bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Evaluation of Gas Injection in the Emery West Pool, West Coyote Field, California
Authors: Craddock Sheldon F. 
Published: December 2007

Abstract
The Emery West pool provides an 11-year case history of successful gas injection operations in a depletion type California reservoir producing 32° API oil. The original oil in place was 50 million bbl. Reservoir calculations indicate that only 23 per cent of this oil would have been recovered by normal depletion, but that 33 per cent will be recovered by gas injection operations. This is an increase if 5 million bbl of oil recovery by gas injection. In addition 3,250,000 bbl of natural gasoline and LPG, not recoverable by normal depletion, will be recovered as a result of gas injection. This is an increase of over 200 per cent in the expected natural gasoline and LPG recovery.

Introduction and History
After 11 years sufficient historical data is available on the Emery West pool to predict with some confidence the ultimate benefit from gas injection. The early history of the pool and the details of the injection operations have been adequately presented in a previous paper and are, therefore, only briefly summarized herein. The purpose of this paper is to review the performance of the pool to date, to present the results of reservoir calculations predicting the future production, and to summarize the benefits of gas injection.
The Emery West pool was discovered in 1930. Development proceeded gradually and the basic well spacing pattern was essentially completed in 1943. There has been no drilling activity subsequent to 1943 except in the year 1952. In that year seven small producers were completed at the west end of the pool.
Gas injection was started in July, 1944. Ten MMcf/D of gas was injected into the pool from 1944 to 1949 when injection was increased to 20 MMcf/D to provide virtually full pressure maintenance. Injection has continued at 20 MMcf/D since 1949.
A Strongly Coupled, Fully Implicit, Three-Dimensional, Three-Phase Well Coning Model
Authors: Trimble Russell H. , McDonald A. E. 
Published: December 2007

Abstract
WELCOS is a robust, three-dimensional, three-phase well coning simulator that couples the well rate equation to the reservoir flow equations. This strong coupling allows well rate to be determined simultaneously with reservoir pressures and saturations. The flexibility obtained permits the use of dynamic constraints on well rates, resulting in a highly stable model. The model may be used to obtain the maximum well productivity for a given set of physical limitations and regulatory constraints – e.g., minimum surface pressure, maximum allowed GOR, WOR, water rate, gas rate, etc. The model can function either as a production well or an injection well and, in general, may be used to study any single-well behavior.
This paper describes a strongly coupled formulation and discusses its utility in relation to other implicit models. The linearization of the nonlinear finite difference equations and solution of the resulting linear equations are discussed. Example field applications are included to show the utility of user-supplied production constraints in determining well performance.
Determination of Relative Permeability and Recovery for North Sea Gas-Condensate Reservoirs
Authors: Chen H. L. , Wilson S. D. , Monger-McClure T. G. 
Published: December 2007

Summary
Coreflood experiments on gas condensate flow behavior were conducted for two North Sea gas condensate reservoirs. The objectives were to investigate the effects of rock and fluid characteristics on critical condensate saturation (CCS), gas and condensate relative permeabilities, hydrocarbon recovery and trapping by water injection, and incremental recovery by subsequent blowdown.
Both CCS and relative permeability were sensitive to flow rate and interfacial tension. The results on gas relative permeability rate sensitivity suggest that gas productivity curtailed by condensate dropout can be somewhat restored by increasing production rate. High interfacial tension ultimately caused condensate relative permeability to decrease with increasing condensate saturation. Condensate immobile under gas injection could be recovered by water injection, but more immediate and efficient condensate recovery was observed when the condensate saturation prior to water injection exceeded the CCS. Subsequent blowdown recovered additional gas, but incremental condensate recovery was insignificant.
When Do Drilling Alliances Add Value? The Alliance-Value Model
Authors: Brett J. F. , Craig V. B. , Brett K. V. , Wadsworth D. B. , Pile K. E. 
Published: December 2007

