bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Treatment of Dispersion in Numerical Calculation of Multidimensional Miscible Displacement
Authors: Peaceman D.W. 
Published: December 2007

Abstract
In previous papers by this author on numerical calculations of multidimensional miscible displacement, some simplifying assumptions were made in writing the dispersion term of the differential equation. It was assumed that the flow vector were essentially parallel to the x-axis. However, in most multidimensional miscible displacements, the flow vectors are not so simply oriented with respect to the coordinate axes. This paper derives the correct dispersion term for the more general case; gives a difference approximation for the dispersion term; and derives the stability criterion for the corresponding explicit difference equation.
Introduction
The differential equation for solvent concentration in miscible displacement is:
.........(1)
where v is the bulk flow velocity, C is concentration and D is the dispersion coefficient. For simple isotropic dispersion, D is a scalar quantity. however, dispersion in porous media is not generally isotropic since it is usually greater in the direction parallel to flow than in the direction transverse to flow. Hence, D must be treated as a tensor. Scheidegger has shown for an isotropic porous medium that, for the dispersion tensor to be invariant under coordinate transformations, there can be no more than two independent dispersivity factors; these are the longitudinal dispersivity D1, which acts in the direction of flow, and the transverse dispersivity Dt, which acts in the direction perpendicular to flow, In general, both D1 and Dt are functions of the magnitude of the flow velocity. In previous papers, the author made some simplifying assumptions in writing the dispersion term of the differential equation. It was assumed that the flow vectors were essentially parallel to the x-axis and, therefore, that the dispersion term. D C could be replaced by the sum:
...... (2)
However, in most multidimensional miscible displacements, the flow vectors are not so simply oriented with respect to the coordinate axes. The purpose of this paper is to derive, without using tensor notation, the correct dispersion term for the more general case, to give a difference approximation for the dispersion term, and to derive the stability criterion for the corresponding explicit difference equation.
DERIVATION OF DISPERSION TERM
Let x, y be a fixed coordinate system and at any point let v be the velocity vector with magnitude v and angle, measured counter-clockwise from the x-axis. Let q be the vector which describes the rate and direction of flow of solvent due to dispersion. Consider a rotated coordinate system r, s where r is in the direction parallel to v, and s is in the perpendicular direction. Then, for an isotropic medium:
SPEJ
P. 213ˆ
Pressure-Transient Analysis for Fractured Wells Producing at Constant Pressure
Authors: Guppy K. H. , Kumar S. , Kagawan V. D. 
Published: December 2007

Summary
Past solutions to many well-test problems considered the wells to be produced at a constant rate. It has become apparent that there are many cases in which constant-pressure production is more common. Gas wells, geothermal wells, and even oil wells are operated at constant pressure during most of their producing life.
Constant-pressure well-test data for fractured wells are commonly analyzed using type-curve-matching techniques that may result in nonunique solutions. By the use of a semianalytic model, a set of correlations has been developed that reduces the nonuniqueness problem, as well as accounts for well-test data in which the well is produced at high rates.
When applied to high-flow-rate wells, this technique uses the bilinear flow period to determine an apparent fracture conductivity for constant-pressure drawdown or buildup tests. These apparent values can be corrected to true conductivities by the use of correlations presented in this study. These relationships were derived through computer simulation of a wide range of possible situations.
In summary, this paper presents for the first time a technique that analyzes buildup and drawdown data from wells produced at constant pressure with turbulent flow in the fracture. Two example applications, one for buildup and one for drawdown, are included to demonstrate the use of these techniques.
Summary of The Alcohol Slug Process for Increasing Oil Recovery
Authors: Gatlin Carl , Slobod R.L. 
Published: December 2007

