bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Analysis of Large-Scale Flooding in the Fractured Spraberry Trend Area Reservoir
Authors: Barfield E.C. , Jordan J.K. , Moore W.D. 
Published: December 2007

Introduction
The Spraberry Trend oil reservoirs, producing from a very tight fractured sand, have been characterized by a rapid decline in reservoir pressure and oil producing rate and by production of only a small fraction of estimated original oil in place. Almost all original areas of development are now in the stripper stage or have been abandoned. Although it was considered unlikely that this solution gas-drive reservoir would lend itself readily to conventional methods of secondary recovery, a great deal of effort has been devoted to developing techniques which would utilize the unusual characteristics of the reservoir rock and its fracture system to increase ultimate oil recovery. A single five-spot pilot water flood was initiated in the west central portion of the Spraberry Trend Area reservoir during March, 1955. A combination analytical and numerical method employing high-speed computing equipment was utilized to analyze results of this pilot flood. With field behavior as the criterion for the analysis, orientation of the major fracture system, ratio of the permeability parallel and perpendicular to this trend, and relationship of the observed recovery from the center producing well of the pilot flood to that which might be achieved under large-scale flooding operations were determined. Information developed during analysis of the pilot water flood was then used to develop a flooding program for a 40-section area in the western portion of the field. From this work, it was concluded that the analysis procedure has considerable utility in analyzing flooding operations in a fractured reservoir and a relatively high pattern efficiency can be achieved in the area studied if the proper flooding pattern is chosen.

Attempts to Develop Recovery Techniques
The first attempt to develop a new recovery technique was a process designed by The Atlantic Refining Co. to utilize the principle of water imbibition. Laboratory work and the subsequent field trial demonstrated that water injected into the fractures could be imbibed spontaneously into the matrix rock by capillary action with the concurrent expulsion of oil into these same channels from which it could be produced by the surrounding wells. The second example of the research effort to increase oil recovery was work performed by Humble Oil and Refining Co. It was determined that with an intensive and inter-connected system of fractures, water injected into the formation could flood simultaneously a large number of matrix blocks. Water invading the matrix with the concurrent discharge of oil into the fractures would rapidly increase oil content and reduce water content of the effluent in the fractures moving toward the producing wells. To evaluate the potentialities of this type flood, a single five-spot pilot water flood was put into operation March 8, 1955.
Application of Laboratory Data in Calculating the Primary Production History of the Cisco K-1 Reservoir
Authors: Hardy William C. , McArthur B.W. 
Published: December 2007

Abstract
The purpose of this work is to show application of laboratory data in calculating solution gas-drive performance of the Cisco K–1 reservoir. Included herein is a diagram showing the graphical relationship between six variables common to all solution gas-drive mechanisms. With an iterative process one may assume existence of any of these six variables at a particular pressure and calculate the production performance likely to occur in a reservoir produced by solution gas drive.
Four unique pressure values are described at which the material balance equation alone is sufficient to predict the cumulative volumes of gas produced. Information derived from these pressure points establishes a criterion for determining compatibility of the pressure-volume-temperature (PVT) analysis of the produced crude with the gas production history.
Two averaging procedures are used to arrive at a relative permeability-saturation relationship which describes the field-wide performance.

Introduction
The Cisco K–1 reservoir is a lenticular-type sand structure lying at approximately 6,300-ft subsurface. It is located in the H. and T. C. Railroad Co. Block 97, SW 1/4 S 392 and NW 1/4 S 385, Scurry County, Tex. Correlation of data from logs indicated that the Cisco K–1 reservoir occupied approximately 2,390 acre-ft of space with a closure of from 15 to 20 ft.
Analysis of the production data indicates that the initial formation pressure and temperature were 2,450 psig and 121F, respectively. The bubble point occurred at 1,715 psig after production of 12,256 STB oil and 11,520 Mcf gas. Only traces of water have been produced since initiation of production. Successive material balance calculations from June, 1952, to June, 1957, showed that no initial gas cap or water influx has contributed to production of oil and that the Cisco K–1 reservoir originally contained approximately 1.44 X 10(6) STB of oil.
Theory and Application of Imbibition Phenomena in Recovery of Oil
Authors: Graham J.W. , Richardson J.G. 
Published: December 2007

