bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Applications of Scanning Electron Microscopy to the Study of Reservoir Rock
Authors: Pittman E.D. , Thomas J.B. 
Published: December 2007

The scanning electron microscope (SEM) provides qualitative information about pore geometry through direct observation of a rock or a pore cast of the rock. This aids in understanding reservoir productivity capabilities. The SEM is useful for locating and identifying minerals, particularly clay minerals -an aid when designing drilling and completion programs.

Introduction
This paper discusses some applications of the scanning electron microscope (SEM) to the study of reservoir rocks. The SEM is used extensively to provide qualitative information about the pore geometry of rocks, either directly or indirectly through the examination of pore casts. Many of these studies were concerned with relating pore geometry to various tests or rock properties; specific applications also are discussed.The basic principles of the SEM were known in 1935. Experimental instruments were built in Germany and the U.S. before World War II. After the war, the British started a research program that eventually developed a commercial instrument in the early 1960's. Since then, the SEM has become an indispensible scientific tool in all fields of science and industry. Presently, there are approximately 10 SEM manufacturers, with prices ranging from about $17,000 to well over $ 100,000.The SEM provides several unique advantages for the geologist or engineer when compared with other types of microscopes:magnification range of 15 x to a practical upper limit of about 40,000 x for rocks,great depth of field,ease of sample preparation - samples made conductive by a coating of metal applied under vacuum,nondestructive sample study, andthree-dimensional image analogous to reflected light requiring no special techniques for interpretation.
These features make the SEM ideal for studying irregular rock surfaces.An energy-dispersive X-ray attachment for the SEM provides qualitative information on chemical elements and aids in identifying minerals.

Evaluation and Importance of Microporosity
Micropores occur in sandstone and carbonate reservoirs and affect fluid flow properties. These micropores are seen and evaluated best with an SEM. Microporosity, for convenience, has been defined as pore apertures with a radius of less than 0.5 mum.In sandstone reservoirs, clay with associated micropores may occur as detrital laminae, pellets (grains) of silt-sized or coarser material, or as authigenic (that is, newly formed or regenerated) material (Fig. 1). In a water-wet sandstone, the micropores and high surface area associated with the clay minerals are conducive to holding significant amounts of bound water that can affect log calculations for water saturation. Because of improved log-calculation techniques, which take into consideration cation-exchange capacities of clay minerals, this is less of a problem than in the past.Micropores in carbonate reservoirs occur among calcite or dolomite crystals that typically are less than 4 mu m in diameter.
JPT
P. 1375＾
Packer-to-Tubing Forces for Intermediate Packers
Authors: Hammerlindl D.J. 
Published: December 2007

Changes in temperature and pressure during pump-in and production usually result in changes in tubing length or tubing and packer forces, depending on whether the tubing is free to move. Earlier papers presented means for calculating these effects for a completion containing one packer. This paper briefly summarizes those papers and generalize, the calculation to paper briefly summarizes those papers and generalize, the calculation to completions with more than one packer.

Introduction
This paper presents a means of calculating the forces that occur at intermediate packers as a result of changes in temperature and pressure. Intermediate packers are those within the tubing string, such as packers are those within the tubing string, such as dual packers or selective completion packers. The intermediate packer-to-tubing force is needed to design multi- and selective-well completions so that the well can be treated through the completion assembly. Without a proper design, it is possible to shear the release mechanism in the intermediate packer(s), which can result in a costly failure of the packer(s), which can result in a costly failure of the completion assembly.This paper is an extension of papers by Lubinski et al. and Hammerlindl. To eliminate much cross-referencing, the basic equations of Refs. 1 and 2 are presented with a brief review of the theory. presented with a brief review of the theory. This paper also develops the theory required to solve intermediate packer-to-tubing forces, illustrates solutions to typical problems, and develops the initial packer-to-tubing forces that result when the packer-to-tubing forces that result when the intermediate packer is set hydraulically.The calculation procedure requires working the problem from the lowest packer to the surface in problem from the lowest packer to the surface in stages. The first stage is the tubing between the first and second packers; the second stage is the tubing between the second and third packers (or the surface if there is no third packer), etc. The procedures are the standard ones used in Refs. 1 and 2. The only changes are in the procedures used to determine the actual and fictitious forces and the changes in length due to applied forces at the intermediate packers.The text pertains to uniform completions unless otherwise stated. A uniform completion is one with a single-size tubing string containing only one fluid and a constant-ID casing string where the annulus contains only one fluid, which may or may not be the same fluid as contained in the tubing.

