bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical Assessment and Sampling of Drilling-Fluid Reserve Pits
Authors: Wojtanowlcz Andrew K. , Field Stephen D. , Krllov Zoran , Spencer Fritz L. 
Published: December 2007

Summary
A field survey of four drilling-mud reserve pits associated with 14,000-ft [4267-m] exploratory wells onshore U.S. gulf coast is presented. Each pit was sampled with a three-dimensional grid base with 80 to 100 samples per pit. The samples were analyzed for solids, liquids, rheological properties, and such contaminants as oil, chlorides, and metals (Cr, Pb, Ba, and Zn). The statistical data were used to develop the recommended pit sampling procedure, which included the best sampling depth and the optimum number of samples to assess the metal toxicity within a given accuracy. Two example calculations are also presented.
Improved Detectability of Blowing Wells
Authors: de Lange John I. , Darling Toby J. 
Published: December 2007

Summary
Relief wells to kill a blowing well can be drilled more efficiently if the casing joints of a blowing well are magnetized to improve the detection range of magnetostatic homing-in tools. This method was proved in field tests, and a considerable increase in the detection range of such magnetostatic tools as the Magrange™ and measurement-while-drilling (MWD) tools (from 50 to 100 ft [15 to 30 m]) was established.
Pressure Behavior of Layered and Dual-Porosity Reservoirs in the Presence of Wellbore Effects
Authors: Olarewaju J. S. , Lee W. J. 
Published: December 2007

Summary
This paper presents a new analytical solution for pressure-transient tests from layered reservoirs with or without crossflow. The analytical solution is for modeling layered-reservoir systems with unsteady-state or pseudosteady interlayer crossflow, commingled or stratified flow, and even dual-porosity systems with pseudosteady matrix-to-fracture transfer in the presence of skin, wellbore storage, and phase segregation.
Microbial-Enhanced Waterflooding: Mink Unit Project
Authors: Bryant Rebecca S. , Burchfield Thomas E. , Dennis D. M. , Hitzman D. O. 
Published: December 2007

Summary
A microbial-enhanced waterflooding field project is being conducted in the Mink Unit of the Delaware-Childers field in Nowata County, OK. A microbial formulation was injected into four injection wells and has been followed by periodic injections of molasses as nutrient. Laboratory and field procedures that were used to design the test are described. Improvements in both oil production rate and WOR's have been observed.
A New Method for Estimating the Dykstra-Parsons Coefficient To Characterize Reservoir Heterogeneity
Authors: Jensen Jerry L. , Currie Iain D. 
Published: December 2007

SummaryWe propose a new method to estimate the Dykstra-Parsons coefficient that leads to a more statistically reliable indication of the true heterogeneity level. The new method extracts more information from the data to produce an estimate that gives half the error of the traditional approach. Several cases are considered to demonstrate the effects of more reliable Dykstra-Parsons coefficients on predicted reservoir performance.
Tracer- and Pressure-Test Analysis for Characterization of Areally Heterogeneous Reservoirs
Authors: Mishra Srikanta , Brigham William E. , Orr Franklin M. 
Published: December 2007

Summary
This study compares simulated well-to-well tracer and transient pressure tests in a quadrant of a repeated five-spot with spatial variations in permeability. Single-layer heterogeneous media with an autocorrelated and log-normal permeability distribution are generated with a stochastic moving-average method. Finite-difference simulation of pressure behavior in these systems indicates that the geometric mean of effective permeabilities around injection and production wells is a good approximation for the steady-state interwell permeability. A dimensionless permeability difference, defined in terms of these quantities, correlates with a heterogeneity index, defined as the product of permeability variance and a dimensionless correlation length scale.
Tracer flow is simulated with a particle-tracking procedure. Simulations show that when the heterogeneity index is small, tracer response can be matched with solutions of the convection-dispersion equation with a constant dispersivity that is proportional to the heterogeneity index. For larger values of this index, preferential flow paths are created that cause tracer-breakthrough curves to behave as though they result from flow in a layered system. A method is proposed to estimate the heterogeneity index from pressure-test data and thus to predict the nature of the tracer response qualitatively.
Displacement Mechanism and Water Shielding Phenomena for a Rich-Gas/Crude-Oil System
Authors: Tiffin D. L. , Sebastian H. M. , Bergman D. F. 
Published: December 2007

