bluuebunny/crossref_metadata_2025_split huggingface dataset:
Horizontal Slim-Hole Drilling With Coiled Tubing: An Operator's Experience
Authors: Ramos A.B. , Fahel R.A. , Chaffin Michael , Pulis K.H. 
Published: December 2007

Summary
What is believed to be the first horizontal well drilled with directionally controlled coiled tubing recently was completed in the Austin Chalk formation. An existing well was sidetracked out of 4 ½ -in. casing with a conventional whip stock. An average build rate of 15°/ 100 ft was achieved in the curve, and a 1,458-ft vertical section was drilled with 2-in. coiled tubing, downhole mud motors, wireline steering tools, a mechanical downhole orienting tool, and 3 7/8-in. bits. This paper discusses the orienting and directional tools and techniques developed during this operation. It also describes improvements made for the second well.

Introduction
The Austin Chalk formation within the Pearsall field in Texas consists of a Cretaceous limestone through which production occurs from natural fractures. Drilling through these fractures requires careful preparation because the rig may encounter prolific flow of oil or complete lost circulation. During the discovery of the Pearsall field, wells were drilled vertically to the Austin Chalk. Horizontal drilling currently is the preferred technique for development of the Austin Chalk. Through horizontal drilling, a single wellbore can intersect several fractures, potentially increasing initial flow and ultimate oil recovery. Fresh water usually is used as a drilling fluid because it will control formation pressures when circulation is lost. Surface pressure containment equipment allows the flow of well fluids and gases to the surface under controlled circumstances where they are processed during drilling. In the field, this technique is commonly called "flow drilling." This method minimizes loss of drilling fluid to the formation and increases rate of penetration (ROP). The severity of either lost circulation or prolific flow can pose operational and safety problems. Loss of circulation can prevent adequate removal of drill cuttings, increasing the potential for sticking the drillstring. In addition, the logistics for providing an ample water supply in this semiarid area are complex because the large volumes required to power the downhole mud motors are lost to the natural fractures. Prolific flow from the fractures necessitates the handling of large volumes of oil and gas at pressures that can approach the limits of the surface equipment. Safely tripping into or out of the hole with drillpipe requires killing the well, which sometimes calls for the use of expensive and environmentally undesirable heavy brines. Therefore, a method of tripping while under pressure without killing the well would greatly enhance flow drilling operations. This problem was addressed by replacing the conventional drillstring with coiled tubing.
Theoretical Forces for Prescribed Motion of a Roller Bit
Authors: Biggs M.D. , Cheatham J.B. 
Published: December 2007

Abstract
This paper presents a systematic method for determining The forces on a simplified roller bit. The kinematics of an actual roller bit drilling in rock is complex; nevertheless, it is desirable to obtain an accurate analytical model. As a preliminary study, the roller bit is represented here by a preliminary study, the roller bit is represented here by a simple two-dimensional bit and the rock by a Coulomb plastic material. Results from previous work, plus plastic material. Results from previous work, plus additional assumptions, are incorporated into a computer program to determine the forces required to move the bit in a specified manner. Example problems are worked by use of this program. By problems are worked by use of this program. By studying similar but less complex drilling problems and by supporting laboratory work, one could eventually obtain an accurate analytical model for drilling an actual roller bit. This could lead to the compilation of a catalog of results that, in turn, would allow selection of the optimum drill bit for any given situation.

Introduction
The kinematics of an actual roller bit drilling in rock is complex so complex that it is not appropriate for basic analytical study. However, it is desirable to obtain eventually an accurate analytical model of rock drilling; with such a model the optimum drill bit for any given situation could be selected. As a first step toward obtaining a model, the actual roller bit is replaced by a simplified one and the rock is idealized as a more predictable material. Previous work, with appropriate modifications, has Previous work, with appropriate modifications, has been incorporated into this study. The previous work includes force-indentation studies of single teeth, and prediction of the path of fracture in both brittle and plastic stressed material. The work presented here is based primarily on a thesis.
Effect of Proppant Failure and Fines Migration on Conductivity of Propped Fractures
Authors: Gidley J. L. , Penny G. S. , McDaniel R. R. 
Published: December 2007

Abstract
Long-term conductivity testing at realistic environmental conditions has greatly improved the measurement of proppant pack permeability. However, the use of low flow rates to insure Darcy flow in such measurements has masked the total effect of failed proppant fines on proppant pack permeability. As flow rates increase, corresponding with those commonly found in the field, fines are mobilized and migrate into new positions that reduce the permeability of the proppant pack beyond that normally observed in conductivity measurements. This effect has generally been overlooked in proppant pack design.
This paper examines the extent of conductivity reduction caused by migrating proppant fines and the effect of proppant type on the extent of that reduction. The role of fines migration on the conductivity of proppant packs containing two different types of proppants, where the more capable proppant is used near the wellbore, is also evaluated.
Representative commercially available proppants, including sand, resin-coated sand, and low density ceramics are included in the study.
Shale Alteration by Water Adsorption
Authors: Chenevert Martin E. 
Published: December 2007

An adsorptional isotherm technique makes it possible to define quantitatively the hydrational tendencies of any formation, thereby eliminating the cumbersome rock classification schemes presently used in industry.

