bluuebunny/crossref_metadata_2025_split huggingface dataset:
Porosity and Permeability of Eastern Devonian Gas Shale
Authors: Soeder Daniel J. 
Published: December 2007

Summary
High-precision core analysis has been performed on eight Devonian gas shale samples from the Appalachian basin. Seven of the core samples consist of the Upper Devonian Age Huron member of the Ohio shale, six of which came from wells in the Ohio River valley, and the seventh from a well in east-central Kentucky. The eighth core sample consists of Middle Devonian Age Marcellus shale obtained from a well in Morgantown, WV.
The core analysis was originally intended to supply accurate input data for Devonian shale numerical reservoir simulation. Unexpectedly, the work has identified a number of geological factors that influence gas production from organic-rich shales. The presence of petroleum as a mobile liquid phase in the pores of all seven Huron shale samples effectively limits the gas porosity of this formation to less than 0.2%, and gas permeability of the rock matrix is commonly less than 0.1 μd at reservoir stress. The Marcellus shale core, on the other hand, was free of a mobile liquid phase and had a measured gas porosity of approximately 10%, and a surprisingly high permeability of 20 μd. Gas permeability of the Marcellus was highly stress-dependent, however; doubling the net confining stress reduced the permeability by nearly 70%.
The conclusion reached from this study is that the gas productivity potential of Devonian shale in the Appalachian basin is influenced by a wide range of geologic factors. Organic content, thermal maturity, natural fracture spacing, and stratigraphic relationships between gray and black shales all affect gas content and mobility. Understanding these factors can improve the exploration and development of Devonian shale gas.
Probable Pattern of United States Petroleum Supply
Authors: Hill Kenneth E. 
Published: December 2007

Introduction
To render an intelligent judgment on the future of the petroleum industry, it is necessary to look ahead for as long a time as feasible, even though forecasting always is fraught with danger. It particularly is useful to study the outlook for the United States petroleum industry, because it is not only the largest producer, but also the consumer of over one-half of all the petroleum produced in the world. Because of this dominant position, the U.S. price structure-particularly for crude continues to be the principal influence on prices for both crude and crude products throughout the world. Therefore, it is quite important to focus attention on the long-range outlook for petroleum demand in the U.S. and on the probable sources of supply.

Demand
It now is becoming apparent that U.S. consumption of petroleum will grow less rapidly in the future than during the first postwar decade when it averaged 5.8 per cent per annum. This appears probable principally because of several factors:the impact of cheaper natural gas on petroleum consumption,a slower rate of industrial expansion anda slower rate of growth in gasoline use as a result of compact cars and congested highways.
The consensus of most observers leans toward a rate of about 4 per cent for the next few years, and then a slow decline.
In this analysis, a simple expedient has been used-the assumption of constant increments in demand each year. Thus, for the next few years, an increment of 400,000 B/D is expected, equal to a growth rate of about 4 per cent each year. During the latter part of this decade, consumption should increase by 450,000 B/D each year. By 1970, the increment likely will be 500,000 B/D. By 1975, domestic demand for petroleum liquids will total approximately 17 million B/D. This represents an increase of about 7 million bbl (or 70 per cent) during the 15-year period, or an average of about 3.6 per cent per annum.
During the same time, natural gas demand (which currently supplies about 27 percent of our energy needs) should continue to grow at a faster rate than petroleum at an estimated rate of about 5 per cent per annum. As has been pointed out many times, this is a mixed blessing because natural gas does reduce the demand for petroleum. Otherwise, crude-oil production would be larger relative to capacity than herein estimated, thus accelerating the time when domestic production would reach a peak and begin to decline.
Pressure Distribution in Three-Dimensional Hydraulic Fractures
Authors: Vandamme L. , Jeffrey R. G. , Curran J. H. 
Published: December 2007

SummarySummary. Stress intensity factors, calculated along the edge of an elliptic fracture with a three-dimensional (3D) coupled hydraulic fracturing model, differ significantly from those that arise from a uniform pressure within the fracture. Interactions between the two branches of a T-shaped fracture are shown to affect the geometry of the overall fracture.
Measurement While Drilling - A New Tool (includes associated papers 15328 and 15343 )
Authors: Fontenot John E. 
Published: December 2007

Definition
Measurement while drilling (MWD) is the downhole measurement of important parameters and (in most cases) the simultaneous transmission of those measurements to the surface while drilling.

