bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Response of Interwell Tracer Tests in Watered-Out Reservoirs
Authors: Hagoort Jacques 
Published: December 2007

SUMMARY
A study has been made of the response of production wells to the injection of a tracer pulse into an injector in watered-out reservoirs. Two response functions can be distinguished: (i) the tracer production rate and (ii) the cumulative tracer recovery both as functions of time. It is shown that the tracer response to pulse injection can be obtained from the results of a unit-mobility-ratio, equal-density miscible displacement. The cumulative tracer recovery is identical with the production rate of the displacing phase. The tracer production rate follows from differentiation of the production rate of the displacing phase with respect to time.
For some simple flow systems, analytical solutions are presented that bring out the general features of the responses of interwell tracer tests. Linear flow solutions indicate the effect of longitudinal mixing to be negligible, whereas transversal mixing is important in layered reservoirs only if the individual layers are relatively thin (cm-dm scale). Solutions for a homogeneous two-spot show the effect of a pattern. The production-rate response is slide-shaped: a sudden rise followed by a fairly extensive fall-off period. This fall-off period becomes shorter for more linear patterns. In stratified reservoirs each layer produces its own ‘slide’ response. The responses of the less prolific layers, however, may be completely swamped by those of the more prolific layers.
A procedure is indicated to model ‘single-colour’ and ‘multi-colour’ field tracer tests with the help of a conventional black oil simulator. It is based on the mathematical similarity that exists between two-phase immiscible flow and two-component miscible flow. For accurate simulation results a fine grid system (at least seven grid blocks between injector and producers) must be employed.
The study may find application in the planning, design and interpretation of field tracer tests in watered-out reservoirs. The results of this study also apply to tracer tests in gas cycling projects.
Experiences with Natural Gamma Ray Spectral Logging in North America
Authors: Fertl W. H. , Frost E. 
Published: December 2007

ABSTRACT
The last few years have brought on the inclusion of natural gamma ray spectral logging devices as an integral part of optimized wireline logging programs. Recorded in both open hole and cased hole environments, such logs have proven invaluable in solving the complex interpretation problems encountered in many wells. Interpretive concepts have advanced both at the wellsite and for detailed digital analyses at central processing centers.
Current wellsite evaluation techniques, as well as several recently developed digital interpretive methods for shaly sands and complex and fractured reservoir rocks, will be discussed. Inherent environmental constraints of natural gamma ray spectral logging devices are also highlighted.
The Impact of Common Completion and Workover Activities on the Effective Costs of Geothermal Wells
Authors: Carson Charles C. , Mansure A. J. 
Published: December 2007

ABSTRACT
Drilling and completing wells at minimum initial cost may not be the most cost effective way to exploit the geothermal resource. The impacts of completion practices on production and maintenance costs must also be considered. To evaluate alternative completion and workover technologies, a simple model has been developed that compares total well cost to total production or injection. This paper briefly discusses the model and focuses on results from its application to different completion and workover strategies.
The model development project had three aspects: 1) the establishment of a data base for the cost and effectiveness of various geothermal completion and workover activities; 2) the development of a computer model built around these data; and 3) application of the model to specific cases. The data collected include geothermal production characteristics; initial costs and effectiveness of common workover equipment and operations; the frequencies of and times required to perform work-overs; etc. The model facilitates comparisons of completion and workover alternatives. Its primary purpose is the evaluation of potential impacts of proposed geothermal completion technologies in order to aid the management and direction of the DOE/Sandia Geothermal Technology Development Program.
The results discussed include an analysis of the impact of variations in well lifetime. Additional lifetime beyond 10 to 15 years adds little value to the well. A comparison of mechanical descaling of geothermal wells to chemical scale inhibition indicates that for certain conditions chemical inhibition is more cost effective. Results of an analysis of injectivity decline are also presented, as are studies of original well cost, initial flow rate, and productivity decline for production wells. Other results involving underreaming, changing casing profiles, perforating, and hydraulic fracturing are also discussed.
Testing of Gas-Tight Joints Under Extreme Conditions
Authors: Marx Claus , Krug Gerhard 
Published: December 2007