Introduction
Properties of some argillaceous rocks are known to be Properties of some argillaceous rocks are known to be altered by adsorption of water. Montmorillonitic rocks, for example tend to expand and crumble when contacted by low-salinity water.' Quantitative data are available on the behavior and properties of montmorillonitic sandstones and pure clays, but not for rocks that can be broadly categorized as shales. (A shale can be described as being fine grained, argillaceous, highly compacted, and partially dehydrated.) The purpose of this work was to observe the behavior and measure the properties of a broad range of shale types-montmorillonitic, illitic and chloritic-when exposed to water. Investigators working with clays and montmorillonitic rocks have found that expansion is caused by water or ion adsorption onto the electrically charged surfaces of clays. Some investigators postulate that on a molecular scale an "ordering" of the water molecules takes place on the clay, resulting in the water's being "rigid" or "captured". The degree of capture (or the extent of total hydration) is best represented by an adsorption isotherm. When the clay is dry it consists of layers that are close together. Adsorption produces a net flow of water that causes the layers to separate, thus inducing internal expansive stresses. Hydration reduces the clay's strength and density, and alters its electrical resistance. Since shales are essentially quartzitic-feldspathic rocks that contain clay, it was felt that the mechanism just described would be responsible for most of the property alterations that take place when adsorption property alterations that take place when adsorption occurs.

Shales Studied
Samples of 50 shales from formations ranging in depth from 300 to 16,000 ft were collected and studied. All shales were restored to their original state of hydration, and samples of 12 shales were preserved at the wellsite and subsequently tested with minimal exposure to weathering. Control samples deliberately exposed to the atmosphere adsorbed water and eventually fragmented. All samples tested adsorbed fresh water (tap water was used) and evidenced physical alteration. It would be inconvenient to present data on all 50 shales. Instead, results of tests on six shales from as many different locations and depths are presented as being typical. Table 1 shows compositions from X-ray analyses of these shales (designated A through F) and gives their locations and depths. Table 1 also shows the weight percent water of each shale when it is in equilibrium with an atmosphere having a relative humidity of 50 percent. Generally, for shales containing an appreciable amount of clay, the weight percent water observed under these conditions percent water observed under these conditions exceeded 3 percent.
Field Test of Cosurfactant-Enhanced Alkaline Flooding
Authors: Falls A. H. , Thigpen D. R. , Nelson R. C. , Ciaston J. W. , Lawson J. B. , Good P. A. , Uber R. C. , Shahin G. T. 
Published: December 2007

SummaryA test of cosurfactant-enhanced alkaline flooding, without polymer for mobility control, was conducted in a small reservoir in the White Castle field, Louisiana. Although the flood was unstable, the process recovered at least 38% of the waterflood residual oil in the reservoir as true tertiary oil and exhibited virtually 100% displacement efficiency. Alkali and cosurfactant propagated through the reservoir with acceptable and predictable losses.
p-x Behavior of a Rich-Gas Condensate in Admixture With CO2 and (N2 + CO2)
Authors: Chaback J. J. , Williams M. L. 
Published: December 2007

Summary
Pressure/composition (p-x) behavior was studied by use of a rich-gas condensate with CO2 and nominally equimolar (N2+CO2) at two temperatures characteristic of gas-condensate reservoirs, 215 and 316°F. The revaporization of retrograde liquid also was studied at 215°F; CO2 was found to be more effective than (N2+CO2) in revaporizing retrograde liquid.
Wellbore Transmissibility from Afterflow-Dominated Pressure Buildup Data
Authors: McKinley R.M. 
Published: December 2007

Abstract
This paper shows how pressure buildup data distorted by afterflow can beanalyzed directly to give a numerical value for effective wellboretransmissibility. Because such data are directly indicative of wellbore-limitedproductivity, the method is helpful in assessing productivity, the method ishelpful in assessing the need for and the effectiveness of a well stimulation. Alternatively, it is a method for interpreting that portion of a pressurebuildup curve not subject to Horner analysis.
The method does not require any estimates of formation or wellboreproperties for the analysis. The procedure consists of first plotting pressurebuildup from flowing plotting pressure buildup from flowing pressure as afunction of shut-in time on a log-log pressure as a function of shut-in time ona log-log scale and, second, matching the data points to one of a set ofparametric type curves. From this match, a numerical value is calculated forwellbore transmissibility. Finally, the shape of the buildup curve indicateseither wellbore damage or stimulation.
The paper describes the generation and use of type curves with computed dataillustrating the effects of wellbore damage or stimulation. A variety of fieldexamples demonstrate the practical utility of the method. practical utility of the method