Need for MWD
In the past, hole-making and formation evaluation processes have been accomplished with different technologies, separated in time. Drilling (hole-making)is a complicated technological process with many uncertainties. Ignorance of what is taking place downhole during this process has caused it to be viewed more as an art than as a science. The most important parameters controlling this process are the physical properties of the formation (and the pore fluid)being drilled, which are largely unknown at the time of drilling.
The big mistakes that involve the loss of well control (blowouts) are well known. The many "small" mistakes (kicks, lost circulation, stuck pipe, lost cones, twistoffs, etc.) are not so well known, but cost considerable time and money. The conventional (wireline) formation evaluation process, while very important to the geologist, the petrophysicist, and the reservoir engineer, is also very expensive in terms of rig time and trouble cost.

History
The first U.S. patents and technical papers on MWD appeared in the early 1930's. The first practical approach that resulted in technical success was J.J. Arps' mud pulse system that made its debut in the 1950's. In the late 1960's, Exxon and Texaco experimented with downhole recording while drilling. The lack of high-density electronics packaging, a suitable memory medium, and the ability to ruggedize the systems adequately made them unattractive for extensive use.
As a result of the efforts of SNEA (Elf Aquitaine)and Raymond Engineering, and with the financial assistance of the U.S. DOE, Teleco introduced the first commercial MWD system in 1978. At the current time, many companies are investing in this technology, while eight offer commercial services.

Data Rate Requirements
When designing or selecting an MWD system for use, one must specify the types of downhole information desired and the measurement rates needed. Some information is needed on a "time(ly) basis" and other on a "footage basis." To convert from a time base to a depth base, the drilling rate must be known. A curve of average penetration rate as a function of depth that is typical of the Gulf of Mexico was used to prepare Fig.
It provides a rough guide as to the suitability of various mud-pulse data rates for providing multiple-service MWD.
A Rule-Based System for Well Log Correlation
Authors: Startzman Richard A. , Kuo Tsai-Bao 
Published: December 2007

Summary
Computer-assisted approaches to well log correlation are of interest to engineers and geologists for two reasons. In large field studies, a computer can be used simply to reduce the time required to correlate zones of interest. It is also possible that computer-assisted correlations may suggest zonal matches of interest and originality that might not have been considered. This paper presents a new approach to the computer-assisted log correlation. Geologic horizons are correlated between wells by use of an artificial intelligence rule-based technique. Using the symbol-manipulation capabilities of a computer language called List Processing (LISP), we developed a prototype rule-based system that (1) has symbolic representation of log data, (2) recognizes log shapes from traces, (3) identifies geologic zones from a sequence of shapes in a log, (4) characterizes the zones, (5) correlates zones from well to well with a set of "if/then" type of rules, and (6) uses a forward-chaining inference scheme to execute the rule base. The purpose of this paper is to describe the use of the LISP language and the methodology involved in the development of this system.
Two-Point Determinations of Permeability and PV vs. Net Confining Stress
Authors: Jones Stanley C. 
Published: December 2007

Summary
Empirical equations are presented that accurately fit permeability, PV, or porosity data vs. net confining stress. Each of these equations has four adjustable parameters. With little loss of accuracy, however, two of the coefficients can be preset. Consequently, permeability, PV, or porosity measurements need to be made at only two confining stresses—e.g., at 1,500 and 5,000 psi [10.3 and 34'.5 MPa] to define the stress dependence within close tolerances completely.
With the techniques described, economical measurements of these stress-dependent properties can be made on a routine basis. The results can be used to calculate PV compressibility and to estimate productivity declines resulting from permeability reduction as deep, high-pressure reservoirs are drawn down.
Factors Affecting the Equivalency of Different Capillary Pressure Measurement Techniques
Authors: Omoregie Zuwa S. 
Published: December 2007

