bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scale Deposition in Surface and Subsurface Production Equipment in the Gulf of Suez
Authors: El-Hattab M.I. 
Published: December 2007

Abstract
Generally the deposition of oilfield scale in surface and subsurface production equipment can cause many operational problems. Scale precipitation in oilfields has a detrimental effect on fluids, processing equipment, pipelines, and downhole well equipment processing equipment, pipelines, and downhole well equipment as a result of Corrosion and flow restriction. Scale deposits in wellbores can result in severe production loss. Generally scale problems become more prevalent as oil and gas reserves are depleted and water production increases. production increases. Some of the Gulf of Suez oilfields, El Morgan, July, and Ramadan, have been waterflooded by the Gulf of Suez sea water. Compatibility tests have indicated probable deposition of scale on surface and probable deposition of scale on surface and subsurface production equipment. Case histories relating to scale deposition, removal and inhibition in surface equipment are discussed. The paper outlines the physical and theoretical prediction for downhole physical and theoretical prediction for downhole scale deposition in oil wells. The experience with scale removal and inhibition by the formation squeeze treatment technique is presented along with recommendations that can be applied to similar cases in other fields in the Gulf of Suez.

Introduction
The deposition of oilfield scale in surface and subsurface oil and gas production equipment has been recognized to be a major operational problem. The negative consequences of scale contribute to equipment wear and corrosion and flow restriction thus resulting in production decrease. Experience in the oil industry has indicated that many wells have suffered flow restrictions due to scale deposition within the formation, the well bore region, perforations, and tubing strings. Scale deposits in surface production equipment amplify these problems.
Oilfield scale costs much in terms of production losses, frequent pulling jobs, reperforations, redrilling and reaming, stimulation, and other similar remedial workovers. It is estimated that many wells in the U.S.A. have reduced production due to scale deposits in the formation and wellbore and that many oil producers and formations have been prematurely abandoned due to plugging by scale deposits. prematurely abandoned due to plugging by scale deposits. In the literature many case histories regarding the oilfield scale problem have been reported. Cowan et al have stated cases for calcium carbonate scale deposition in surface production equipment, in Mexico, South and West Texas, and North and South Louisiana oilfields.
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Stability of Displacement Fronts in Porous Media—Growth of Large Elliptical Fingers
Authors: Mui Kwoon C. , Miller Clarence A. 
Published: December 2007

Abstract
A theoretical analysis is presented for growth of a single, large elliptical finger in a porous medium. The objective is to obtain an understanding of how large fingers develop once a displacement front has become unstable. The results provide information beyond that available from linear analysis, which has been used in most previous work and applies only to infinitesimal perturbations.
Separate analyses are given for finger growth during instability of (1) the front accompanying displacement of one immiscible fluid by another, (2) the combustion front in a dry, forward combustion process, (3) a condensation front, and (4) the combustion front in dry, reverse combustion as employed in the linking step of underground coal gasification. In Cases 1 and 2, the fastest-growing finger is found so that growth rate and finger size can be estimated. In contrast, the linear analyses for these cases predict no fastest-growing disturbance. Thus, important additional information is provided by the elliptical finger model.
In Case 3, the condensation front, a fastest-growing disturbance is found as well. Results show that effects on stability of the mobility ratio and of the volume decrease accompanying condensation depend only on the shape of the finger (ratio of major and minor axes) while heat transfer effects also depend on the absolute size of the finger. Since the stabilizing effect of heat transfer is least for large fingers, such fingers are favored.
For Case 4, we found that the channel in underground coal gasification always advances at the maximum speed permitted by the reaction kinetics. Actual results confirm the basic validity of those obtained by Gunn and Krantz using linear analysis, but the elliptical finger model provides a clearer understanding of the physical phenomena controlling finger size and speed.
Wind Tunnel Tests of Inclined Circular Cylinders
Authors: Norton David J. , Heideman John C. , Mallard W. Wade 
Published: December 2007

Abstract
Forces on naturally roughened cylinders were measured for Reynolds numbers between 2×105 and 2×106 and inclinations of 0 to 40°. Results demonstrated the validity of the flow-independence principle in postcritical flow. Drag coefficients agreed with published values for artificially roughened cylinders. Strouhal numbers of about 0.21 were observed.
Approximate Solutions for Fractured Wells Producing Layered Reservoirs
Authors: Bennett Curtis O. , Camacho-V. Rodolfo G. , Reynolds A. C. , Raghavan Rajagopal 
Published: December 2007

Abstract
New analytical solutions for the response at a well intercepting a layered reservoir are derived. The well is assumed to produce at a constant rate or a constant pressure. We examine reservoir systems without in-terlayer communication and document the usefulness of these solutions, which enable us to obtain increased physical understanding of the performance of fractured wells in layered reservoirs. The influence of vertical variations in fracture conductivity is also considered. Example applications of the approximations derived here are also presented.
Fluid Flow in Cracks as Related to Low-Permeability Gas Sands
Authors: Brower K. R. , Morrow N. R. 
Published: December 2007