Introduction
Afterflow, or afterproduction, is the continued influx of fluid from aformation into a wellbore after the well is shut in. The greater the storagecapacity of the wellbore, the longer the duration of afterflow. Such afterflowprecludes a conventional analysis of a pressure buildup curve so long as theafterflow rate is greater than a few percent of the production rate prior toshut in. Consequently, production rate prior to shut in. Consequently, afterflow has generally been regarded as a nuisance. Yet, it is reasonable tosuppose that such data contains valuable information. Certainly most of thepressure change occurs during afterflow provided it is present; hence, pressuremeasurements during afterflow should pressure measurements during afterflowshould be more accurate than at later times. Also, the pressure change in thewellbore during afterflow should reflect a sort of dynamic balance between twolimiting factors:the capacity of the wellbore to store fluid andtheease with which the formation supplies fluid to the wellbore.
This secondfactor, which is indicative of wellbore transmissibility, is the one oftechnical importance since it determines productivity. However, most of thepublications dealing with afterflow are concerned either with estimating itsduration or with correcting pressure buildup data taken during its pressurebuildup data taken during its duration. Gladfelter, et al. gave a method forcorrecting pressure buildup data as early as 1955. Ramey has provided equationsto estimate the duration of afterflow.
Planning and Analysis of Pulse-Tests
Authors: Brigham W.E. 
Published: December 2007

Developed here are equations that approximate the pulse-test procedure and that, in turn, are plotted as simple graphs that can be used directly to design and analyze these tests. The necessary calculations require only 10 to 15 minutes.

Introduction
Pulse-testing is a fairly recent procedure that has received some attention in the last 2 years. In this method of testing, a well is pulsed with cycles of injection followed by shut-in, or production followed by shut-in. The pressure response to the cycles is then measured in an offset well.
Articles in the literature1,2 discuss, to some extent, the theory of pulse-testing; but an engineer who wishes to analyze the results of such a test will find that he must make a number of tedious exponential integral calculations.
The paper briefly covers the theoretical rationale behind pulse-testing, and then develops some approximate equations. As a result of these equations, two simple graphs are developed that can be used for design and analysis of pulse-tests. An example calculation is shown later in the text.

General Response Theory
Pulse-testing was first discussed by Johnson et al.l The concepts involved are fairly straightforward. Briefly, the bottom-hole pressure in a shut-in well will respond to production or injection cycles in an offset well. The magnitude and timing of the response depend on the flow rate, the permeability, porosity and thickness of the formation, and the compressibility and viscosity of the fluids that lie between the wells. Inhomogeneities, geometry and boundaries also affect the response, but these factors are not included in the scope of this paper, nor in the literature.
The equations for the response are line-source solutions to the diffusivity equation. For instance, if a well is produced for a time ?t, then shut in, the equation for the pressure response in the shut-in well isEquation 1
Going further, if there are a number of cycles of production followed by shut-in, if each production rate is equal, and if each cycle lasts for an equal period of time (?t), then by superposition the equation for the pressure response becomesEquation 2
where N is the number of equal-length periods of production and shut-in (for instance, for one production and one shut-in period, N=2; Eq. 1).
Eq. 2 is the same as cited by Johnson et al. Notice that each shut-in and production period is assumed equal. This is not necessary, but it is easier to handle theoretically and will be used throughout the rest of this paper. Also notice that Eqs. 1 and 2 are for production and shut-in. For continuity we will continue to speak of production; but the reader should realize that injection and shut-in will work equally well. We would merely reverse the signs.
Simultaneous Determination of Basic Geometrical Characteristics of Porous Media
Authors: Perez-Rosales Candelario 
Published: December 2007

Abstract
A statistical method for determining simultaneously some of the basic geometrical characteristics of porous media such as porosity, specific surface, porous media such as porosity, specific surface, mean pore with, mean grain thickness and absolute permeability is presented. The proposed method is permeability is presented. The proposed method is characterized by its simplicity and the minimum amount of laboratory equipment that it requires. The experimental procedure used to evaluate the various geometrical characteristics is based upon the surface analysis of a sample. in view of this fact the applicability of the method is limited to homogeneous and isotropic materials.