SummaryThe results of a laboratory investigation of the effects of some factors that affect the equivalency of different drainage capillary pressure measurement techniques are presented. These factors are Bond number, clay alteration by sample drying, wettability, equilibration, sample orientation, and overburden pressure. The results, among other things, suggest an extension of the range oof validity of liquid/liquid centrifuge tests. A method of estimating contact angles of weakly wetting systems with capillary pressure data is presented.
Measurement and Correlation of Diffusion Coefficients for CO2 and Rich-Gas Applications
Authors: Renner T. A. 
Published: December 2007

Summary
A novel in-situ method for measuring molecular diffusion coefficients of CO2 and other solvent gases in consolidated porous media at high pressure has been developed and is described. This technique is unique because visual observations and measurements of composition are not required. Experimental diffusion coefficients are reported for CO2 in decane up to 850 psia [5.86 MPa], for CO2 in 0.25 N NaCl brine up to 850 psia [5.86 MPa], and for ethane in decane up to 600 psia [4.14 MPa]. All tests were conducted in Berea cores saturated with liquid phase at 100°F [311 K]. Cores were oriented both vertically and horizontally to assess the effects of gravity-induced convection on the observed mass transfer. The experimental diffusion coefficients obtained from this study have also been correlated, together with literature data for methane, ethane, and propane, as a function of liquid viscosity and thermophysical properties of the diffusing gases.
Vapor-Density Measurement for Estimating Minimum Miscibility Pressure
Authors: Harmon Richard A. , Grigg Reid B. 
Published: December 2007

Summary
A rapid experimental method is described that uses the solvency (density) properties of CO2 and the actual stock-tank oil to determine the minimum miscibility pressure (MMP).
The "vapor-density" method directly measures the density of the injection-gas-rich upper phase in contact with the crude oil as a function of pressure. This measurement correlates very well with the MMP from slim-tube experiments below about 110°F [43°C] and may be extended to higher reservoir temperatures.
Analysis of Mudcake Structures Formed Under Simulated Borehole Conditions
Authors: Hartmann Albert , Özerler Mustafa , Marx Claus , Neumann Hans-Joachlm 
Published: December 2007

SummaryTiny pieces of filter cake were shock-frozen and broken while immersed in coolant. The specimens were studied with scanning electron microscopy (SEM) in both freeze-dried and frozen-hydrated stages. These techniques were used to show that the original structure of the filter cake is preserved. The investigation covered filter cakes of four different drilling fluids with respect to fluid loss data and thermal and chemical degradation. Honeycomb structures of bentonite containing drilling fluids were also found in the resultant filter cakes. The investigation showed that gel strength of the drilling fluid exerts a considerable influence on dynamic filter-cake structures.
The Influence of Sample Size and Permeability Distribution on Heterogeneity Measures
Authors: Jensen Jerry L. , Lake Larry W. 
Published: December 2007

Summary
This study evaluates the influence of sample size on the Dykstra-Parsons and Lorenz measures of heterogeneity. Because either coefficient is &lt;&gt;determined for a reservoir from a finite number of data, only an estimate is made of the true coefficient. We show that, on average, the estimate is less than the true value. We give the relationship between estimate error and number of samples and show how significant errors may arise when too few data are used.
The influence of the permeability distribution on heterogeneity measures is also studied. We show that a variety of distributions exhibiting different reservoir performance can have the same Dykstra-Parsons coefficient.
We propose a heterogeneity measure that includes an indication of the permeability distribution. The new measure requires fewer data than the Dykstra-Parsons estimator. The relationships between the new measure and the Dykstra-Parsons and Lorenz coefficients are given.
Experimental Studies on the Waterflood Residual Gas Saturation and Its Production by Blowdown
Authors: Flshlock T. P. , Smith R. A. , Soper B. M. , Wood R. W. 
Published: December 2007