ABSTRACT
During production from high-pressure gas wells, the casing and tubing strings are subjected to a combination of extreme loads due to internal pressure, axial loads, temperature, and sometimes bending. All loads may vary greatly during production cycles or production and shut-in periods. Testing facilities and programs are needed for evaluating the functional behavior of pipe connections during load and temperature cycles simulating actual field conditions.
The paper describes a complete testing set-up with high capacity and flexibility. The unit allows internal gas pressure up to 3500 bar, axial loads of 3000 kN, bending loads of 3600 kN, and temperatures up to 185°C at the joint.
Furthermore, the paper presents results derived from a large number of tests on tubing and casing of various sizes,grades and joints, including 2–3/8" tubing and 10-3/4" heavy wall casing.
Mathematical Modeling of Gas Field Development and Production Optimization
Authors: Zakirov S. N. , Kolbikov S. V. , Kalra S. K. 
Published: December 2007

Abstract
A complex mathematical model has been presented to analyze reservoir and production performance of gas wells and to assist management to achieve the best economic indices in the development of the field. The model was applied in one of the biggest gas fields in the USSR in Siberia - Medveje. The paper describes the numerical model of gas reservoir and algorithms describing two-dimensional areal single-phase unsteady state filtration of gas and water, respectively, in heterogeneous porous media for water drive, steady state flow of gas in each well and gas gathering system equipped with or without compressors. Algorithms to calculate optimum production rates from each well with minimum loss of formation energy have been included. The model also permits one to calculate economic indices and to evaluate reservoir parameters based on its actual performance (history matching). The results obtained for the Medveje gas field show that the model permits one to select the optimum variant of development of the gas field, i.e. maximum profit with an optimum value of the total gas recovery factor.
Applications of Foam Cement
Authors: McElfresh Paul M. , Go Boncan Virgilio C. 
Published: December 2007

ABSTRACT
Foam cement offers a versatile and economical means of cementing wells with low density, high strength material. Several common applications of foam cement are available, and these include placing strong cement across weak or highly fractured zones without losing circulation; filling vugs or porous thief zones; or simply as an inexpensive light-weight filler slurry.
The various aspects of slurry design, including their methods of determination, are discussed. It was found that thickening times could be determined directly on the foam cement in existing equipment with only minor modifications; the fluid loss and the rheology could be measured directly with no modifications; and the compressive strengths were determined in a special cell to prevent water invasion from the curing chamber. Since these parameters are determined by the nitrogen content, their relationships to density are also discussed.
Job procedures for pumping foam cement are discussed in two methods, i.e., constant nitrogen rate (variable foam density) and constant density (variable nitrogen rate). Included in this discussion is the description of an improved atomizer for generating foam cement. From yard tests utilizing field equipment, it was found that this device improved the foam stability by means of better disbursement of the nitrogen in the cement slurry. The computer program which calculates the surface gas injection rates to achieve the desired density at specified depths is discussed and evaluated. Case histories are then presented to illustrate the effectiveness and versatility of foam cement as well as its relative ease of application. The case histories deal with repairing casing leaks and lost circulation problems in weak formations.
Foamed Cement — Solving Old Problems with a New Technique
Authors: Benge O. G. , Spangle L. B. , Sauer C. W. 
Published: December 2007

ABSTRACT
A new method of combining nitrogen with an intermediate-weight cement slurry (13 to 15 1 b/gal) to generate a stable foam has solved many of the problems associated with the use of conventional lightweight cements in oil-field operations.
Foaming permits placing relatively high-strength, lightweight (6 to 11 lb/gal) cement slurries into the casing-formation annulus economically. Lightweight filler cement is often needed to provide a complete cement sheath along the length of the casing, where lost circulation is encountered or long lifts of cements are required. Various methods have been used in the past to obtain this lightweight slurry. These include the use of natural and chemical extenders, glass bubbles, ceramic bubbles and the combination of intermediate-weight cement slurries with gases. While the process of foaming cement to make lightweight slurries is not new, the technology for applying this process to oil and gas well cementing has been lacking.
The new method requires special treatment and slurry design to obtain a hydrostatically balanced slurry along the entire length of the casing, but can be performed with current equipment and field personnel. Laboratory data and case histories have been used to describe these designs. The added safety requirements which must be in effect to successfully complete this type of cementing operation are discussed.
Determination of Average Pressure in Gas Reservoirs From Pressure Buildup Tests
Authors: Ziauddin Zia 
Published: December 2007