Summary
This paper presents an experimental study involving a series of hydrocarbon miscible displacements of a crude oil. Compositional analyses of both flowing effluent phases show that most of the oil was recovered by the condensing-drive mechanism. High mobile water saturations in the highly water-wet Berea cores used led to the same oil-trapping phenomena as noted for CO2 displacements.
Appraisal of the Use of Polymer Injection To Suppress Aquifer Influx and To Improve Volumetric Sweep in a Viscous Oil Reservoir
Authors: Hughes D. S. , Teeuw D. , Cottrell C. W. , Tollas J. M. 
Published: December 2007

SummaryA novel way to use polymer injection to suppress the influx of a strong edge aquifer in a shallow, dipping reservoir containing a 15-cp [15-mPa·s] oil and thereby to improve volumetric sweep has been investigated. Experimental studies were undertaken to determine the appropriate polymer properties, which were then used in simulation studies to establish oil-recovery profiles.
Imaging Fluid Saturation Development in Long-Core Flood Displacements
Authors: Graue Arne , Kolltveit Kristofer , Lien Jan. R. , Skauge Arne 
Published: December 2007

Summary
Fluid saturation development in long-core flood experiments is investigated. Information on 1D fluid saturation distributions is obtained by labeling the fluid phases with nuclear tracers and detecting radiation with a movable detector. Various flood experiments were done on 2.5-ft [76-cm] -long sandstone cores. In miscible displacements where radioactive brine is displacing inactive brine, dispersion and ion adsorption are evaluated. Imaging saturation profiles during drainages and waterfloods gives information on saturation-front velocity and time development of local saturation variations. Experimental results are compared with numerical results from a 1D front-tracking black-oil simulator that incorporated inhomogeneities and capillary effects. Surfactant floods were investigated to test the applicability for EOR studies further.
Batch-Mix Fracturing: An Effective Method of Stimulating Moderate-Permeability Reservoirs
Authors: Cramer David D. , Songer Mark A. 
Published: December 2007

SummaryThis paper evaluates batch-mix-fracturing (BMF) applications in moderate-permeability reservoirs. Specialized BMF equipment provides a reliable means of creating short, highly conductive fractures. BMF efforts have been improved by effective treatment design and the use of a computer-driven fracture simulator. A case study of fracture treatments in a Wyoming oil reservoir indicates that the BMF technique can provide results superior to conventional methods with continuous-mix equipment.
Borehole Instability in the Western Canadian Overthrust Belt
Authors: Woodland David C. 
Published: December 2007

Summary
Borehole instability is primarily a rock mechanics problem. Regional earth stresses and typical rock strengths are used to explain the widespread nature of irregularly shaped, fragile boreholes in the western Canadian Overthrust Belt (foothills). Drilling fluids and practices are investigated with a rock mechanics model of borehole failure. Although drilling practices can significantly affect problems associated with borehole wall failure, they are not the primary cause.
One-Trip, Multizone Gravel-Packing Technique for Low-Pressure, Shallow Wells
Authors: Welrich John B. , Zaleski Theodore E. , Tyler Steve L. 
Published: December 2007

Summary
This paper describes a one-trip, multizone gravel-packing technique designed for use in short-zoned, shallow, low-pressure wells. The system, which allows several zones to be completed with a single gravel-pack assembly, has been adapted for use in both standard and thermal applications.
Formation Damage From Acid Treatments
Authors: Bryant Steven L. , Buller David C. 
Published: December 2007

Summary
Well treatments with only HCl are potentially damaging in formations that contain aluminosilicate minerals (clays, feldspars, and micas) because HCl reacts significantly with aluminosilicates, leaching aluminum and forming hydrated silica. Fluid flow past leached mineral particles liberates mineral fragments and amorphous silica within the pore network. These fines can block pore throats, reducing the rock permeability. Both field data and reservoir-condition coreflood test results are consistent with this chemical reaction and permeability impairment mechanism. The average permeability reduction in our corefloods was 35%.
An Innovative Single-Completion Design With Y-Block and ESP for Multiple Reservoirs
Authors: Moradl Shirall C. 
Published: December 2007