Summary
Experiments performed on long sandstone cores determined the waterflood residual gas saturation and the mobilization of this trapped gas by reduction of pressure. The trapped gas apparently did not become mobile immediately as it expanded: the gas saturation had to increase appreciably to a critical value for gas remobilization. This new finding has unfavorable implications for possible processes to increase liquids recovery from gas-condensate reservoirs and for enhanced recovery from gas reservoirs invaded by water.
New Concepts for Helical Buckling
Authors: Mitchell R. F. 
Published: December 2007

Summary
An approximate analytic solution for the helical buckling of tubing with weight has been determined. This solution has good accuracy except near the neutral point. The solution used by Lubinski to solve the helical-buckling problem is shown to be a special case of this new analytic solution. It is generally accepted that Lubinski's solution is a good approximate solution, but the range of applicability has been unknown because the approximations used in its derivation were not well understood. In this new solution, the approximations are explicit and an accuracy criterion is established. Initial conditions at the packer are investigated and their effects on the solution are described. Finally, the effect of this solution on tapered strings is described, and a new approximate buckled solution for tapered strings is presented. This analysis puts the Lubinski solution in a technical context that allows such further developments as inclined wellbores and friction.
Analyses and Applications of Pressure, Flow Rate, and Temperature Measurements During a Perforating Run
Authors: Tarlq Syed M. , Ayestaran Luis C. 
Published: December 2007

Summary
Perforating technology has undergone significant advances during the last decade. Tubing-conveyed perforating, under-balanced perforating, high-shot-density guns, better shaped charges, and improved gun systems have contributed to safer operations and improved productivity of the perforated completions. A recent development described in this paper is a perforating tool that makes real-time downhole measurements [including pressure, flow rate, temperature, gamma ray, casing-collar locator (CCL), and cable tension] during a perforating run and can selectively fire a number of guns at different depths or times. In addition to providing better control of the perforating process, the simultaneous downhole measurements can provide in a single trip a production log, conventional well tests before and after perforating, and a fill-up or slug test soon after perforating for underbalanced conditions. Thus, the completion can be evaluated in real time and any needed remedial reperforating can be performed while the gun is still in the hole. Other applications include limited-entry perforating, monitoring of bottomhole pressure (BHP) during minifracture jobs, better depth control with a gamma ray detector, fluid-level monitoring, and underbalance control. The applications of these measurements, with field data obtained with the Measurement While Perforating (MWPSM) tool, are the subject of this paper. Examples show the capabilities and the versatility of the MWP tool.
Transient Analysis of Acoustically Derived Pressure and Rate Data
Authors: Kabir C. S. , Kuchuk F. J. , Hasan A. R. 
Published: December 2007

Summary
A pressure-buildup test conducted on a sucker-rod pumping well is often distorted by long-duration wellbore storage. In fact, this distortion could be so severe that even a week′s shut-in period may not allow a semilog analysis. A longer shut-in period becomes economically discouraging because of lost production.
Low energy and low transmissivity in the reservoir, coupled with increased fluid compressibility, contribute to this long-duration storage phenomenon. One way of reducing the storage effect clearly lies in the simultaneous analysis of downhole pressure and flow rate, estimated from casinghead pressure and rising annular liquid-level measurement made by acoustic well sounding (AWS). Ascertaining the quality of the indirectly measured pressure and rate data constitutes one of the objectives of this study.
Several methods exist to translate the AWS measurement to downhole pressure and rate data for the subsequent transient analysis. We show that even an empirical hydrodynamic correlation provides satisfactory transient-pressure/flow-rate data for convolution and deconvolution analyses for moderate pumping-liquid columns. When long annular liquid columns are encountered, translating the AWS measurement with a mechanistically based hydrodynamic model appears to be a prudent approach.
Interpretation of several transient tests show that automated convolved-type-curve or history matching of field data is a powerful tool for reservoir-parameter (total mobility, skin, fracture half-length, and storage coefficient) estimation. Use of downhole rate for the convolved type-curve matching reduces the variable storage coefficient by several orders of magnitude, thereby enhancing the quality of the estimates. Deconvolution of downhole pressure and rate data and the pressure-derivative approach significantly aided in well/reservoir flow-model identification.
A simple algorithm for computing the Laplace transform of the wellbore pressure for an infinite-conductivity vertically fractured well in an infinite reservoir is developed in this work for a rapid, iterative-type computation used in automated convolved-type-curve analysis.
Stability of Boreholes Drilled Through Salt Formations Displaying Plastic Behavior
Authors: Infante E. F. , Chenevert M. E. 
Published: December 2007