Compendium of Movement and Forces Applied Forces With No Fluid
If a tubing string is suspended freely in a cased well containing no fluid and a tensile force is applied to the lower end in the axial direction, the tubing elongates. If a compressive force is applied, the tubing shortens and buckles.The elongation due to a tensile force is determined from Hooke's law. The e nation for Hooke's law in terms of length change is(1)
JPT
P. 515
Factors Affecting Water Blocking and Gas Flow From Hydraulically Fractured Gas Wells
Authors: Holditch Stephen A. 
Published: December 2007

This paper demonstrates the combined effects of formation permeability damage and relative permeability damage in the invaded zone of a hydraulically fractured gas well. Study results indicate that the damaged zone permeability must be reduced by several orders of magnitude and the capillary pressure altered before a serious water block to gas flow will occur.

Introduction
To optimize profit from low-permeability gas reservoirs, well stimulation normally is required. In a majority of the cases, a long hydraulic fracture will provide the most efficient and economic means of stimulation. To create long hydraulic fractures, a large volume of fluid, mixed with additives and granular propping agents, must be pumped into the formation. Such treatments can be expensive and require extensive engineering effort.
The fluid injected during the fracturing treatment will leak off into the formation and will reduce the relative permeability to gas in the invaded region. Near the fracture, the permeability to gas will be reduced to zero. After injection has ceased, imbibition will begin to alter the fluid distribution, and when production begins, the fracturing fluid will flow from the formation into the fracture. As the fracturing fluid is produced, the relative permeability to gas in the invaded zone will increase and gas will begin to flow into the fracture. In some cases, the injected fracturing fluid may reduce the formation permeability in the invaded zone. Such damage can be caused by clay swelling, precipitation of solids, or migration of released fines.
In reality, all fracturing fluids, no matter how expensive, do some damage to the reservoir adjacent to the fracture. Using clean fracturing fluids that are compatible with the formation rock and the reservoir fluid helps minimize such damage. However, in some reservoirs, the injected fracturing fluid does not readily clean up and several months of production may be required before the maximum gas flow rate is achieved. In the most extreme cases, a complete water block to gas flow can occur.
To effectively design a fracture treatment for a water-sensitive reservoir, it is essential to understand the basic reservoir mechanisms that govern flow between the fracture and the formation. Gas and water relative permeability, relative permeability hysteresis, capillary pressure, and reservoir damage all tend to complicate the analysis of reservoir flow in fractured formations. By considering the combined effects of the above parameters, it is possible to analyze a given reservoir and determine the cause of slow cleanup and reduced gas productivity.
Tall Oil Pitch in Chemical Recovery
Authors: Ying-Chech Chiu 
Published: December 2007

