in-situ combustion process. The major finding was that the type of reaction occurring at the combustion front can be distinguished by carbon isotope analyses. These reactions include the classic burning profile at the leading edge; super-wet or low-temperature combustion; a wide combustion zone with a secondary front, which is indicative of oxygen channeling; and carbonate decomposition in carbonate core material. This tool is valuable because, at times, making these interpretations without temperature data or from gas analyses alone is not possible. The study also demonstrated the feasibility of using carbon isotope data to track communication among injection and production wells.
Constant-Internal-Phase Design Improves Stimulation Results
Authors: Harris Phillip C. , Klebenow Donald E. , Kundert D. Pat 
Published: December 2007

Summary
For several years, foam fracturing has been an excellent technique for stimulating low-pressure reservoirs. Conventional foam treatments, however, have been inconsistent in placing high sand concentrations and often reached a pressure limitation, which prematurely terminated the treatment.
A new design approach to foam fracturing, the constant-internal-phase technique, has overcome previous sand limitations and has allowed treatments to be pumped with less severe pressure fluctuations. This approach treats all internal phases (gas, liquid, or solid) the same and recognizes the similarities in behavior among foams, emulsions, and slurries. A fluid's bulk viscosity increases as the total internal-phase fraction increases, particularly at high internal-phase ratios. The constant-internal-phase approach has produced more predictable wellhead treating pressures (WHTP's), used less hydraulic horsepower, and virtually eliminated premature job termination owing to pressure limitations.
Gravel Packing for the Duri Steamflood
Authors: Shryock Steven G. , Ahmad Syafriwal , Meloy James M. , Kent John W. 
Published: December 2007

Summary
The multibillion-barrel Duri field is being developed for steamflooding. The completion designs have evolved over 20 years of huff 'n' puff steaming and pilot steamflooding. A reduced-density slurry-packing method is being applied in single- and dual-zone, openhole gravel packs (OHGP's) and cased-hole gravel packs (CHGP's) to complete shallow, underpressured formation sands. Continuing problems include lost circulation, loss of pack upon steaming, and lower-than-expected productivity. Recent improvements have been made in well preparation, fluid cleanliness, liner design, and gravel-placement techniques. When lost circulation or unstable hole conditions are encountered, foam has been used for drilling, underreaming, and gravel packing. This case history demonstrates the importance of well-completion details in obtaining sand control with high productivity for a large steamflood.
Real-Gas Effects in the Expansibility Factor for Subsonic Differential-Pressure Flowmeters at High Pressure
Authors: Finjord Jan 
Published: December 2007

Summary
Real-gas corrections in the expansibility factor are expressed by an equation of state (EOS). A virial EOS is introduced, with low-order virial coefficients calculated from a cubic EOS. The approach is composition-independent. EOS-dependent cancellations between real-gas effects are revealed. The current Intl. Organization for Standardization (ISO) standard is not always reliable for high-accuracy orifice measurements of gases with arbitrary composition.
Inhibition of Barium Sulfate Deposition by Polycarboxylates of Various Molecular Structures
Authors: van dor Leeden M. C. , van Rosmalen G. M. 
Published: December 2007

Summary
To establish a relationship between the molecular structure of polycarboxylates and their growth-retarding influence on barium sulfate, seeded-suspension-growth experiments were performed at various inhibitor concentrations and pH values. Two types of polycarboxylates with a molecular structure based on either polyacrylic or maleic acid were studied. The molecular structures of these compounds were varied by partial substitution with monomers containing hydroxyl, amide, and sulfonic acid, as well as hydrophobic groups. Hydrophobic groups are detrimental to good inhibitor performance, whereas the introduction of OH, NH2, or SO3H groups presents opportunities to enhance the inhibitor effectiveness. The sequence in performance of the compounds on barium sulfate was compared with the sequence formerly obtained for calcium sulfate dihydrate.
A Straight-Line Approach To Determine the Distance to Barriers
Authors: Duong Anh N. 
Published: December 2007

