bluuebunny/crossref_metadata_2025_split huggingface dataset:
Block Iterative Methods for Fully Implicit Reservoir Simulation
Authors: Behie A. , Vinsome P. K. W. 
Published: December 2007

Abstract
This paper describes the development of iterative methods suitable for the block-structured Jacobian matrices that occur in multiphase reservoir simulation. Most iterative methods consist of an approximate factorization followed by an acceleration procedure. The acceleration procedure used here is ORTHOMIN.1 Four factorization methods have been investigated that, when coupled with ORTHOMIN, provide four possible iterative algorithms. The first three factorization methods differ only in the number of bands included in the approximate decomposition. The fourth factorization is the most involved and the most powerful of the four methods. It is intended to be used on the equations that occur in thermal simulation, which previously have been considered difficult to solve iteratively. Several examples illustrating the use of the iterative algorithms are described. The algorithms described here are compared with several others on the basis of theoretical work and storage.
Alternatives to the Power-Law Fluid Model for Crosslinked Fluids
Authors: Cloud J. E. , Clark P. E. 
Published: December 2007

AbstractMeasuring the rheological properties of crosslinked fracturing fluids is difficult but important. Fluid properties play a key role in the determination of the final geometry of die created fracture and in the distribution of proppant within the fracture; therefore, an accurate knowledge of these parameters is necessary for optimum treatment design. The first paper1 in this series described a method to measure accurately and reproducibly the rheological properties of crosslinked fracturing fluids. The technique is the first that applies long-accepted mathematical methods to correct the measurements for the deviations in shear rate caused by the non-Newtonian nature of the fluids. This, in turn, allows the rigorous examination of mathematical fluid models to determine which, if any, best describes the flow properties of the fluids.
A Retrospective Look at a Profitable Water Flood
Authors: DeVore S.F. , Wright F.F. 
Published: December 2007

Abstract
The history of Flood 12, a former intensive air-gas repressuring project, is discussed. The sand body is described and core graphs are given showing an upper and lower section of the Bartlesville sand body. The conventional five-spot waterflood development and well completions in these sand sections are outlined. The plant design and distributing systems are reviewed. A comparison is made between intermittent and continuous flowing for producing wells with continuous flowing yielding the better results. The waterflood recovery is determined to be above average for similar nearby projects. Since there seems to be still significant quantities of recoverable oil remaining, especially in the upper sand, plans are proceeding to exploit this reserve.

Introduction
The two leases which make up the area known as Flood 12 are the Riverland and the Scudder, located in the Alluwe pool of Nowata County, Okla. (Fig. 1). Their earlier history has been discussed before. The Riverland is the northernmost 80-acre tract and was formed by unitizing three leases. The Scudder lease, on the south, is also an 80-acre lease. Although the entire 160 acres has been flooded from a single water plant, the oil production of the two tracts has been run from separate tank batteries. Since there has been some difference in the primary history of the two tracts, and also some difference in their development for water flooding, they will be discussed separately.
Both of these tracts were purchased from an independent operator in 1951 as a small part of a larger purchase. Sinclair obtained control of operations Aug. 1, 1951. At that time, the development of the flood was largely completed, the plant was constructed and over 3 million bbl of water had been injected. Except for the change in operating practices instituted by Sinclair and the drilling of additional wells to exploit the sand body more intensively, Flood 12 has been operated from the development program instituted by the former owner. Because it was a part of a large purchase, no actual cash value was assigned to Flood 12 as such. However, the estimated worth attributed to Flood 12 at date of purchase has been more than justified by its performance since then.
Foreign Private Investment- A Boon to Developing Countries
Authors: Just Evan 
Published: December 2007

The high standards of living and improved national security which industrialization can bring are so broadly evident that one cannot name a country which does not cherish the hope of industrializing itself. Why, then, with such a universal aim, do many countries which lack either the capital or the skill to develop their own industries, accomplish so little toward attracting the only functionary who can provide the necessary capital and skill, namely, the foreign private investor? Obviously, because they fail to understand what constitutes a favorable climate for investment, because they have false notions about being exploited or dominated by the foreign investor, or because they are so nationalistic that they refuse to permit outside assistance.
The purpose of this paper is to aid the citizens and policy makers of the developing countries in achieving their aims, by defining the conditions which encourage investment and portraying the results of a policy of encouragement. The following is quoted from Eugene R. Black, president of the World Bank:
"The danger today is not that the foreign investor will ask too much of a developing country, but that the developing countries will do too little to attract him. Today the foreign investor cannot go into a country unless he is actually wanted by the people of the country. By indulging the myth that the private investor is trying to force an entry to engage in some sort of evil exploitation, the less developed countries are cutting themselves off from one of the most productive sources of development assistance available to them. The capital and skills which the private investor brings with him may not be available from anyone else. Particularly, he brings with him the skills of industrial management - skills which have to be seen in action to be learned. If a country is bent on industrializing and having the benefits spread broadly among the people, it can do itself no better service than to seek out the private investor abroad who is willing to risk his capital on the chance of a fair return on a successful venture."
An Accurate Slot-Flow Model for Non-Newtonian Fluid Flow Through Eccentric Annuli
Authors: Iyoho Aniekan W. , Azar Jamal J. 
Published: December 2007