Summary
A recent Gas Research Institute report details three previously unstudied aspects of alliances: specific measurable factors that improve alliance success, how a successful alliance should be structured, and when an alliance makes economic sense. For the purposes of this report, an alliance is defined by "technical process integration," which includes joint planning, execution and evaluation. Technical process integration shifts the definition of an alliance beyond a simple focus on the commercial terms. The most innovative tool to emerge from the report, the Alliance-Value model, addresses those aspects surrounding when an alliance makes economic sense.
The theory behind the Alliance-Value model is that the long-term viability of any drilling relationship hinges on its ability to create real value and achieve stability. Based upon the report's findings, the most effective way to form such an alliance is through a detailed description and integration of the technical processes involved. This new type of process-driven alliance is characterized by a value chain which links together a common set of technical processes, mutually defined bottom-line goals, and shared benefits.
Building a process-driven alliance requires time and people and therefore has an associated cost. The real value generated by an alliance must exceed this startup cost. The Alliance-Value model computes the net present value of the cash flows for four different operating arrangements: (1) business as usual (conventional competitive bidding process), (2) process-driven alliance (linking technical processes to accelerate production and reduce expenses), (3) incentivized process-driven alliance (linked technical processes with performance incentives to promote stability), and (4) no drill case (primarily used to gauge the market value of services).
These arrangements test different degrees of process integration between an operator and its suppliers. They can also help determine if the alliance can add enough value to exceed startup costs and if the relationship will be stable. Each partner can test the impact of the relational structure on its own profitability. When an alliance is warranted, all participants can benefit from real value generated in a stable relationship. However, relationships that focus on commercial terms, instead of on process linking, may be playing a zero-sum, no-win game.
The Effect of Bacteria on Sandstone Permeability
Authors: Kalish P.J. , Stewart J.A. , Rogers W.F. , Bennett E.O. 
Published: December 2007

Abstract
Detailed descriptions are given of materials, apparatus and the experimental procedure used to study the effect of bacteria on sandstone permeability. The factors affecting permeability during injection of bacterial suspensions which have been investigated are:
- concentration of bacteria;
- core permeability and median pore size;
- species of bacteria, mode of aggregation and relative size;
- injection rate or pressure differential;
- mean pressure; and
- depth of penetration of bacteria.
The investigation demonstrated that bacteria cannot reduce core permeability to zero and that their effect on permeability is subject to definite limitations. Remedial or permeability restoration studies also were made. Acidization in combination with reverse flow was found to be an effective method for restoring permeability in cores partially plugged with bacteria.
The relationship between the bacterial quantities in the laboratory tests and those found in field operations is discussed. The linear laboratory flow data have been translated into terms of field radial systems; these data indicate the most practical methods of maintaining injection rates in the presence of bacteria are to increase injection pressures or hydraulically fracture the formation.

Introduction
It has long been known that various bacteria flourish in the above-ground components of oil field water- injection systems. The presence of these bacteria has led to the suspicion that they might enter into the causes for reduction of injection well permeability, but only recently has an attempt been made to describe the effects quantitatively. Biocides are used in many cases without a firm knowledge as to whether the bacteria are killed, or if they are, whether the dead cells affect formation permeability. This project was undertaken as part of a study to determine the effect of bacteria, residual oil and precipitated solids such as iron sulfide or calcium carbonate on the permeability of sandstones and to learn whether any of these materials adversely affect brine injectivity in secondary recovery or disposal operations. This report deals with that portion relating to the effect of bacteria.
An Oil Man Looks at Atomic Energy
Authors: Duce James Terry , Chapman A.H. 
Published: December 2007

Introduction
In Oct., 1954, the authors prepared a study of future energy requirements of the world. These requirements were balanced against reserves of conventional fuels. To fill the gap left by future deficiencies of oil and coal, it was shown that atomic energy could play a vital role.
We have now had the opportunity to examine the papers presented at the United Nations Conference on the Peaceful Uses of Atomic Energy. We now can present a better assessment of when and how atomic energy is likely to be used to help satisfy the world's seemingly insatiable thirst for power. In this paper we will point out some interesting highlights in nuclear development, some problems to be overcome in commercial utilization, and estimates of the future relationships between conventional and nuclear power.

Military Leadership
In the past, the first change in energy relationships has almost invariably appeared in military operations, and in that respect today is no different from the past. With the advent of atomic energy, the traditional pattern is repeating itself. Military impetus has sparked preliminary development and economic necessity for the development of new sources of energy. This is clearly visible to students of the energy producing industries. Scientists assure us that the world's crust will yield almost limitless reserves of atomic fuels and that they are well on the way to devising dependable means for commercial utilization of atomic energy.
In discussing atomic energy, oil men must not view the future with the trepidation of the buggy whip manufacturer who saw the automobile as the ruination of his business. At a time when the demand for energy in the world is following such a sharply ascending curve - with ample room for all known forms - we should welcome the contribution of the atom to the over-all energy supply and thus to the prosperity of the world.
We shall proceed, therefore, to discuss some recent developments in atomic technique and economics and also try to take a look into the future.
Waterflooding Performance of Communicating Stratified Reservoirs With Log-Normal Permeability Distribution
Authors: El-Khatib Noaman 
Published: December 2007