ABSTRACT
A well known method for determination of average reservoir pressure in bounded systems from pressure buildup tests is the method utilizing the Matthews-Brons-Hazebroek (MBH) (1) functions. The MBH functions were developed using the solution of the diffusivity equation obtained by assuming viscosity compressibility product to be small and constant. The use of MBH functions for gas can produce erroneous average reservoir pressures even if the pseudo-pressure transformations are utilized. The use of pseudo-pressures still leaves the diffusivity equation as a non-linear equation. A solution of this non-linear equation provides a correction term for the MBH functions when used for gas reservoirs. This correction term takes into account the variations in viscosity compressibility product with pressure. More realistic results are obtained by using this correction term. The same correction term can also be used for modifying the various published dimensionless pressure solutions developed for the oil case, for use with problems involving real gas flow. This paper describes the method for calculating this correction term and its application.
New Approach to Casing-Lading Practice Based on Results of Oil Field Measurements
Authors: Arpashi Miklos 
Published: December 2007

SUMMARY
Increasing drilling depths and the growing ratio of natural gas fields require some modification of the theory and practice of casing landing.
Some field measurements were concluded to examine the relation between the casing landing practice, derived from theoretical considerations utilizing the theorem of elastic stability, and the actual stress/deformation behaviour of the casing string thus set.
Utilizing the measured data a new calculation method was elaborated taking into consideration the actual stress conditions and the influencing loads, further on the geotechnical conditions in Hungary.
Recovery Economics of Coalbed Methane and Cost Implications of Pipeline Hookup
Authors: Dickehuth Debra A. , Adams Margaret A. , Hayoz Fred P. 
Published: December 2007

Abstract
For Appalachian coal mines, the totaled methane emission rates exceed 180 MMCF/D, with active mines pushing deeper into virgin seams having higher relative gas contents. While most of this gas currently is vented into the atmosphere to prevent gas-related explosions, the technology exists to develop this valuable gas resource either in conjunction with mining or independently.
In 1977, the U.S. Department of Energy (DOE) began the Methane Recovery from Coal beds Project (MRCP) to characterize and help encourage utilization of this resource. Since the projects inception, TRW has been involved in the collection and analysis of data, and is in the process of forming a coherent picture of the coalbed methane resource potential for the entire Appalachian region. Preliminary analysis indicates an estimated in-place coalbed methane resource in the Appalachian Basin of up to 150 TCF. Eastern coal operators are beginning to better understand the production potential of coalbed methane. In Buchanan County, Virginia, the Island Creek Coal Company produced up to 434 MCF/d from 12 horizontal boreholes drilled into the mine face. In Alabama, U.S. Steel's mines recently began commercial production and sold 25 MMCF of pipeline quality gas in December of 1981.
This study examines the recovery economics of coalbed methane, and specifically addresses the cost implications of pipeline hook-up. An analysis which addresses the size of a project, pipeline construction costs, and anticipated contract gas price helps determine an economical project-to-pipeline hook-up distance.
Stimulation Evaluation in the Appalachian Tight Gas Sands
Authors: Charles John G. , Hydock Kevin D. , Udick Thomas H. , Hall Donald R. 
Published: December 2007

Abstract
Hydraulic fracturing is the most common method used to improve production from wells drilled into "tight" formations. Accurate fracture design is essential in order to obtain highly conductive and deeply penetrating fractures. In the past, many stimulation treatments in the northeastern United States had little basis for design. Thousands of wells have been fractured and comparative analysis of different techniques was extremely difficult. This paper attempts to evaluate fracture design in relation to tight gas sands in the northeast.
A review of the major variables affecting hydraulic fracture design is included and a discussion of three pressure transient methods used in the evaluation is presented. Pressure buildup analysis was used to determine effective reservoir permeability and pressure. Type curve matching was used to approximate fracture lengths and to predict production resulting from changes in fracture geometry. Computer reservoir simulation analysis helped in more accurately modeling the reservoir to support the production forecasting.
A case history detailing this method of evaluation in the Medina Formation is discussed. Actual field data are compared to the predicted results.
Outlook for U.S. Gas Energy, Demand, and Competitiveness
Authors: Schlesinger Benjamin 
Published: December 2007

Abstract
The gas transmission and distribution industry believes that available supplies of gas energy will range from 23 to 31 trillion cubic feet (Tcf) by the year 2000, as conventional gas production is increasingly supplemented by supplies from supplemental and non-conventional sources. Under the right set of price and regulatory conditions, gas demand can increase in the traditional heating, industrial fuel and feestock applications, as well as in such new non-traditional uses as cogeneration, natural gas vehicles and select gas use with coal. Gas prices are rising rapidly enough under the existing law between now and 1985, so that concerns of a sudden price increase after deregulation in that year may be somewhat overstated -- as long as indefinite price escalators, take-or-pay, and other issues in gas purchase contracts are fully resolved beforehand.
A Review of Marine Systems Use in Developing Alaskan Natural Gas
Authors: Hederman W. F. 
Published: December 2007