AbstractThis paper describes a new model for obtaining analytical solutions to the problem of non-Newtonian fluid flow through eccentric annuli. A discussion on non-Newtonian rheology is presented, followed by the development and solution of applicable differential equations using the Ostwald de Waele power-law model and a nonrectangular slot.Results indicate that velocity values are reduced greatly in the reduced region of the eccentric annulus. This is important in directional drilling where the drillpipe tends to lie against the hole. Design of mud flow for cuttings transport on the basis of the nominal average velocity could lead to serious problems associated with cuttings buildup in the low-velocity region of the annulus. Other practical ap-plications of this work include the determination of velocity distribution in chemical processes involving fluid flow through eccentric annuli – e.g., heat exchangers and extruders – and more accurate velocity profiles inside journal bearings, particularly for small diameter ratios.The main advantage in the new approach is that iterative finite difference methods used by previous investigators are avoided. Previous work along present lines used a linearized model and resulted in velocity profiles of unacceptable accuracy. This study improves both the accuracy and the solution technique.
Evaluation of the One-Well Uranium Leaching Test: Restoration
Authors: Kabir Muhammad I. , Lake Larry W. , Schechter Robert S. 
Published: December 2007

Abstract
A one-well test to evaluate reservoir properties that govern the restorability of a zone in an underground aquifer to be solution mined for uranium has been considered. The test involves injection of a relatively small volume of leach solution and subsequent production of a larger volume of fluid. Two important parameters— cation exchange capacity and an equilibrium constant—are determined by history matching the effluent composition.
Two different solution techniques are used. By neglecting dispersion and reservoir heterogeneities, an analytical solution based on the method of coherence provides considerable insight into the pertinent features of the production composition history. To include complexities such as dispersion and layering, a two-dimensional finite difference computer simulation is used.
A number of different approaches have been evaluated. The most reliable approach is to use laboratory tests to determine one parameter with core samples and to use production history to determine the other parameter. Measurements of both anion and cation effluent concentrations are required to implement this procedure.
G-2 and G-3 Reservoirs, Delta South Field, Nigeria: Part 1-An Engineering Study
Authors: Poston S. 
Published: December 2007

Summary
This paper describes a two-dimensional, three-phase, black-oil simulation of the G-2 and G-3 reservoirs in the Delta South field offshore Nigeria. The purpose of these studies was to investigate, from an engineering standpoint, various operating schemes for optimizing the oil recovery from each of these highly gravity-segregated reservoirs.

Introduction
The G-2 and G-3 sands are two major reservoirs in the Delta South field. The field is offshore Nigeria in approximately 10 to 16 ft of water (Fig. 1). Production from these reservoirs began in March 1968. By the end of March 1978, about 61.3 MMSTB of oil and more than 64 Bscf of gas were produced from the G-2 reservoir, and about 92 MMSTB of oil and more than 75 Bscf of gas were produced from the G-3 reservoir. These productions represent about 2 1% of the original oil in place (OOIP) for G-2 and 29% of OOIP for G-3. During this period, the average reservoir pressures for G-2 and G-3 declined from 3,936 to 2,665 psig and 3,829 to 2,343 psig, respectively.
The G-2 reservoir is at an average depth of 8,920 ft subsea. It is underlain by the G-3 reservoir, but the two are separated by a shale barrier. The two reservoirs are similar in structure and in rock and fluid properties.
The drive mechanism for these reservoirs is primarily gravity segregation. These reservoirs are characterized as massive, clean sands with high porosity (about 28% for G-2 and 26.5% for G-3) and high horizontal and vertical permeabilities (kh=2,000 md and kv=1,000 md).
This paper presents the results of the current G-2 and G-3 reservoir studies, which are extensions of previous work. First, a history match of 10 years of production performance was made. Later, several prediction cases were run under a variety of operating conditions. This study was undertaken to update the previous match, including the past performance data through March 1978. We believe that, by including more history match data, we have obtained a better reservoir characterization. Although about 20 prediction cases were run for each study, only four pertinent cases for G-2 and five for G-3 are included.
Gulf's two-dimensional, black-oil model in an areal mode has been used for this study. The use of this areal model is believed sufficient in describing the reservoir and fluid flow behavior and is justified since the fluids will be segregated because of the high kv/kh ratio (about 0.5:1 were kh=2,000 md). In this cases, gravity/capillary equilibrium exists throughout the thickness. However, there are some limitations in using an areal model for this study:the well coning effects are represented by well pseudo relative permeability curves and not with grid blocks in the vertical direction,the well completions are represented by modifying the well relative permeability curves, andany well coning effect matched using pseudo relative permeability curves may not be strictly valid for future predictions.
These limitations, however, do not seem to be very important for the G-2 and G-3 reservoirs.
Time-Derived Sigma for Pulsed Neutron Capture Logging
Authors: Randall Russel R. , Fertl Walter F. , Hopkinson Eric C. 
Published: December 2007