Abstract
The purpose of this paper is to present the results of theoretical and experimental studies of water imbibition. The imbibition processes are involved in recovery of oil from stratified and fractured-matrix formations in natural water drives and water flooding. An understanding of the role of imbibition in implementing the recovery of oil from such formations is deemed essential to proper control of these reservoirs to achieve maximum recovery.
The theoretical studies involved development of the differential equations which describe the spontaneous imbibition of water by an oil-saturated rock. The dependence of the rate of water intake by the rock on the permeability, interfacial tension, contact angles, fluid viscosities and fluid saturations is discussed. A few experiments were performed using core samples to determine the effects of core length and presence of a free gas saturation.
The role of water imbibition in recovery of oil from a fractured-matrix reservoir by water flooding was investigated by use of a laboratory model. This model was scaled to represent one element of a fractured-matrix formation. Water floods were made at various rates with several fracture widths. Interpretations were made of the behavior expected in a system containing many matrix blocks.
The presence of a free gas saturation was found to reduce the rate of water imbibition. In the reservoir prototype of the fractured-matrix model, water imbibition rather than direct displacement by water was the dominant mechanism in the recovery of oil at low rates.

Introduction
Imbibition may be defined as the spontaneous taking up of a liquid by a porous solid. The spontaneous process of imbibition occurs when the fluid-filled solid is immersed or brought in contact with another fluid which preferentially wets the solid. In the process of wetting and flowing into the solid, the imbibing fluid displaces the non-wetting resident fluid. Common examples of this phenomenon are dry bricks soaking up water and expelling air, a blotter soaking up ink and expelling air and reservoir rock soaking up water and expelling oil.
The Effect of Crossflow on Waterflooding of Stratified Reservoirs
Authors: El-Khatib Noaman 
Published: December 2007

Abstract
A mathematical model is developed for waterflooding performance in linear stratified systems for both cases of non-communicating layers with no crossflow and communicating layers with complete crossflow. The model accounts for variation of porosity and saturation in addition to permeability of the different layers. The model predicts the fractional oil recovery, the water cut, the total volume injected, and the change in the total pressure drop, or the change in injection rate at the water breakthrough in the successive layers. A systematic procedure for ordering of layers and performing calculations is outlined. A procedure for combining layers to avoid instability in the case of low mobility ratio is introduced.
The developed model is applied to different examples of stratified reservoirs. The effects of mobility ratio and crossflow between layers are discussed. The effects of variable porosity and fluid saturation are discussed also.
It was found that crossflow between layers enhances the oil recovery for systems with favorable mobility ratios (λw/λo &lt; 1) and retards oil recovery for systems with unfavorable mobility ratios. It was found also that crossflow causes the effect of the mobility ratio on oil recovery to become more pronounced. The variation of porosity and fluid saturation with permeability is found to increase oil recovery over that for the case of uniform porosity and saturation for both favorable and unfavorable mobility ratios.
A Small-Volume Continuous Oil/Water Separator for Laboratory Displacement Experiments
Authors: Bretz R.E. , Pelletier M.T. , Orr F.M. 
Published: December 2007