The primary purpose of this investigation was to define the basic mechanism of the miscible displacement of oil and water from porous media by various water-driven alcohol slugs. The first portion of this investigation deaIt with use of a single alcohol (isopropyl) as the slug material. In later studies two distinct process variations were developed, wherein the total alcohol slug consisted of two or more slugs of different alcohols. The first of these utilized methyl alcohol and isopropyl alcohol, while the second variation used normal butyl alcohol and methyl alcohol as the composite slug. These techniques were shown to have distinct advantages over the simple, onealcohol process and represent an important extension of the original process.
The porous medium used in this study was I-in. diameter, 100-ft long, unconsolidated core. The porosity of this system was 35 per cent, and the permeability was approximately 4 darcies. Total pore volume of the core was 5,700 cc. All displacements were conducted at an injection rate of 5 to 6 cc/min, which corresponded to a frontal advance of 5 to 6 ft/hr. Most of the alcohol slug runs were initiated in a previously waterflooded system; however, several were conducted at irreducible water saturation. The oils used were naphtha, SoItrol-C and Kendex 0837, having viscosities of 0.52, 1.5 and 16 cp at 20°C, respectively. Kendex 0837 was used in only one run. Individual displacements were conducted by injecting the desired size and type of alcohol slug, which was then driven or displaced in turn by water. The basic data obtained from each run were the composition-time histories of the effluents. From these data it was possible to study the displacement mechanism and to determine the oil recovery. Data from 30 such runs were obtained.
In the first series of runs, isopropyl alcohol (IP A) was used as the alcohol slug. This alcohol is completely miscible with either oil or water; however, miscibility of the three-component system (oil-water- IP A) requires a relatively high concentration of IP A. Hence, the displacement is not of the miscible type unless the IP A content is maintained above some critical value. Slug volumes ranging from 8 to 16 per cent of total core pore volume were used in several runs in both the naphtha and Soltrol-C systems. Complete (100 per cent) naphtha recovery from a previously waterflooded core required a 13.5 per cent IP A slug. Complete SoItrol recovery required a 17 per cent slug under the same conditions.
Simulation of Gas/Liquid Flow in Slug Catchers
Authors: Bos A. , du Chatinier J. G. 
Published: December 2007

Summary
For the optimization of existing multiple-pipe-type slug catchers and the development of novel configurations, small-scale model tests are used that use a two-liquid system with a density ratio representative of that of the gas/liquid phases in practice. The technique has been validated by field tests with an existing slug catcher.
Solutions of Heat- and Fluid-Flow Problems in Naturally Fractured Reservoirs: Part 1 – Heat-Flow Problems
Authors: Satman A. 
Published: December 2007

SummaryThis is the first of two papers concerning the solution of heat- and fluid-flow problems in naturally fractured reservoirs. It deals with the temperature behavior of a naturally fractured reservoir. The naturally fractured reservoir model used assumes unsteady-state heat transfer between the matrix and fracture systems. The model consists of a production (or injection) well fully penetrating a reservoir containing equally spaced horizontal fractures.The problem of hot- or cold-water injection into a naturally fractured reservoir is considered, and a solution describing the temperature distribution in such a reservoir is given that can be used to locate the thermal front and to estimate the reservoir volume affected by the injection process. It also has application in estimating the amount of heat that can be extracted from a geothermal reservoir as the result of a reinjection process. The results of a field test support the validity of the model.
Formation Damage Tests of High-Density Brine Completion Fluids
Authors: Morgenthaler L. N. 
Published: December 2007

Summary
Laboratory core flow tests were conducted to assess the formation damage potential of brines with densities between 13.4 and 19.2 lbm/gal [1606 and 2301 kg/m3]. Unfavorable fluid/rock interactions are not evident. Recovery of oil permeability is slow but complete, in agreement with established displacement theories. Observed damage effects are the result of the instability of the brine or incompatibility with water in the cores. The effectiveness of ZnBr2 in preventing impairment suggests acid-soluble impairing materials.
Multiple-Rate Analysis for Pressure-Buildup Tests in Reservoirs With Tectonic, Regional, and Contractional Natural Fractures
Authors: Aguilera Roberto 
Published: December 2007