Summary
This paper describes an effective well-completion program initiated in five recently developed fields in the northwest Java Sea. Because these fields contain multiple reservoirs, an innovative downhole completion system was implemented to obtain optimum production and operational flexibility at minimal cost.
Depending on the number of reservoirs, as many as five sealbore-retrievable packers were set in a well and then individually tested to ensure isolation. This system allows us to (1) perforate different reservoirs selectively; (2) isolate, acidize, test, and monitor separate zones; (3) produce a well by natural flow initially or by electric submersible pump (ESP); (4) commingle zones; (5) run pressure surveys and production logs; (6) manipulate and eliminate water/gas producing zone(s); (7) service the ESP as required without fluid loss to the formation; and (8) protect the downhole equipment from corrosive gases by continuous inhibition. Major downhole work is performed inexpensively by wireline and/or snubbing units.
After completion, three different reservoir lithologies (sandstone, limestone, and metamorphic) were isolated, stimulated, tested, monitored, and selectively produced. To date, more than 90 oil wells with as many as three different lithologies and 20 separate formations have been completed successfully. Since this paper was presented, about 20 more platforms have been completed (nine wells per platform) with this system. This innovative completion system allows optimal production of multiple-reservoir fields at minimal cost.
The Effect of Carboxylic Acid Anions on the Stability of Framework Mineral Grains in Petroleum Reservoirs
Authors: MacGowan Donald B. , Surdam Ronald C. , Ewing Richard E. 
Published: December 2007

Summary
This paper presents experimental and empirical evidence to show that carboxylic acid anions (CAA's) are a major diagenetic control on first-cycle basins in Jurassic-to-Pleistocene reservoirs in the 80-to-120°C thermal window.
Acid-Soluble Magnesia Cement: New Applications in Completion and Workover Operations
Authors: Sweatman Ronald E. , Scogglns W. Chrys 
Published: December 2007

Summary
Acid-soluble magnesia cement (MC) was used in production zones to plug perforations temporarily to reduce brine losses during completion and workover operations. This has resulted in substantial savings for operators. The cement has also been used to reduce potential formation damage. This paper describes some of the characteristics of the cement, field applications, and results.
Interpretation of ADEPT Logs in the Presence of Mudcakes
Authors: Freedman Robert , Grove Gregory P. 
Published: December 2007

Summary
Results of a theoretical investigation of mudcake effects on the high-frequency, dielectric, adaptable electromagnetic propagation tool (ADEPTSM) are presented. Charts are presented that correct log data for mudcake effects, thus giving true formation travel times and attenuations. Mudcake effects on the ADEPT interpretation are illustrated with data from a shaly sand well.
Dynamic Measurements of Beam-Pump Parameters
Authors: Lea J. F. , Bowen J. F. 
Published: December 2007

Summary
Measurements of nine electrical and mechanical parameters were made on conventional and special-geometry units during operation. All quantities were measured simultaneously and computer-recorded for a variety of pumping conditions. Using this data, we compared measured dynamic gearbox torques with calculated values, illustrating how calculation techniques model dynamically measured data. Calculated efficiencies indicating losses through the units from polished rod to the gearbox are shown to be necessary for adjusting gearbox torque calculations to measured values. Also, torque/speed curves are shown at the motor sheave. These data are corrected for inertial effects and plotted vs. motor manufacturers’ published curves. Possibilities for future work incorporating these measurement techniques while the unit is in operation were discussed. In general, the data show how dynamically measured beam-pump data compare with conventional calculation techniques.
Efficiency and Pressure Recovery in Hydraulic Jet Pumping of Two-Phase Gas/Liquid Mixtures
Authors: Jiao Baohua , Blais Roger N. , Schmidt Zellmir 
Published: December 2007