Summary
This paper reviews field applications of the Dresser Atlas Neutron Lifetime Log™ (NLL) service and examines recent technical advances in the instrumentation and data-analysis system. The major improvement discussed is a new method for computing S, the thermal neutron capture cross section of an earth formation. In the new method, the time after the neutron burst is measured for each gamma ray pulse detected by the instrumentation system within a gate of fixed width. This "average pulse time" is uniquely related to the thermal neutron decay rate observed in a borehole environment.
The technique discussed is applicable for any condition where the neutron or gamma ray flux is time-dependent. The advantages of this signal-processing method, however, are most apparent for cases of rapid flux change with time, as in an exponential decay. A simple two-gate method of measurement suffers, statistically, from the lower count rate of the second gate. An average-pulse-time measurement over the same range covered by both gates of a two-gate system is less affected by statistical deviations than the ratio normally formed between the two gates.
Some important advantages result from this type of signal processing when applied to the NLL service. First, the statistical accuracy of the log is improved; second, the instrumentation required for implementation of the method is not complicated. Also, the average-pulse-time measurement can be made with either digital or analog equipment, and since it involves only simple arithmetic computations, the method is much simpler to implement than either least-squares or correlation methods.

Introduction
The NLL service1 was introduced in the early 1960's; it was the first measurement through casing that could distinguish and quantitatively evaluate oil and gas in saline formation water environments. More recently, the Dual Detector Neutron Lifetime Log (DNLL) service2 has been used (1) to explore for hydrocarbon resources behind pipe, (2) to monitor the production behavior of wells, (3) to plan workovers properly, (4) to determine residual oil saturation for enhanced-recovery projects, etc.
Although the carbon/oxygen3 (C/O) log provides a reliable cased-hole formation evaluation in fresh and brackish formation water environments, the DNLL service is applicable when logging through casing and/or tubing in saline environments. As discussed in detail in the literature, the basic measurement is the thermal neutron absorption (capture) cross section, S, of a subsurface formation.
Advanced methods of processing the data recorded by such a pulsed neutron capture logging system are presently under development. These improvements include (1) the average-time technique4 and (2) the sigma-dependent positioning of a single gate exhibiting a fixed gate width of 600 µseconds.
The basic theoretical considerations of these improvements are discussed, and supporting field data are presented.
A Simple Technique To Determine the Unknown Constant in y or x for Producing y vs. x as a Straight Line in Reservoir Engineering Problems
Authors: Cheng M.C. Aaron 
Published: December 2007

Introduction
It is common practice in some reservoir engineering and well-testing problems to plot a certain function A vs. another function B such that a straight line results. One well-known example is the graphical interpretation of the material-balance equation as a straight line. However, most of the time there is an unknown factor in either A or B. A trial-and-error procedure for estimating this factor until a straight line results is the method usually mentioned in the literature. This paper presents a simple technique for computing, the unknown factor directly.

Technique
Using common algebraic notations, a straight line has the equation y = mx + b.
A plot of y vs. x will give a straight line with slope m and intercept b. Also, if three (or more) pairs of data, (x1, y1),(x2, y2), and (x3, y3), are known,
y2 - y1 y3 - y1 --------- - --------- = m x2 - x1 x3 - x1
or y2 - y1 y3 - y1 --------- - --------- = 0. x2 - x1 x3 - x1
If y is comprised of a certain unknown constant, say c, this equation can be expressed as
f(c) = ----------------- - ---------------- = 0.......(1) x2 - x1 x3 - x1
Similar expression holds for x being a function of c.
Eq. 1 is the formulation of the common root-solving problem, where c is the root to be determined such that problem, where c is the root to be determined such that f(c)=0. Depending on the nature of the equation, the solution of f(c)=0 can be obtained with a closed type formula or, if this is not possible. with an efficient iterative root-solving algorithm such as the Newton's method.