Summary
Approximate solutions of radial flow theory are presented for pressure-buildup analysis in naturally fractured reservoirs with tectonic, regional, and contractional fractures. The solutions allow handling of variable rates before shut-in, as well as unsteady-state interporosity flow. Although approximations, these solutions are apparently satisfactory for most cases of practical interest.
Effects of Acids on Gravels and Proppants
Authors: Cheung S. K. 
Published: December 2007

Summary
The effects of acids on the integrity of gravels and proppants should be considered in acid treatments. This paper reports on the influence of acid type, acid concentration, and contact duration on the acid solubility of five sands and bauxitic materials. The effects of the acids on the mechanical strength and the size distribution of the solids are determined. We found that intermediate-density and low-density bauxites (IDB and LDB) are very soluble in HF acid and that sintered bauxite is weakened by HF acid.
Engineer's Oil, A Challenge and An Opportunity
Authors: Bell John S. 
Published: December 2007

Introduction
In recent years, especially with the advent of the space age, attention has been focused on man's accelerating technological progress. The great majority of this progress has come in the last 100 years, and each generation has seen more progress than the last, Because the petroleum industry has played a vital part in providing the stimulus for this pattern and has continued to keep pace with man's ever increasing demand for energy, we have good reason to be proud of our industry.
However, in providing for America's future progress, which is largely dependent on an abundance of low cost energy, technological advances in the domestic oil industry far greater than in the past will be required. Our engineers have the challenge-the opportunity-to provide these advances.

Present Status of the Industry
As the domestic oil industry enters its second century, it is beset by problems of great magnitude. The threat to our continued growth and prosperity is probably greater today than at any other time in our colorful history. The total result of all our problems is demonstrated by the decline in rate of return on investments from 27.9 per cent in 1948 to 10.2 per cent in 1958. Investors in our industry today are receiving only about one-third the yearly income per dollar invested that they did just 10 years ago. Both the ability and willingness of investors to furnish the risk capital for continued expansion and growth is threatened, This decreased rate of return results from a combination of low production rates, rising costs and lagging prices.

Investments and Production
The domestic industry made capital expenditures of more than $40 billion to expand resources between 1948 and 1958 exclusive of refining and marketing expenditures. Close to 500,000 wells were drilled, reserves of 30 billion bbl were added, and producing capacity was increased by more than 4 1/2 million B/D. The oil industry had produced at near capacity during 1948, and the outlook was for a continued increase in demand.
Proration and Well Spacing in Texas
Authors: Decker Harold 
Published: December 2007

Introduction
In determining proper well spacing today we must consider the effect worldwide overproduction of crude oil will have on the oil producer in Texas both today and in the future. No longer can a producer here expect to enjoy high allowables, nor have any assurance that the price of his oil will be stabilized. We have seen both low allowables and an erosion of the price level.
With this overproduction of crude oil seeking a market, most of the foreign crude is far cheaper to produce than the oil found in Texas. In fact, oil is cheaper to produce in many states in the United States than it is in Texas because of higher allowables or no proration laws. In effect, Texas is holding an umbrella over the heads of our neighbors.
In addition, we find that we are competing with ourselves in that our gas production is taking away our oil markets. As you are all aware, the demand for gas is expanding at a much greater rate than the demand for oil-in some instances because gas is cheaper on a Btu basis and in other instances because consumers are willing to pay a premium price.