Summary
Hydraulic jet pumping of gas/liquid mixtures was studied experimentally, and a mathematical model is proposed to extend the standard single-phase model for predicting efficiency and pressure recovery to suction fluids with gas/liquid ratios up to 2, 200 scf/STB. The experimental program comprises 616 low-pressure tests in a plastic model pump designed for flow visualization and measurement of pressure profile along the throat and diffuser, and 373 high-pressure tests on a stock pump. For the high-pressure tests, power fluid was supplied at 200 to 3, 000 psi and at 200 to 860 B/D; air was supplied from 0 to 185 Mscf/D. Discharge pressures ranged from 800 to 2, 000 psi.
The mathematical model extends a previous model that describes single-phase performance from mass and energy conservation. The empirical loss coefficients for the nozzle and throat/diffuser are replaced by a nondimensional expression that varies as three dimensionless parameters: nozzle-to-throat area ratio, discharge-to-power-fluid pressure ratio, and air/water ratio (which usually is in conventional units of cubic feet per stock-tank barrel but is, of course, basically dimensionless). The loss coefficient for the nozzle is constant, but for the throat/diffuser it is a constant plus a product of a constant times the three parameters, each to a power.
Compared with the standard model, which always overpredicts pressure recovery and thus efficiency, the new model reduces the standard error of the estimate to 18% of its former value.
Dual Leakoff Behavior in Hydraulic Fracturing of Tight, Lenticular Gas Sands
Authors: Warpinski Norman R. 
Published: December 2007

SummaryStimulation experiments conducted in anisotropic, naturally fractured, tight, lenticular gas sandstones have shown the existence of a dual-leakoff phenomenon. Below a threshold pressure, the leakoff coefficient is very low and fluids are very efficient. Above the threshold, leakoff increases by a factor of 50, slurries dehydrate rapidly, and screenouts occur in minutes. The leakoff has been shown to be controllable to some extent with 100-mesh sand. Results of three stimulation experiments are presented, including a treatment that screened out, a minifracture experiment that showed the effectiveness of 100-mesh sand, and a final successful stimulation.
Experimental Study of Cocurrent and Countercurrent Flows in Natural Porous Media
Authors: Bourbiaux Bernard J. , Kalaydjian François J. 
Published: December 2007

Summary
Flow experiments involving cocurrent and countercurrent spontaneous water/oil imbibition were performed on the same laterally coated sample of a natural porous medium with local saturation measurements and various boundary conditions. The experiments with countercurrent imbibition showed slower oil recovery, a smoother water/oil front, and slightly lower ultimate oil recovery than those with predominantly cocurrent imbibition. Numerical simulations revealed that the relative permeabilities that enabled good prediction of countercurrent oil recovery rate are about 30% less than the conventional cocurrent relative permeabilities at a given water saturation. Viscous coupling is assumed to be the origin of this difference. A new formulation of Darcy equations that uses a matrix of mobilities was found to be in qualitative agreement with experimental results.
A New Iterative Solution Technique for Reservoir Simulation Equations on Locally Refined Grids
Authors: Brand Clemens W. , Heinemann Zoltan E. 
Published: December 2007

Summary
This paper presents an incomplete LU (ILU) factorization technique coupled with generalized conjugate-gradient acceleration especially designed for linear equations resulting from locally refined grids. The factorization is based on a special ordering scheme. This repeated red/black (RRB) ordering can cope naturally with grid irregularities introduced by local refinement. The scheme is also very effective on regular grids, where the condition number (a measure of the convergence rate) of the preconditioned linear system increases asymptotically with the number of gridblocks more slowly than it does for conventional ILU preconditionings. For large linear systems, fewer iterations are needed to reach convergence. This makes the method highly competitive compared with other techniques even on regular grids, although the new ordering scheme requires more data handling than standard orderings. Results for several idealized test cases [implicit-pressure, explicit-saturation (LMPES) equations] show the new method to be faster than standard iterative methods.
A Control-Volume, Finite-Element Method for Local Mesh Refinement in Thermal Reservoir Simulation
Authors: Forsyth Peter A. 
Published: December 2007

Summary
This paper describes a control-volume, finite-element technique for coupling coarse grids with local fine meshes. The pressure is treated in a finite-element manner, while the mobility terms are upstream weighted in the usual way. This requires identification of the cell volumes and edges that are consistent with the linear finite-element discretization of the pressure. To ensure that the pressure equation yields an M matrix, various conditions are required for the type of triangulation allowed. Because the form of the equations is similar to the usual finite-difference discretization, standard techniques can be used to solve the Jacobian. The local mesh-refinement method is demonstrated on some thermal reservoir simulation problems, and computational results are presented. Significant savings in execution times are obtained while predictions similar to global fine-mesh runs are given.
Effect of Rheology on Gel Placement
Authors: Seright R. S. 
Published: December 2007