Introduction
An experimental task commonly encountered in laboratory core displacement experiments is the separation of oil and water phases. While such physical separations are not inherently difficult, they can be time-consuming and may lead to material-balance errors if numerous small samples are collected. In this paper, we describe an oil/water separator of low volume that relies on the wetting characteristics of commercially available filter membranes. Because a flowing stream containing oil and water can be separated continuously without a large-volume mixing cell, the separator allows on-line measurement of the compositions of oil and brine streams. It might also prove useful in relative permeability measurements. permeability measurements. Description and Operation
Fig. 1 is a schematic of the device. The two-phase fluid enters the chamber between two porous membranes having different wetting behaviors. Oil, the less-dense phase, rises and contacts the upper, hydrophobic phase, rises and contacts the upper, hydrophobic membrane. Water settles and contacts the lower, water-wet membrane.
Because it is hydrophobic, the upper membrane resists passage of water through its pores but readily admits the passage of water through its pores but readily admits the nonpolar oil. The lower membrane can be wet by either oil or water but, if first wet by water, surface tension effects will prevent oil from entering the pores. Therefore. the first step in operating the separator is to prime it with water to establish a water-wet condition, which must be maintained during operation.
Before the separator is assembled, we saturate the water-wet membrane using a vacuum to eliminate air from the pore spaces. After assembly, we fill the separator with water to the level of the vent of the siphon-breaker.
JPT
P. 487
Field Test Confirms Accuracy of New Bottom-Hole Pressure Gauge
Authors: Lozano G. , Harthorn W.A. 
Published: December 2007

Abstract
Maihak bottom-hole pressure gauges have been field tested in three wells in the San Joaquin Valley, Calif. These are the first known installations of this surface-indicating gauge in the U. S. although it has been used several years in Europe.
The gauge, manufactured by the H. Maihak Co., Hamburg, Germany, consists of a transmitter located at the bottom of the tubing and a receiver at the surface. The signaling circuit consists of a single conductor wire strapped to the outside of the tubing and the tubing itself. Measurements have been made successfully as deep at 6,885 ft. Fig. 1 is a schematic diagram of the system. The gauge appears accurate and reliable and should be a useful addition to the tools of the petroleum engineer.

Introduction
Bottom-hole pressure is one of the most valuable tools of the reservoir engineer. To a lesser degree it is also valued by the production foreman, mechanical engineer and others responsible for efficient production of oil. Existing instruments to measure bottom-hole pressure, although accurate and reliable, have serious limitations. With certain exceptions they are not equipped to telemeter data from the bottom of the well and their utility therefore is limited to occasional measurements. In addition, the high cost of running and retrieving the instruments sometimes discourages their use. This is particularly true in pumping wells where rods or tubing must be pulled to run and retrieve the instruments. A definite need has existed for pressure instruments which will continuously, or on demand, telemeter their data from the well without pulling rods or tubing. The successful development and application of such instruments should open new horizons to reservoir and production engineers and more efficient development and production practices will almost certainly follow. When we learned that the Maihak bottom-hole pressure gauge had been successfully applied in European oil fields, we obtained several for testing. The purpose of this paper is to report on tests made at three wells in the San Joaquin Valley and to make the equipment known to the domestic oil industry.
Accuracy of JBN Estimates of Relative Permeability: Part 1—Error Analysis
Authors: Tao T. M. , Watson A. T. 
Published: December 2007

Abstract
The accuracy of relative permeabilities estimated from displacement experiments by the Johnson, Bossier, and Naumann (JBN) method is considered. A Monte Carlo error analysis is developed to provide quantitative measures of that accuracy. The Monte Carlo error analysis is used to investigate the effect of different experimental operating conditions on the accuracy of relative permeability estimates.
A Numerical Solution of the Linear Displacement Equation with Capillary Pressure
Authors: McEwen C.R. 
Published: December 2007