Summary
This paper presents a mathematical and laboratory analysis that provides solutions to the problem of plastic flow of salt formations into wellbores. The paper predicts how the salt will flow and what type of mud might be used to control such flow for various well conditions. In the mathematical analysis, it is assumed that the incipience of plasticity in the formation is regulated by the level of octahedral shear stress and that the formation is neither permeable nor porous, but homogeneous and isotropic. The stress distribution in the neighborhood of the borehole is studied, and conditions under which this distribution is elastic, elastoplastic, or plastic are determined. Equations are derived that, in terms of two constants of the formation material, yield, and the limit of elasticity. Factors calculated include the radius of the plastic front and the percent of the borehole-diameter shrinkage as a function of mud weight used. This study was prompted by past failures in drilling through the Louann salt formation at depths of 12,500 to 14,000 ft [3810 to 4270 m], a formation that exhibits rapid plastic flow at low mud weights and at the temperatures and pressures encountered. The techniques presented were applied to subsequent drilling of this salt section, and the zone was penetrated without the problem of plastic flow. Salt-property constants were developed at elevated temperatures and pressures for the Louann salt formation by use of the triaxial test cell. Data are presented for elastic, plastic, and creep deformation of salt for pressures to 13,200 psi [91 MPa] and temperatures to 350°F [177°C]. Nomographs are also presented to facilitate the rapid determination of salt behavior. For a given depth and temperature, it is possible to specify a mud weight so that the salt will behave either elastically, in creep flow, or plastically. If plastic flow is predicted, the amount of borehole-diameter reduction is specified. Although this study focuses on the Louann salt section, we believe that the results apply equally well to any other salt section with physical constants similar to those in the Louann salt.
Depletion Performance of Volumetric High-Pressured Gas Reservoirs
Authors: Begland T. F. , Whitehead W. R. 
Published: December 2007

Summary
A method to predict the percent recovery of volumetric, high-pressured gas reservoirs from the initial pressure to the abandonment pressure with only initial reservoir data is presented. This method can also be used with early-life production data to predict the initial gas in place. The method is based on an incremental solution to the general material-balance equation. All parameters in the material balance are pressure-dependent and are recalculated for every 100-psi [690-kPa] drop in reservoir pressure. Procedures were developed to calculate these parameters with correlations and data available in the literature. PV compressibilities, formation-water compressibilities, and gas compressibility factors were determined for temperatures and pressures ranging up to 400°F and 20,000 psia [204°C and 137.9 MPa], respectively. The pressure dependency of the PV compressibility and the formation-water compressibility is a unique feature of this model.
The reservoir depletion model presented here was applied to a field example, as were three published techniques for determining reserves in abnormally pressured reservoirs. When predictions of initial gas in place were compared, the reservoir depletion model yielded a more accurate value than the other techniques.
Obtaining Structural and Stratigraphic Dip Information Using Segmentation Trees and Optimization
Authors: Kerzner Mark G. 
Published: December 2007

Summary
A new method of dipmeter computation is described that is based on formalizing and implementing some of the rules of optical dipmeter correlation. The new techniques used for this are segmentation trees and hierarchical, multilevel optimization. Use of this method results in precise definition of dip information on both structural and stratigraphic levels.