Abstract
This paper describes a laboratory investigation of tall oil pitch as a potential alternative to petroleum sulfonate as a surfactant for chemical recovery. Tall oil pitch is a bottom product of tall oil fractionation that is based on a major by-product of the paper industry. It is inexpensive, substantially available, and derived from a renewable resource. It is a complex solid consisting of fatty acids, rosin acids, and unsaponifiables. Oil recovery in Berea sandstone cores has shown that final residual oil can be lowered to several percent by injecting properly formulated tall oil pitch solutions in high-salinity field water at 158 and 195°F (70 and 90°C).
Tall oil pitch must be neutralized to achieve interfacial activity. Usual neutralization of tall oil pitch with sufficient alkali to balance the acid equivalence results in surfactant solutions unfavorable for chemical flooding. Alternative neutralization methods are shown to produce solutions that give better oil recovery and no plugging problem in core experiments.
Tall oil pitch has low salinity tolerance, and the additionof NEODOL® 25-3S does not provide satisfactory interfacial activity, salinity tolerance, and temperature stability. Alternative methods of increasing field water compatibility of tall oil pitch slugs have been investigated. Good oil recovery has been obtained with slugs containing as much as 26,280 ppm total dissolved solid.
Five different sources of tall oil pitch were studied. Oil recovery efficiency was shown to be parallel with the fatty-acid dimer content of the sample as determined by gel permeation chromatograph. Heat treatment of the pitch to increase the fatty-acid dimer content improves recovery performance. This finding is important not only in controlling the activity of tall oil pitch but also in providing new leads to what makes certain surfactant materials active.
Henry Darcy - Engineer and Benefactor of Mankind
Authors: Fancher George 
Published: December 2007

Introduction
The petroleum industry, and particularly that part of it that is concerned with the production of oil and natural gas, depends upon the ability of these fluids to flow through the porous rocks of the subterranean reservoirs in which they are imprisoned. The ability of fluids to flow through porous rock is expressed in the language of mathematics by Darcy's law, and this mathematical statement is the basis of many petroleum engineering computations. Petroleum engineers have found it the most useful, fruitful, and dependable expression of the pertinent factors which govern the ability of reservoirs to produce oil, gas, and water and of wells to yield these fluids. Consequently, it is not too much to say that Darcy's law is the very basis of the modern petroleum industry.
Darcy's law was stated and published just 100 years ago, when Henri Philibert Gaspard Darcy published his classic paper on the flow of water through sand filter beds. It is fitting that this important anniversary be commemorated by the petroleum industry, although no one would be more surprised than Henry Darcy himself that the work to which he devoted his comparatively brief professional career should provide the basis for a gigantic industry which is the bulwark of modern civilization, an industry which began just three years after the first published statement of Darcy's law. Although petroleum engineers make use of Darcy's law daily in the preparation of professional analyses and reports, and executives of the oil industry, bankers and business men, public officials, politicians, and heads of state arrive at decisions on the basis of these analyses and reports the details of the life and work of this humble Frenchman and public servant, Henry Darcy, are known to few.

Early Life of Darcy
Henri Philibert Gaspard Darcy was born June 10, 1803, in the city of Dijon, chief town in the Department of Cote d'Or and former capital of the old Duchy of Burgundy. Dijon is situated at the confluence of the rivers Ouche and Saone, some 210 miles southeast of Paris by rail (about 160 miles by air line). It is a city of order and discipline, a city of old forts, palaces, bridges, public buildings and worksfactors no doubt of some importance in shaping and molding the lives of its citizens. Deprived at 14 of his father, who was Collector of the Registry and well thought of by his superiors and fellow citizens, Henry Darcy was reared by his mother, a woman of rare merit who, although left a widow at an early age, devoted her energy to the rearing of her two sons and who was responsible for their education.
Rate Effects in Tertiary Micellar Flooding of Bradford Crude Oil
Authors: Sayyouh M. H. M. , Ali S. M. Farouq , Stahl C. D. 
Published: December 2007

Abstract
Micellar flooding of the tight Pennsylvania oil reservoirs invariably is accompanied by low flood advance rates – on the order of a fraction of 1 ft/D. This investigation, therefore, was devoted to the effect of rate on tertiary oil recovery.
The experiments were conducted in 2- and 4-ft-long Berea sandstone cores at rates as low as 0.10 ft/D. All runs were tertiary in nature. The micellar solutions being used in the field tests in Pennsylvania also were used for this research. The majority of the runs were carried out in horizontally positioned cores (although a few runs used vertical cores) to determine if gravity was a factor in the observed effect.
It was found that oil recovery decreased with a decrease in the flood advance rate up to a point. Thereafter, it showed a small increase with further decrease in rate. This effect has not been reported by other investigators.
The rate effect is discussed and analyzed in terms of the system phase behavior, sulfonate adsorption, dispersion, diffusion, and mobility control. The role of the rate effect on the formation of the stabilized bank also was developed for the experimental conditions involved. The implications of very low rates are discussed in the light of field results.
The Reciprocity Principle in Fluid Flow Through Porous Media
Authors: Falade G.K. , Brigham W.E. 
Published: December 2007