Introduction
The displacement equations of Buckley and Leverett have been successfully applied to the prediction of oil recovery in frontal drives for a number of years. Commonly, the capillary pressure term is omitted from Leverett's fractional flaw formula. The resulting saturation-vs-distance curves became multi-valued, however. Buckley and Leverett, recognizing that the neglect of capillarity was most likely the cause, proposed that this part of the solution be ignored.
An ingenious method of propagating a discontinuity in place of the multi-valued portion of the curve was devised by Cardwell using "non-capillary displacement theory". However, it would seem that a complete description of the displacement process would require the inclusion of capillary forces.
Three publications on displacement theory have appeared in which capillary pressure was included. Terwilliger, et al, calculated saturation profiles which matched those which they observed when gas displaced water vertically downward. Based on their study, Jones-Parra and Calhoun proposed a method of computing saturation distributions sufficiently removed in time from the initial conditions so that all saturations in the flood front region were assumed to move with the same velocity. This latter assumption corresponds to the tangent construction on the flowing fraction-vs-saturation curve proposed by Welge.
The Displacement of Residual Crude Oil by CO2 and Nitrogen in Gravity Stabilized Systems
Authors: Doscher T. M. , Oyekan R. O. , El Arabi M. 
Published: December 2007

Abstract
Physical model studies of the displacement of residual oil by CO2 have led to the conclusion that the driving mechanism for the process is that of a gas drive of the swollen crude. In this final phase of the study, the fluid/fluid displacement process was gravity-stabilized; mixing of the CO2 with the residual crude oil was minimized. As a result, the performance of CO2 was only marginally better than that of relatively insoluble nitrogen.
Analytical Well Models for Reservoir Simulation
Authors: Abou-Kassem Jamal H. , Aziz Khalid 
Published: December 2007

AbstractThe computation of flowing-well bottomhole pressure from the pressure of the block containing the well or of well flow rate when the flowing bottomhole pressure is specified are important considerations in reservoir simulation. While this problem has been addressed by several authors, some important aspects of the problem are not treated adequately in the literature.We present an analytical method for computing the well-block factors (constants of the PI) for a well located anywhere in a square or rectangular block (aspect ratio between ½ and 2). Equations for well geometric factors and well fraction constants are given for gridblocks of various types, containing a single well, encountered in reservoir simulation studies. The equations given in this paper can be used for both block-centered and point-distributed grids in five- and nine-point two-dimensional (2D), finite-difference formulations. The radial flow assumption used in deriving the equations in this paper is not always strictly valid; however, for most practical situations it provides an adequate approximation for near-well flow.
Gas Phase Appearance and Disappearance in Fully Implicit Black Oil Simulation
Authors: Forsyth P. , Sammon P. H. 
Published: December 2007

AbstractThis paper describes the pseudogas and variable substitution methods for handling gas phase appearance/disappearance in fully implicit black oil simulation. The results of several test runs indicate that there is virtually no difference between these two methods in terms of efficiency. The pseudogas method is easier to program than variable substitution but requires some crucial reallocations of saturations and shows greater material balance errors.
Computer-Assisted Tomography for the Observation of Oil Displacement in Porous Media
Authors: Wang Simon Y. , Ayral Seyda , Gryte Carl C. 
Published: December 2007

Abstract
Computer-assisted tomography (CAT) is used to obtain cross-sectional images of Berea sandstone cores during oil displacement experiments. Local oil saturation averaged over an area of about 0.03 × 0.03 in. [0.8 × 0.8 mm] square is computed as a function of spatial position and time. A series of CAT scan images displaying the time evolution of the fluid distribution at one cross section are shown to illustrate the formation of viscous fingers.
Manual and Automated Turbidimetric Methods for the Determination of Polyacrylamides in the Presence of Sulfonates
Authors: Kuehne D. L. , Shaw D. W. 
Published: December 2007