Summary
The pressure response for a well located near a linear impermeable barrier is differentiated and rearranged so that a linear relation between the two variables of the pressure-derivative group and 1/t is obtained. A plot of log|2.303p′t/m − 1| vs. 1/í yields a straight line with a fixed intercept and a slope proportional to the square of the distance to the barrier (or boundary). The straight-line approach is also extended to apply to two perpendicular no-flow barriers and to buildup test data. The advantage of the approach presented here is that pressure data can be analyzed to determine the distance to barriers even if the late-time semilog straight line whose slope is twice or four times the slope of the first semilog straight line is not reached. A field example is included for illustration.
Tight Carbonate Intervals: Vertical Permeability and Threshold Pressure Estimation Models
Authors: Mitrl K. T. , Abed A. -F. A. -R. 
Published: December 2007

SummaryThis paper presents a synergetic study of dense stylolitic intervals within Lower Cretaceous heterogeneous (multilayer) carbonate reservoirs. A new method for characterizing vertical permeability of the dense limestone intervals is developed on the basis of a semiempirical lumped-parameter model. Empirical extension of the method yielded estimates of threshold pressures. The adopted reservoir-description approach provides a purely explicit and interconsistent framework that is especially useful as basic input for detailed full-field simulation-study applications. The concept of excess interfacial tension (IFT) is introduced, and a generalized relationship is proposed for the equivalency of capillary pressure measurements with different fluid pairs by use of a correction term to the classic ratio of IFT's that becomes significant in very-low-permeability media.
The Zakum Telesystem: An Application of Large-Scale SCADA Systems to a Major Offshore Oil Field
Authors: Kahoul Jamel M. 
Published: December 2007

Summary
Various types of supervisory-control and data-acquisition (SCADA) systems are in use in oil fields around the world, assisting field personnel in maintaining safe and profitable operations. The Upper Zakum field, one of the largest offshore fields, requires a far more extensive SCADA system with higher levels of distribution than generally needed. This paper outlines the environment and extent of the field, emphasizing the need for unmanned operation and the evolution of the Zakum telesystem to meet the special requirements. Specification and predesign phases are shown to be vitally important parts of the project, in both assessing the telesystem's final extent and predicting what the field operators need to control the field. The telesystem implementation is described in detail, including system architecture, operator facilities, hardware and software considerations, and various interfaces with other systems. The problems encountered during the project and their solutions are discussed, and conclusions are drawn for future projects. The need for the highest available level of technology and the likely consequences of compromising this need because of cost considerations are also discussed. Finally, recommendations are proposed for future selection of large-scale SCADA systems.
Well-Test Analysis Following a Closed-Fracture Acidizing Treatment
Authors: Soliman Mohamed Y. , Hunt James L. , Daneshi Tahereh 
Published: December 2007

Summary
A new model representing fluid flow in a reservoir treated with closed-fracture acidizing (CFA) is presented. The model is characterized by a low-conductivity fracture (representing the closed fracture) and highly conductive wormholes (owing to acid flow). Application of the model to pressure-transient data analysis following a CFA treatment is presented through a field example.
Procedures and Practices of Dual-Completion Design in Abu Dhabi
Authors: Gabert Robert F. , Ghneim George J. 
Published: December 2007

Summary
The first generation of dual completions run by Abu Dhabi Marine Operating Co. (ADMA-OPCO) had a 7-in. liner and 9⅝-in. casing/tubing annulus as an independent string. Modifications were introduced later to protect the casing and the liner top and to optimize tubing sizes to suit reservoir monitoring and production/injection requirements. This optimization was accomplished with full dual tubing strings ("tubular-flow" completions) or a combination of dual tubing strings and 7-in. liner/tubing annulus ("modified-tubular-flow" completions). This paper discusses equipment selection and solutions to operational problems. The modified-tubular-flow completions were easier to run and to recover than the tubular-flow completions.
Quantitative Determination of the Mechanical Properties of Shales
Authors: Steiger Ronald P. , Leung Peter K. 
Published: December 2007