Abstract
The mathematical definition of the reciprocity principle is developed using the concept of the instantaneous Green's function. Investigation of the validity of the principle is extended to cases where pressure-sensitive principle is extended to cases where pressure-sensitive parameters of skin and storage are present at the parameters of skin and storage are present at the wellbores of the test wells. Generally, the reciprocity principle is not valid for wells with skin and storage principle is not valid for wells with skin and storage factors. However, for special cases where these pressure-sensitive parameters fulfill certain carefully laid out pressure-sensitive parameters fulfill certain carefully laid out conditions for the well pair of interest, the principle is perfectly valid. perfectly valid.

Introduction
The reciprocal relationship between two wells within a domain in a porous medium probably was reported first by McKinley et al. A similar observation also was reported by Bruggeman for hydrological systems. Also, recently Falade, in his study of pulse testing in slab reservoirs, reported the reciprocity behavior with the pulsing and responding well pair. pulsing and responding well pair. The reciprocity principle as applied to fluid flow through a porous medium can be stated as follows: the pressure change at an Observation Well A, due to a pressure change at an Observation Well A, due to a stimulus of Strength Q imposed on a Source Well B is identically equal to the pressure change at Well B if Well A were subjected to a stimulus of equal Strength Q for an equal length of time. Thus, in effect, the source well and the observation well can be interchanged readily with essentially the same result.Extension and applications of this generalized theory to well testing in a multiwell field and its intrinsic advantages are obvious. Valuable operational costs involved in a complete well-to-well testing of a field can be reduced significantly by applying the reciprocity principle. This paper tries to explore more in-depth principle. This paper tries to explore more in-depth implications of the reciprocity principle as it affects routine oilwell testing.

Theoretical Development
The mathematical proof of the reciprocity principle can be formulated on a general basis using the concept of instantaneous Green's function. Green's function as applied to the solution of a diffusivity equation recently was highlighted by Gringarten et al. and can be extended easily from the single-well case to that of a multiwell field situation.The generalized pressure response at Point R in an infinite porous medium described as a two-well (or two-domain system) is given as
(1)
If the boundary conditions given at the wellbores are the Neuman type as is usually the case (prescribed flow rate), the normal derivatives of the Green's function will vanish at these boundaries:
(2)
SPEJ
P. 200
The Reliability of Core Data as Input to Seismic Reservoir Monitoring Studies
Authors: Nes O. -M. , Holt R. M. , Fjær E. 
Published: December 2007

Summary
There is a potential for improving the reliability of standard core tests for seismic monitoring studies. A primary concern is the ability to quantify and correct for core-damage effects, which significantly enhance the stress dependency of wave velocities. This problem is most relevant for relatively low-strength rocks cored in high-stress environments. We have used synthetic sandstones formed under stress to perform a systematic study of stress-release-induced core-damage effects. The results show that careful laboratory procedures and modeling efforts may reduce core damage effects. However, no simple procedure is currently available to eliminate the problem. The use of simplified laboratory test procedures, particularly the application of an inappropriate effective stress principle, may lead to erroneous interpretations.
The Operator Compact Implicit Method for Reservoir Simulation
Authors: Leventhal Stephen H. 
Published: December 2007