Selection of Data Points
The current technique requires the use of three data points for formulating Eq. 1. If more than three points points for formulating Eq. 1. If more than three points are available, the selection of any three points from the given data would be adequate if all the data points are known to be correct. This is valid because any three correct data points would yield the same root c in Eq. 1. However, if it is not known which data points are correct, which three points to choose is a problem. One logical approach is to choose the two endpoints, (x1, y1) and (xn, yn) and the median or central point from the given set of n data points (x1, y1),(x2, y2),....., (xn, yn) to span the whole data set.
The following examples illustrate the current technique.
Example 1-Determination of Pressure Buildup Correction Factor C
The after flow analysis of Russell for pressure buildup analysis requires the plot of p/(1–1/C t) vs. log t to be a straight line. The correction factor C is usually an unknown. Russell suggested that C be determined by trial and error until the plot is a straight line. The current technique instead solves for C directly. Dake's after flow analysis data are used in this example and there are 15 data points available. Select the two endpoints and the central point (Table 1).
JPT
P. 1140
Generation of Ultralow Tensions Over a Wide EACN Range Using Pennsylvania State U. Surfactants
Authors: Klaus E. E. , Jones J. H. , Nagarajan R. , Ertekin T. , Chung Y. M. , Arf G. , Yarzumbeck A. J. , Dudenas P. 
Published: December 2007

Abstract
Saturated paraffinic and naphthenic hydrocarbons without aromatics have been vapor-phase oxidized to produce cyclic ethers and lesser amounts of olefins. These cyclic ethers appear to be effective cosurfactants for the preparation of slugs containing petroleum sulfonate surfactants. The cyclic-ether/olefin mixture has been reacted with SO3 from oleum or liquid SO3 to form sulfonates comprising a mixture of mono-, di-, and polysulfonates. The reaction products consisting of the sulfonates, unreacted oxidized products, and residual hydrocarbons have been extracted with isopropanol (IPA) to give two sulfonate fractions. The first fraction is predominantly monosulfonate with lesser quantities of disulfonates. The second fraction consists primarily of di-, tri-, and polysulfonates.
The monosulfonate fraction in a low-concentration slug exhibits ultralow interfacial tension (IFT) against hydrocarbons of low equivalent alkane carbon number (EACN). The behavior of this fraction is similar to that of the commercial sulfonates in that its ability to generate low IFT is confined to a narrow range of EACN. To achieve low IFT's at higher EACN in the range of a Pennsylvania crude oil, it is necessary to raise the equivalent weight of the Pennsylvania State U. monosulfonate fraction by blending with a commercial sulfonate of higher equivalent weight.
Recent studies show that by mixing the two IPA fractions of the sulfonation products, a remarkably new surfactant behavior is obtained. In contrast to the behavior of other surfactants that yield ultralow tensions over only a narrow range of values of EACN, this mixture of mono- and polysulfonates generates low IFT's over a wide range of EACN extending from C5 to C12. The salt tolerance of monosulfonates and polysulfonates, either alone or in mixtures, is rather high, and even at about 4 wt% NaCl, the surfactant solutions remain stable and yield low IFT's against crude oil.
Carbon Dioxide Displacement of a West Texas Reservoir Oil
Authors: Yellig William F. 
Published: December 2007

AbstractThis paper presents results of an extensive study to understand CO2 displacement of Levelland (TX) reservoir oil. The work was conducted to support Levelland CO2 pilots currently in progress. Experimental displacement tests were conducted at various pressures, core lengths, and CO2 frontal advance rates. The experimental system included a novel analytical technique to obtain effluent compositional profiles within the oil-moving zone at test conditions.The results of this study show that at pressures greater than the CO2 minimum miscibility pressure (MMP), a multicontact miscible displacement mechanism predominates. Miscibility is developed in situ by vaporization-or extraction-type mass transfer. The laboratory lengths required for CO2 to develop miscibility and exhibit miscible displacement efficiency were found dependent on the phase equilibria of the CO2/Levelland oil system. Displacements requiring the greatest length to develop miscibility were at pressures where single-contact mixtures of CO2 and Levelland oil form two liquid phases.A companion paper10 demonstrates the use of the analytical technique developed in this study to obtain process data from a CO2 field pilot test. In addition, the mechanistic information obtained from this study is used to interpret the process data from the pilot test. The results have application to other reservoir oils whose phase equilibria with CO2 are similar to the CO2/ Levelland oil system.