Summary
An analytical solution is developed for waterflooding performance of layered reservoirs with a log-normal permeability distribution with complete crossflow between layers. The permeability distribution is characterized by the Dykstra-Parsons (DP) variation coefficient VDP or the standard deviation of the distribution σk. The performance is expressed in terms of vertical coverage as function of the producing water-oil ratio. Also an expression for the dimensionless time (pore volumes of injected water) at a given water-oil ratio is derived. Expressions are also derived for pseudorelative permeability functions and fractional flow curves that can be used in reservoir simulation. Correlation charts are also presented to enable graphical determination of the performance. The variables are combined in such a way that a single chart is constructed for the entire range of water-oil ratio, mobility ratio and permeability variation.
Analogy to the Buckley-Leverett (BL) multiple-valued saturation profile is found to occur at low mobility ratios (M&lt;1) where a multiple-valued displacement front is formed. A procedure similar to the BL discontinuity is suggested to handle this situation. Successive layers with different permeabilities are allowed to move with the same velocity resulting in a single-valued profile with a discontinuity. No such behavior is observed for mobility ratios greater than unity. A criterion for the minimum mobility ratio at which this behavior occurs is presented as a function of the variation coefficient VDP.
Determination of Waterflood Residual Oil Saturation From Routine Core Analysis
Authors: Kazerni H. 
Published: December 2007

Proposal Proposal Rathmell et al. proposed a method for estimating water-flood residual oil saturations from core saturations where the cores must he taken with water-base muds having a filtrate loss in excess of 5 cc at bottom-hole conditions. Their equation is
(So)res = (So)coreBoE .........................(1)
where
(So)res = average post-waterflood residual oil saturation in the flooded region of the reservoir
(So)core = average oil saturation from cores
BO = oil formation volume factor at the time of coring
E=bleeding factor- proposed to he 1.11.
In my opinion. Eq. 1 must be corrected for waterflood displacement efficiency through multiplication by the reciprocal of the conformance factor. The conformance factor may be obtained from a reservoir simulator that accounts for reservoir heterogeneity, capillary effects, and mobilities of oil and water. in the absence of a reliable reservoir simulator, the conformance factor is estimated by (1 − V2)/M, as reported by Craig. Using this empirical factor, I propose Eq. 2 as the most practical and the most convenient method to calculate waterflood residual oil saturation from the average of the oil saturations obtained from routine core analysis (provided the cores are taken with water-base mud):
(So)res = (So)core BoE M .........(2) 1 − V2
where
M= mobility ratio, the ratio of the mobility of water at the average water saturation in the reservoir at breakthrough to the mobility of oil in the oil bank ahead of the displacing front. V= permeability variation calculated from reservoir core samples as described in Ref. 2.
Example
This example applies to the 119-R Project of the Henry reservoir, which has been reported elsewhere. The data are obtained from Marathon Oil Co. files or from Ref. 3. The average core oil saturation was obtained from cores taken at the end of waterflooding and before the application of the Maraflood process. The pertinent data are
(So)core = 0.248 SWc = 0.25 M = 1.3 V = 0.325
Using Eq. 2 we get
(So)res = (0.248)(1.01)(1.11) 1.3 (So)res 1 − (0.325)−2
The post-waterflood residual oil of 0.404 compares favorably with the results of other methods reported in Ref. 3. In fact, the "best" estimate of post-waterflood residual oil for the 119-R Project, as reported in Refs. 4 and 5, is 0.40.
Mud Filtration at the Bottom of the Borehole
Authors: Havenaar I. 
Published: December 2007

This Technical Note is one page in length.