Foreign Production - World Oil Market
The Chase Manhattan Bank in its "Monthly Review of the Petroleum Situation" for July, 1959, made the following observation regarding gas:
As the expansion of gas shrinks the market for fuel oils, requirements for crude oil are lessened. And that reduces the incentive to search for new reserves. As the process continues, producers may increasingly shift their operations to foreign areas where the combination of economic factors may look relatively better. Exploratory dollars spent abroad won't find reserves in this country - neither crude oil nor natural gas. This trend, already in evidence, if carried to the extreme, could lead to a deficiency in the United States of both oil and gas reserves. Once that happens, it is doubtful that petroleum would continue to be available at bargain prices.
For Texas production to compete with oil from the Near East, where wells produce 5,000 B/D, we must work toward reducing our individual well costs and producing new wells at higher daily rates.
Capillary Pressures and Gas Relative Permeabilities of Low-Permeability Sandstone
Authors: Ward Jill S. , Morrow Norman R. 
Published: December 2007

SummaryUse of a high-speed centrifuge for capillary pressure measurements on low-permeability sandstones has been investigated. Curvatures for air/brine and air/decane displacements are compared. Capillary pressures of up to about 800 psi [5516 kPa] for gas displacing brine were extended over an order of magnitude by measurement of isotherms for desorption of water, Capillary pressures measured by high-speed centrifuge merged satisfactorily with results derived from the desorption isotherms. No distinct irreducible water saturation was observed. Permeabilities to gas at various levels of water saturation were also measured and found to be generally consistent with previous relative-permeability measurements.
A Comprehensive Fracture Diagnostics Experiment: Part 1—An Overview
Authors: Fitz-Patrick R. P. , Karr G. K. , O'shea P. A. 
Published: December 2007

Summary
A comprehensive field fracture mapping experiment was performed in 1983-84 in Mounds, OK, south of Tulsa. The target zone was the Skinner sandstone, a deltaic formation roughly 80 ft [24 m] thick found at a depth of 1,020 ft [311 m]. The first two phases of testing—extensive prefracture testing—included in-situ stress tests and minifracture treatments designed to extract the maximum amount of information about the possible orientation and azimuth of the hydraulic fracture to determine the optimum experimental procedure for the final stage of the tests, in which a fracturing treatment with a magnetized proppant would be performed. The primary goal of the experiment was to measure the transport characteristics and final distribution of the magnetic proppant with surface and borehole magnetometers. Secondary goals included extensive data acquisition to determine fracture geometry by different methods, including various types of seismic monitoring and tiltmeters. This paper, an overview for the entire experiment, focuses on the role the first two phases of the test played in the experimental design for the final phase, explains the nature of the fracture diagnostic procedures used, and summarizes the operations performed and the results obtained during the three phases of the testing. Where appropriate, conclusions regarding the degree of success of the different diagnostic methods and their potential applicability at more commercial depths are discussed.
A Comprehensive Fracture Diagnostics Experiment: Part 2— Comparison of Fracture Azimuth Measuring Procedures
Authors: Smith M. B. , Ren N.-K. , Sorrells G. G. , Teufel L. W. 
Published: December 2007

SummaryA great deal of effort has been devoted to finding geophysical techniques for measuring the hydraulic fracture azimuth. This paper discusses a comparison of seven different measurements to determine the azimuth in a sandstone formation at a depth of 1,050 ft [320 m]. The azimuth was determined as N95E, but significant differences existed between some of the results. This is of fundamental importance because in developing new measurements, the limits of these must be found and honored.Of particular interest are the results from microseismic monitoring. The lack of results suggests that remote (e.g., surface) monitoring for seismic events may be impractical for normal, sedimentary, hydrocarbon-bearing formations.
Effect on Gas Proration of Recent Special Orders
Authors: Cameron John S. 
Published: December 2007

Introduction
Natural gas is no longer the undesirable, troublesome by-product of oil production that it was just a few years ago. Table 1, a summary of Texas gas production from 1936 to 1958, highlights the tremendous increase in Texas gas production since World War II. Texas produced 6.05 trillion cu ft of gas in 1958, and this gas production is paying the way for many operators during the current low oil flow days. Gas proration is becoming more important as Texas gas production increases and should be generally understood by all producers and purchasers of gas of Texas. New special orders, issued since 1955, are explained in the paper.