Abstract
This paper describes the application of the fourth-order operator compact implicit (OCI) method to multiphase flow through porous media. A conservative form of the method is developed and used to solve a one-dimensional, two-phase, immiscible waterflood problem.
The results of numerical experiments demonstrate the ability to track sharp fronts with relatively few mesh points. Comparisons with conventional finite-difference methods and variational methods are given.
Field Investigation of the Effects of Stick-Slip, Lateral, and Whirl Vibrations on Roller-Cone Bit Performance
Authors: Chen S. L. , Blackwood K. , Lamine E. 
Published: December 2007

SummaryThe effects of downhole vibrations on the performance of poly-crystalline diamond compact (PDC) bits have been well discussed in recent years. However, most studies on the downhole dynamics of roller-cone bits have focused on axial vibration and its effects. The questions that remain to be answered are what kinds of vibrations a roller-cone bit experiences and what the effects of these vibrations are on roller-cone bit performance.To investigate these questions, a series of laboratory and field tests was conducted. Downhole vibration data were recorded by an advanced instrumented sub. Soft-to medium-hard formations were drilled with four 8½-in. roller-cone bits (IADC 517). Three kinds of harmful vibrations were observed, and their effects on bit performance in terms of rate of penetration, insert breakage, and bearing/seal life are discussed.
Richardson's Iteration With Dynamic Parameters and the SIP Incomplete Factorization for the Solution of Linear Systems of Equations
Authors: Saylor Paul E. 
Published: December 2007

Abstract
Reservoir simulation yields a system of linear algebraic equations, Ap = q, that may be solved by Richardson's iterative method, p(k+1)= p(k)+ tkr(k), where r(k)= q − Ap(k) is the residual and t0, … tk are acceleration parameters. The incomplete factorization, Kα, of the strongly implicit procedure (SIP) yields an improvement of Richardson's method, p(k+1)=p(k)+tkKα−1r(k). Parameter α originates from SIP. The product of the L and U factors produced by SIP gives Kα = LU. The best values of the tk acceleration parameters may be computed dynamically by an efficient algorithm; the best value of α must be found by trial and error, which is not hard for only one value. The advantages of the method are (1) it always converges, (2) with the exception of the α parameter, parameters are computed dynamically, and (3) convergence is efficient for test problems characterized by heterogeneities and transmissibilities varying over 10 orders of magnitude. The test problems originate from field data and were suggested by industry personnel as particularly difficult. Dynamic computation of parameters is also a feature of the conjugate gradient method, but the iteration described here does not require A to be symmetric. Matrix Kα−1 must be such that the real part of each eigenvalue is nonnegative, or the real part of each is nonpositive, but not both positive and negative. It is in this sense that the method always converges. This condition is satisfied by many simulator-generated matrices. The method also may be applied to matrices arising from the simulation of other processes, such as chemical flooding.
A Numerical Model Coupling Reservoir and Horizontal Well-Flow Dynamics: Transient Behavior of Single-Phase Liquid and Gas Flow
Authors: Vicente Ronaldo , Sarica Cem , Ertekin Turgay 
Published: December 2007

SummaryA fully implicit, 3D simulator with local refinement around the wellbore is developed to solve reservoir and horizontal well flow equations simultaneously for single-phase liquid and gas cases. The model consists of conservation of mass and Darcy's law in the reservoir, and mass and momentum conservation in the wellbore for isothermal conditions. The coupling requirements are satisfied by preserving the continuity of pressure and mass balance at the sandface. The proposed simulator is tested against and verified with the results obtained from a commercial code ECLIPSE-100, and available public domain simulators and semianalytical models.The model can be used to simulate the transient pressure and flow rate behavior of both the reservoir and the horizontal wellbore. Traditional decoupling of the wellbore transients from the reservoir transients does not capture the horizontal well pressure and flow rate transients at early times because the interaction between the reservoir and wellbore is inherently neglected. Simulation runs with the proposed model reveal the actual characteristics of horizontal wellbore storage and unloading, as well as flow pattern determination during transient well testing using pressure derivative curves. The effects of permeability, formation thickness, well length, and fluid compressibility are also studied.