SummaryThis study investigates whether rheology can be exploited to eliminate the need for zone isolation during gel placement. Eight different Theological models were used to represent the properties of existing non-Newtonian gelling agents. Gel placement was examined in linear and radial parallel corefloods and in fractured and unfractured injection wells. The analysis indicates that, compared with water-like gelling agents, existing non-Newtonian gelling agents will not reduce the need for zone isolation during gel placement in radial-flow systems.
Re-Formation of Xanthan/Chromium Gels After Shear Degradation
Authors: Tsau J. -S. , Liang J. -T. , Hill A. D. , Sepehrnoori Kamy 
Published: December 2007

SummaryStudies were conducted on the re-formability of xanthan-gum/chromium gels that have been degraded by shear. The re-gelation study of xanthan/chromium gels showed that gels that have been sheared take longer to re-form than to gel initially and that the original gel strength often was not recovered after shearing. The weaker the gel at the time of shearing, the more likely it is that it will obtain the ultimate strength of an unsheared gel of the same formulation.
Well-Conditioning Effects on Bubblepoint Pressure of Fluid Samples From Solution-Gas-Drive Reservoirs
Authors: Peres Alvaro M. M. , Macias-Chapa Luis , Serra Kelsen V. , Reynolds Albert C. 
Published: December 2007

Summary
This work considers the determination of the initial or average reservoir bubblepoint pressure from a fluid sample obtained from a well producing a solution-gas-drive reservoir. It is shown that standard API recommended well-conditioning procedures (rate reductions) for obtaining a single-phase (liquid) bottomhole fluid sample do not always redissolve all free gas. Thus, it is not always possible to obtain a single-phase liquid (oil) bottomhole fluid sample that has a bubblepoint pressure equal to the initial or average reservoir bubblepoint pressure. Moreover, monitoring the producing GOR and bottomhole pressure does not always reliably indicate whether two-phase (oil and gas) or single-phase (oil) flow is prevalent in the near-wellbore region. Contrary to current opinion, it is shown that recombination of surface samples of oil and gas from the producing GOR usually yields reliable estimates of average reservoir bubblepoint pressure.
Uplifts and Tilts at Earth's Surface Induced by Pressure Transients From Hydraulic Fractures
Authors: Palmer Ian D. 
Published: December 2007

Summary
The pressure transient that spreads through the formation during and after a hydraulic fracture treatment pressurizes the formation and induces a certain "swelling." This swelling and the accompanying uplift at the earth's surface can be estimated with poroelastic theory. The uplift may produce a significant signal in tiltmeter devices placed at the surface. Six fracturing treatments in liquid-saturated reservoirs, all with tiltmeters to diagnose the fractures, were analyzed. In five cases, routine tiltmeter analysis postulated a horizontal fracture component (in the remaining case, a near-vertical fracture of dip 70 to 85° probably could also be interpreted by a vertical fracture with a subsidiary horizontal component). In three treatments, however, theoretical tilts calculated from the pressure transient can account for the magnitude of the tiltmeter signals, which had previously been explained by a horizontal fracture component. This result is important because the formation swelling and surface uplift associated with the pressure transient from a hydraulic fracture treatment are not usually deconvolved from the raw tiltmeter signals before their interpretation in terms of hydraulic fracture geometry. In some cases, this may be necessary. Otherwise, the shape/size of inferred horizontal and vertical fracture components may be in error; i.e., neglect of the pressure-transient effect may cause overestimation of the size of the horizontal fracture component. At worst, neglecting the pressure-transient effect may result in an inferred horizontal fracture component where one does not actually exist.
Performance of Horizontal Wells Subject to Bottomwater Drive
Authors: Ozkan Erdal , Raghavan Rajagopal 
Published: December 2007

SummaryThis paper discusses the performance of a horizontal well subject to bottomwater drive and delineates conditions under which this completion mode is more appropriate. Information presented will enable the engineer to decide what productivity improvements may be expected from horizontal-well completions. The productivities of horizontal wells operating under bottomwater drive are discussed in terms of displacement efficiencies. Results and the discussions are also applicable to oil production by gas-cap drive.