Summary
Shales make up more than 75% of drilled formations and cause at least 90% of wellbore-stability problems. Physical measurements of shale properties are required to develop realistic constitutive relationships and to understand and define shale strength and behavior under downhole conditions. Quantitative shale-strength data are needed to improve wellbore-stability model predictions. This paper describes a research test program to determine the mechanical properties of different classes of shales and to build a database on their characteristics and mechanical behavior. Shale samples from undisturbed block samples were prepared under controlled conditions. Mechanical test techniques were developed to measure effective-stress/strain properties accurately for shales. The tests require a heavy-duty, triaxial test load frame and other specially designed equipment to obtain precise pore pressure measurements. During the tests, pore pressure, stresses, and strains were monitored accurately by an automatic data-acquisition system. The test techniques described can be used to test shales with different characteristics: soft, hard, brittle, plastic, etc. On the basis of results of several shale tests, high-quality, effective-stress/strain data and failure criteria (shale strength relationships) can be obtained routinely.
Attenuation of Casing Cemented With Conventional and Expanding Cements Across Heavy-Oil and Sandstone Formations
Authors: Beirute R. M. , Wilson M. A. , Sabins F. L. 
Published: December 2007

Summary
Studies were conducted with a large-scale displacement model containing manmade tar and competent (hard) manmade sandstone formations. This paper investigates the cement placement process and the acoustic response with standard logging tools. This investigation revealed that the formations behind the cement make a significant contribution to the pipe-attenuation rate. The large-scale acoustic experiments indicate that lower pipe-attenuation-rate levels are measured when tar formations are cemented. This occurs even with the same type of cement and the same annular clearances. The tests suggest that low-attenuation-rate levels also may be measured across other low-restraint formations.
A Model for Predicting the Density of Oil-Based Muds at High Pressures and Temperatures
Authors: Peters Ekwere J. , Chenevert Martin E. , Zhang Chunhal 
Published: December 2007

Summary
A compositional material-balance model was used to predict the densities of diesel- and mineral-oil-based muds at elevated pressures and temperatures. We measured the densities of diesel oil, two mineral oils, and calcium chloride solutions from 78 to 350°F and from 0 to 15, 000 psig. The measured densities were used in an existing compositional material-balance model to predict the densities of 11- and 17-lbm/gal oil-based muds. We also measured the densities of these muds at elevated pressures and temperatures and compared them with the predicted values. The results show excellent agreement between measured and predicted densities. The experimental density data were used to predict downhole densities and static wellbore pressures for the oil-based muds. Results show that the mineral-oil muds are not only more compressible than the diesel-oil muds, but also more susceptible to thermal expansion. Therefore, all the oil-based muds tend to give essentially the same static-wellbore-pressure profile.
Re-Evaluation of the Misoible WAG Flood in the Caroline Field, Alberta
Authors: Birarda Gary S. , Dilger Chris W. , Mcintosh Ian 
Published: December 2007

Summary
Premature water breakthrough led to reassessment of a miscible water-alternating-gas (WAG) injection scheme. The reassessment involved detailed geological modeling and a reservoir simulation study. A matching of the complex reservoir history was achieved, and the economic benefits of the scheme were reaffirmed.
The Effects of Steam on the Combustion of Oil on Sand
Authors: Urban David L. , Udell Kent S. 
Published: December 2007

Summary
A simultaneous differential thermal analysis (DTA)/evolved gas analysis (EGA) system was developed to study in-situ oil-oxidation reactions. The oxidation of crude oil deposited on sand was studied, including catalysis by dissolved ionic compounds and reservoir sand materials and changes in the reaction mechanism caused by the presence of steam. The influence of steam was the most significant of these factors. In the presence of steam, the low-temperature-oxidation (LTO) exothermicity is similar to the dry case, but the oxygen consumption is dramatically reduced and, unlike the dry case, all consumed oxygen appears in the effluent carbon oxides. Participation of water and its radicals in the reaction mechanism is probably responsible for this change. These reactions should have a major influence on wet in-situ combustion.
Light Oil Recovery From Cyclic CO2 Injection: Influence of Low Pressures, Impure CO2, and Reservoir Gas
Authors: Monger T. G. , Ramos J. C. , Thomas Jacob 
Published: December 2007

Summary
This paper is a laboratory and field investigation of the CO2 huff ‘n’ puff process for the enhanced recovery of light crude oil. Cyclic CO2 displacement results with live and dead oils in watered-out Berea cores are presented. Sixty-five single-well cyclic CO2 field tests conducted in a pressure-depleted reservoir are evaluated.