Abstract
The successful development of the major supplies of natural gas in Prudhoe Bay, Alaska was expected to follow the President's selection in 1977 of the Alaskan Highway proposal to construct a pipeline across Canada and deliver Arctic natural gas to the lower-48 states. Five years later, the proposed Alaska Natural Gas Transportation System (ANGTS) continues to encounter serious obstacles to its successful development.
Prediction Of Tracer Behavior In Five-Spot Flow
Authors: Brigham W.E. , Smith D.H. 
Published: December 2007

Abstract
Equations are developed to predict the time of tracer breakthrough, the peak concentration of the tracer, and the general form of the breakthrough curve in a 5-spot flood. It is shown that these results depend on the amount of stratification of the reservoir, the volumes injected and produced, the natural dispersion coefficient of the tracer in the reservoir, the amount of tracer injected, plus all the reservoir volume parameters (i.e. well spacing, porosity, thickness).
Many laboratory data are available on the breakthrough characteristics of a 5-spot flood, also much data is available on the natural linear dispersion coefficients of reservoir rock. To derive the equations, these data were combined and several assumptions were made. It was also necessary to graphically differentiate the breakthrough data. Thus it should be recognized that the final equations likely have some error. However, this should not invalidate their use, for the method and logic behind the derivation are sound, and thus the form of the final equations should be close to correct. In this paper, the prediction equations are used in a reverse sense. That is, the detailed tracer production history from a field test is used to estimate permeability variation in a 5-spot.

Introduction
Tracers have been used for many years in reservoir floods to help the operating engineer understand the flow characteristics. Generally this use has been entirely qualitative. The results of time-of-flight, peak concentrations at the producing wells, concentration history, and directional flow have been used only to substantiate that channelling does nor does not exist. No attempts have been made to predict quantitatively the tracer breakthrough behavior that might be expected from different reservoir characteristics.
In the past couple of years it has become apparent that some prediction technique could be well used to supplement the other tools available to the reservoir engineer. It is becoming increasingly important that maximum recovery be obtained from a flood, and any quantitative information about the reservoir can be of help in achieving this maximum. The work reported here is a step in this direction — an attempt to quantify the tracer behavior.
Equations are developed to predict the time of tracer breakthrough, the peak concentration of the tracer, and the general form of the breakthrough curve in a 5-spot flood. Tracer production history from a field test are compared to the behavior as predicted by the equations.
Investment Evaluations in Inflationary and Unstable Scenarios
Authors: Rosbaco Juan Antonio 
Published: December 2007

ABSTRACT
Two different methodologies to evaluate investments in inflationary and unstable scenarios are described. These techniques have been successfully applied, and are mainly useful because they enable changes in the inflation rate throughout the whole life of the project. These models allow us to evaluate the influence of different events on the project yardsticks. In this case, the examples presented enable us to point out some aspects related to the deferred payments.
The Development Decision: Value of Information
Authors: Warren J. E. 
Published: December 2007

Abstract
In the petroleum industry, the decision to develop newly discovered hydrocarbon resources must be made under conditions of uncertainty; i.e., with less than perfect information available. However, both the degree of uncertainty and the economic consequences which are associated with such decisions can, and do, vary widely. Of particular interest are frontier areas where either a premature or an overdue decision can jeopardize the viability of a multibillion dollar project.
Although uncertainty can always be reduced by simply buying more information--additional delineation wells, 3-D seismic surveys, extended well tests, detailed design studies, etc., there must be a point at which the cost of additional information exceeds its benefit. This paper examines the problem of determining the point at which the development decision should be made; it specifically considers the following two principal sources of uncertainty:
The estimated distribution of the hydrocarbon reserves. The cost of development--assumed to be related directly to the projected distribution of the development period.
A realistic procedure, based on the concept of the optimal development plan, is presented and discussed; criteria related to the time for decision making and to the decision itself are established; and, the real value of information is determined. Finally, to demonstrate the use of the suggested approach, a comprehensive example--typical of a frontier area--is included.