Introduction
The behavior of a fluid flowing through a porous medium depends, among other things, upon the internal geometry of the medium; hence the importance of developing efficient methods to determine the geometrical properties of porous materials. This paper describes a statistical method to determine simultaneously some of the basic geometrical properties of porous materials such as porosity, specific surface, mean pore width, mean grain thickness and absolute permeability. The mathematical formulation has been developed that the data required to calculate the various geometrical characteristics of a sample can be easily measured by analyzing a section of the sample with an evenly spaced grid.
Development of an Expert System To Assist With Complex Fluid Design
Authors: Chiu T. J. , Caudell E. A. , Wu F. L. 
Published: December 2007

Summary
The design of fluid systems for well completion has always been a perplexing problem for engineers and chemists. Material incompatibilities, chemical interaction, physical restrictions, and cost considerations build a great deal of complexity into the designs. Many engineers do not have the theoretical background needed to evaluate the numerous available additives. Others may not have the practical experience required to optimize a fluid treatment. Expert systems, with their unique structure and knowledge representation, can be used efficiently as tools to advise engineers of the proper base fluids and additives to be selected for a given set of well conditions. Valuable resources and operation costs can be saved by providing good material recommendations. In addition, use of expert systems can help centralize and retain expertise within the organization. The fundamental elements of expert systems—namely, the knowledge base, inference engine, and user interface—are addressed in this paper, along with knowledge acquisition and system implementation. Acid Expert, an expert system designed for matrix-acidizing-treatment recommendation that has been released to locations worldwide, is used as an example for much of the discussion.
Multifluid Acid-Fracturing Design Program
Authors: Bartko K. M. , Bender J. P. 
Published: December 2007

Summary
A multifluid acid-fracturing design program, ACIDFRAC, was developed for IBM PC and Apple Macintosh computers to assist in the design of acid-fracture stimulations. The simulator compares the results of closed-fracture acidization and conventional acid-fracture stimulation. The program was designed for ease of use, incorporating data input windows, on-line help panels, and user-input checks for validity. The user moves through the program with a navigator window. Data validity is checked by a status window. The program has the ability to handle multiple rates, 15 stages, and up to five different fluid systems, correctly handling the fluid properties of each system. The fracture geometry is obtained from a 2D fracture simulator using a Perkins-Kern-Nordgren1, 2 model. The acid-transport model uses an infinite reaction rate and an empirical correlation to partially account for finite reaction rates. Data is output through multiple resizable graphs with zoom and expand capabilities. A complete report can be displayed or printed, including input and digital output data.
CHES: Casing Hydraulic Expert System
Authors: Heinze L. R. 
Published: December 2007

Summary
An operations-oriented, practical application of expert-systems technology to tubular design and to optimizing bit hydraulics, Casing Hydraulic Expert System (CHES), was developed. Drilling operations are the most costly expenditure in exploiting hydrocarbon fossil fuels. The reduction of drilling cost is more important today than ever before in the oil industry.
An Expert System for Miscible Gasflooding
Authors: Khan Sameer. A. , Pope Gary A. , Sepehrnoori Kamy 
Published: December 2007

Summary
A user-friendly prototype expert system (UTINPUT) was developed for preparing input data sets to design miscible gasfloods with the U. of Texas Compositional Simulator (UTCOMP). The expertise we acquired through literature, simulation experts, and simulation studies was implemented in an expert-system shell with rules, objects, and C.
GEOLITH: An Interactive Geostatistical Modeling Application
Authors: Araktingi U. G. , Hewett T. A. , Tran T. T. B. 
Published: December 2007

Summary
A menu-driven workstation application program designed to analyze reservoir data and construct reservoir simulation models with a geostatistical approach is presented. The program analyzes reservoir data in the form of well logs and interpreted bed markers and allows interactive fitting of variogram models to data. These models then are used to construct gridded models of reservoir flow properties by kriging and conditional simulations and the use of flow-property transforms of well log values. The interpolation of data to the interwell region is done in a stratigraphic framework that honors the geologic interpretations provided by the bed markers. Small-scale variations are added through a number of methods (matrix, fractal, sequential, simulated annealing) to produce conditional simulations that reproduce the measured variability of properties at unsampled locations. The program also integrates indirect information, such as acoustic impedance derived from seismic data, with well-log data by several different methods.
The program has an intuitive and accessible data interface, a structured sequence of user prompts and error checks, and striking graphical presentations of modeling results. With it, the complex task of converting geological data into quantitative reservoir models for flow simulation and reservoir performance prediction is greatly streamlined.
Electronic Publishing of SPE Papers
Authors: Perdue Jeanne M. , Perkins John. L. 
Published: December 2007

Summary
The SPE is creating an electronic index to more than 24, 000 technical papers and will produce a compact disk-read only memory (CD-ROM) as an initial product. This SPE CD-ROM Masterdisc will be available at the 1992 SPE Annual Technical Conference and Exhibition in Washington, DC, Oct. 4-7. The SPE Board has apppointed an Ad Hoc Committee on Electronic Publishing to coordinate and oversee this project and to recommend standards for submitting SPE papers electronically in the future.