Abstract
Polymers and sulfonates are often part of the multicomponent chemical systems designed to increase oil recovery from depleted reservoirs. The objective of this work was to develop reliable, analytical methods for measuring Polyacrylamide concentration in the presence of sulfonates. The need for new or improved methods arose because petroleum sulfonates caused interference with the standard turbidimetric method for determining Polyacrylamides. This interference was eliminated by the addition of a butanol-extraction step to remove sulfonates.
Based on the new manual procedure, an automated method was developed for use with a Technicon Auto-Analyzer™ to reduce analysis time. The automated method was designed with four modes of operation to cover high and low polymer concentrations with and without sulfonates present in the samples. Polymer concentrations ranging from 10 to a maximum of 1,200 wt ppm [10 to 1200 mg/kg] can be measured. A unique feature of the automated method is the continuous-flow solvent extraction. Depending on the mode, Auto-Analyzer throughput is 20 or 30 samples per hour. The accuracy of the results is 5% with extraction and 1% without extraction.
The Origin of Reversible Hydroxide Uptake on Reservoir Rock
Authors: Bunge A. L. , Radke C. J. 
Published: December 2007

Abstract
When reservoir solids reversibly consume hydroxide, the impact on alkaline-waterflood performance can be significant. Only recently has this reaction been recognized as a principal factor influencing oil recovery rates and chemical-pulse depletion.
This paper considers the origin of the reversible hydroxide uptake to be ion exchange of sodium for hydrogen ions. Using a simple, mass-action equilibrium model, we describe the alkali exchange isotherm. Because hydronium and hydroxide concentrations in water are never zero, hydroxide uptake must be reported relative to a reference pH and salinity. With the recognition of a reference state and with the mass-action model, we predict qualitatively the effects of pH, salt concentration, and temperature on the measured hydroxide uptake isotherms for the Wilmington, Ranger-zone sand.
Mineral sites that exchange ions of sodium for hydrogen may also exchange calcium for hydrogen or for sodium. Using simple mass-action equilibria again, we demonstrate that reversible hydroxide uptake depends on hardness concentration and that calcium/sodium, exchange is pH dependent.
Semilog Analysis of the Pulse-Decay Technique of Permeability Measurement
Authors: Chen Techien , Stagg P. W. 
Published: December 2007

Abstract
An alternative solution to the system of equations describing the pulse-decay technique of permeability measurement has been obtained. It is a solution in which the sample PV is not neglected. The experimental data are analyzed by using the slope of a semilog plot to evaluate permeability.
Analytical Model for Vertical Interference Tests Across Low-Permeability Zones
Authors: Bremer R. E. , Winston Hubert , Vela Saul 
Published: December 2007

Abstract
A mathematical model is developed that describes fluid flow and pressure behavior in a reservoir consisting of two permeable zones separated by a zone of low permeability, or a "tight zone." This model can be used to design and to interpret buildup, vertical, interference, and pulse tests conducted in a single well or multiple wells across lithological strata. Dimensionless pressure functions and corresponding parametric type curves are derived to interpret vertical interference test data for tight-zone vertical permeability. Application of these type curves is illustrated using field data from two vertical interference tests. Test results obtained with the tight-zone model are shown to compare favorably with results obtained by using (1) computer simulations and (2) Burns' method based on the uniform anisotropy assumption. Computer simulation using a numerical model also shows that high near-wellbore conductivity from a packer leak or poor cement job could not have adversely affected test results. The model presented and the type-curve interpretation method outlined are accurate for designing and interpreting single-well vertical interference tests across low-permeability zones.
Pressure Transients and Crossflow Caused by Diffusivities in Multilayer Reservoirs
Authors: Gao Cheng-Tai , Deans H. A. 
Published: December 2007

Summary
This paper considers single-phase unsteady flow in a system of homogeneous layers separated by thin, low-permeability shales, and having interlayer crossflow caused by different diffusivities for different layers. The model considers all layers open to a single well that flows at a constant total rate. Numerical simulations of the problem for the semipermeable-wall model are used to find the structure of the crossflows in typical cases. Analytic solutions for pressure and the n − 1 diffusivity crossflows are developed and compared with the numerical results. These solutions show how the diffusivity crossflows depend on layer properties and ordering. Their behavior and properties are discussed and their effects on pressure distributions are shown.