Experimental Data
In an article by C. K. Ferguson and J. A. Klotz, experiments on the filtration of drilling muds under borehole conditions are discussed. Experimental data on mud filtration through the wall and the bottom of the hole are presented. From the data on bottom-hole filtration it was concluded that the filtrate does not flow freely into the formation, but that the pores of the formation are plugged by the mud.
A quantitative interpretation of the data can be given, by using a formula for bottom-hole filtration, derived below. This formula is based on the following assumptions,Each time a blade of a drag bit, or a cone of a roller bit, moves along the bottom of the hole, the mud cake is completely removed.A new mud cake is immediately formed on the freshly produced surface, and losses of "whole" mud into the formation are negligible (this is equivalent to an immediate plugging of the pores).The filtration of the mud on the bottom of the hole follows the classic law: (Equation 1), where t is the time required to yield a volume of filtrate V, A is the surface area of filter cake, and C is a constant. The application of this equation means that any eroding effect of the mud stream on the mud cake is neglected.
Estimated Effect of Horizontal Fractures in Thick Reservoirs on Pattern Conductivity
Authors: Landrum Bobby L. , Crawford Paul B. 
Published: December 2007

Abstract
An electrical model study has been made to estimate the effect of horizontal fractures in thick reservoirs on pattern conductivity. For the patterns studied, it is shown that fracturing all the wells in the pattern increases the conductivity considerably more than fracturing only single wells. For certain conditions one large fracture is more effective in increasing conductivity than several fractures of half the radius. Particularly in thick reservoirs and with large fractures, the center of the pay is found to be more responsive than other locations. For the seven-spot pattern fracturing the center well is more effective in increasing pattern conductivity than fracturing all outer wells with fractures of the same size.

Introduction
Although commercial fracturing has been used for some time very little quantitative information is known about the effects of fractures on reservoir behavior. The purpose of this work was to estimate the effect of horizontal fractures in thick reservoirs on the conductivity of various flooding and cycling patterns. Circular fractures originating at the wellbore and extending symmetrically into the pay were considered.

Analysis
Electrical models were used in making this study. Horizontal fractures were simulated by copper sheets shaped like the fractures and of a proportional size; the well bore was simulated by a copper wire. A dilute salt solution served as a conducting medium. A conductivity bridge was used to measure the conductivities of the various patterns studied.

Effect of Horizontal Fractures on Conductivity
Fig. 1 shows the effect on square and staggered line-drive patterns of horizontal fractures located in the center of the pay. The model is shown schematically in the insert. The upper and lower groups of lines show the effect on conductivity when all wells are fractured, and when only one well is fractured, respectively. In general, pattern conductivities are substantially improved by fracturing all wells.
Fig. 2 shows the effect of multiple horizontal fractures on the conductivity of a line-drive pattern.
Comparative Evaluation of Foam Stability to Oil
Authors: Mannhardt Karin , Novosad J. J. , Schramm L. L. 
Published: December 2007

Summary
Foam performance was evaluated by several experimental methods (corefloods, bulk foam stability, micromodel observations, interfacial parameters) using three commercial surfactants, either by themselves or mixed with a fluorinated surfactant. The presence of oil reduced foam mobility reduction factors (Fmr) to different degrees; excellent Fmr were still attained with some surfactants in the presence of residual oil. Using the fluorinated surfactant as additive enhanced the oil tolerance of some, but not all, foams. The tested foams exhibited oil transporting properties. Each foam adjusted to its own residual oil saturation and corresponding level of mobility reduction. Foam performance in corefloods did not correlate in general with predictions based on the other experimental methods.
Surfactant Criteria for Successful Carbon Dioxide Foam in Sandstone Reservoirs
Authors: Kuhlman M. I. , Lau H. C. , Falls A. H. 
Published: December 2007

SummaryLaboratory results demonstrate that surfactant adsorption on sandstones is minimized and foam performance improved by reducing the ethoxylate chain length in alcohol ethoxy sulfonates and blending unethoxylated and ethoxylated sulfonates to optimize desirable properties. The results also show that laboratory adsorption measurements can only be extrapolated to reservoirs by (1) replicating the anaerobic conditions of reservoirs, and (2) differentiating authogenic minerals from drilling mud found in reservoir cores.
Control-Volume Method for Simulation in the Well Vicinity for Arbitrary Well Configurations
Authors: Ding Yu , Lemonnier P. A. , Estebenet Thierry , Magras J-F. 
Published: December 2007

Summary
Advanced wells are getting more and more used in reservoir engineering to increase the oil recovery. However, accurate modeling of these kinds of wells is still a challenge due to the scaling problem related to the large gridblocks used in the simulation and the small wellbore diameter. In this paper, a control volume method is proposed, which is suitable for the well singularity flow modeling. Both the well performance and the flux calculation in the well vicinity can be accurately handled with this method. The use of this control volume approach for advanced well modeling with distorted gridblocks is particularly addressed. Some examples are presented to illustrate the efficiency of the approach.