Texas Railroad Commission's Duties
The Texas Railroad Commission's basic duty in gas proration is to determine the market demand for gas from a field, then to grant that demand as the field allowable in such manner as to allow each well its ratable share. The Commission is required by statute (Article 6008, Section 1 of the Revised Civil Statutes of Texas) to prorate and regulate gas production in such manner thatboth public and private interests will be protected from waste,correlative rights will be protected, andratable take will be obtained from all wells producing from a common reservoir.
The present basic method used to determine the market demand in Texas gas fields is the monthly nominations from all producers in a field. Each gas reservoir is prorated separately in Texas, and nominations are required from each producer in the reservoir. However, past experience has clearly shown that these nominations do not always accurately indicate the true market demand in a field. Adjustments are necessary to keep the nominations and the actual reported production of each field in balance.
The Commission adds the nominations from each producer to determine the market demand for that month; then this demand is adjusted by the difference between the total nominations and the actual production from that reservoir for the third previous month. The nomination and production for the third previous month must be used because monthly gas reports (Form 3–266-A) are not required until the last day of the month following the month for which the report is made. For example, in preparation of the gas schedules for October, the difference between the July nominations and July production is applied against the October nominations to obtain the October allowable for a field. A monthly gas schedule is issued for each prorated gas reservoir in Texas on the first day of each month showing the monthly allowable in thousands of cubic feet of every gas well in that reservoir.
History Matching by Spline Approximation and Regularization in Single-Phase Areal Reservoirs
Authors: Lee Tai-yong , Kravaris Costas , Seinfeld John H. 
Published: December 2007

Summary
An automatic history-matching algorithm is developed from bicubic spline approximations of permeability and porosity distributions and from the theory of regularization to estimate permeability or porosity in a single-phase, two-dimensional (2D) areal reservoir from well pressure data. The regularization feature of the algorithm, the theoretical details of which are described by Kravaris and Seinfeld, is used to convert the ill-posed history-matching problem into a well-posed problem. The algorithm uses Nazareth's3 conjugate gradient method as its core minimization method. A number of numerical experiments are carried out to evaluate the performance of the algorithm. Comparisons with conventional (nonregularized) automatic history-matching algorithms indicate the superiority of the new algorithm with respect to the parameter estimates obtained. A quasioptimal regularization parameter is determined without requiring a priori information on the statistical properties of the observations.
Oil Show Detection by C5+ Hydrocarbon Mud Logging
Authors: Dembicki Harry 
Published: December 2007

Summary
Hydrocarbons between C5 and C30 in drilling mud can be detected and analyzed by a combination of thermal extraction and gas chromatography. This information about the heavier hydrocarbons can be used to locate or to confirm the presence of liquid-hydrocarbon-filled reservoirs and to give a preliminary assessment of the types of hydrocarbons present. The technique is intended to supplement existing mud-gas logging and electrophysical logs for formation evaluation.
Deepwater Drilling and Production Articulated Column: Water Depths of 1,150 ft
Authors: Baduel F. A. , Figenschou A. 
Published: December 2007

Summary
An articulated tower for drilling and production in the Norwegian Sea in water depths of 1,150 ft [350 m] is presented. The main features are production trees at the deck level; a 19,000-ton [17 000-Mg] deck payload; limited motions; a steel structure, including main float and lattice; low-stressed mechanical articulation with antitorque device; and controlled bending risers.
This extensive study has considered in detail the behavior in extreme conditions, the fatigue of main structural parts and risers, operating procedures, fabrication, and installation. General results are given concerning behavior, structural design, articulation, bending riser, fabrication, and installation. A fabrication and installation schedule is also given.
Adaptive Implicit Methods Applied to Thermal Simulation
Authors: Behie G. A. , Forsyth P. A. , Sammon P. H. 
Published: December 2007

Summary
The application of adaptive implicit methods to a dead-oil steam simulator is discussed. Various test results are presented. The adaptive implicit method works well on thermal problems, demonstrating a 30 to 50% computing time reduction compared with a fully implicit solution technique, while giving essentially the same results.