Abstract
A problem in formation evaluation of tight gas sands is that their permeabilities are sometimes surprisingly sensitive to variations in overburden pressure. Photomicrographs of pore casts show an interconnected system of sheet pores, which are somewhat like the surfaces of a randomized honeycomb. A mathematical relation for predicting the pressure dependence of flow rate in sheet pores has been derived from the dimensions of the pores and the elastic constants of the matrix. The equation has been validated by measurements on artificial media containing cracks of known dimensions in glass and concrete. The observed pressure sensitivity of the gas sands used in this study requires the aspect ratio of the pores (in this case, the ratio of average large dimensions to sheet thickness) to be greater than 100. Aspect ratios have been determined by taking the large dimension from photomicrographs of pore casts or grain size and the thickness from mercury injection pressure or the slope of a plot of apparent permeability vs. the reciprocal of mean gas pressure. The latter gives the diffusive contribution to gas flow from which the pore size can be calculated. The two methods for measuring pore size give satisfactory agreement. The aspect ratios for the sheet pores in tight gas sands are large enough to explain the dependence of permeability on overburden pressure.
Measurement of Width and Pressure in a Propagating Hydraulic Fracture
Authors: Warpinski N. R. 
Published: December 2007

AbstractMeasurements of width and pressure in a propagating hydraulic fracture have been made in tests conducted at the U.S. DOE's Nevada test site. This was accomplished by creating an "instrumented fracture" at a tunnel complex (at a depth of 1,400 ft [425 m]) where realistic in-situ conditions prevail, particularly with respect to stress and geologic features such as natural fractures and material anisotropy.Analyses of these data show that the pressure drop along the fracture length is much larger than predicted by viscous theory, which currently is used in models. This apparently is caused by the tortuosity of the fracture path, multiple fracture strands, roughness, and sharp turns (corners) in the flow path resulting from natural fractures and rock property variations. It suggests that fracture design models need to be updated to include a more realistic friction factor so that fracture lengths are not overestimated.
The Selection of a Multiple Completion Hook-Up
Authors: Althouse W.S. , Fisher H.H. 
Published: December 2007

Abstract
The reasoning behind the inception, rate of development and successful application of current dual, triple and quadruple completions is highly economic in character. Selection of a practical multiple completion hook-up therefore must necessarily involve strong economic considerations. Type and subsequent cost of any multiple completion hook-up is directly related to number of zones to be produced and workover and artificial-lift requirements of each zone. An analysis of available subsurface equipment that makes the modern multiple completion practical in the light of design, advantages and limitations provides a base for selection of components. A systematic presentation of multiple completion hook-ups from the simplest, most inexpensive two-zone completion to the most complex four-zone completion, in order of increasing cost and flexibility provides a graphic systematic base for selection of a practical multiple completion hook-up.

Introduction
Advancement in multiple zone techniques and equipment has been so rapid in recent years that it becomes difficult even for those who specialize in this field not only to keep up with it, but to maintain an over-all perspective. Hardly a month goes by that a trade publication does not present a new dual, triple or quadruple completion method. Many of these articles not only imply widespread acceptance of the particular method but strongly suggest that previous methods are shortly doomed for obsolescence. The facts are that there are many areas, perhaps an overwhelming majority, where the complex dual, triple or quadruple completion would not be economically feasible.
Operators in these areas are confronted with the problem of selecting not only a practical multiple completion hook-up but one that is economical as well. In order to make this selection they should have as broad a view of all multiple completion techniques and equipment as possible and some sort of systematic method of evaluating each method in light of any given set of conditions. The systematic basis for this selection in our opinion involves(1) number of zones to be produced; (2) flowing, artificial-lift and workover requirements of each zone; (3) general knowledge of various types of subsurface equipment and its limitations; and (4)general knowledge of possible remedial operations that can be performed with certain fundamental hook-ups.
A General Purpose Thermal Model
Authors: Rubin Barry , Buchanan W. Lloyd 
Published: December 2007

Abstract
This paper describes a fully implicit four-phase (oil, water, gas, solid fuel) numerical reservoir model for simulating hot water injection, steam injection, dry combustion, and wet combustion in one, two, or three dimensions and in either a Cartesian, radial, or curvilinear geometry. The simulator rigorously models fluid flow, heat transfer (convective and conductive), heat loss to formation, fluid vaporization/condensation, and chemical reactions. Any number of oil or gas phase components may be specified, along with any number of solid phase components (fuel and catalysts).
The simulator employs either D4 Gaussian elimination or powerful incomplete factorization methods to solve the often poorly conditioned matrix problems. An implicit well model is coupled to the simulator, where reservoir unknowns and well block pressures are primary variables.
This paper includes (1) comparisons of the numerical model's results with previously reported laboratory physical models' results for steam and combustion and (2) analytical solutions to a hot waterflood problem. In addition, an actual field-scale history match is presented for a single-well steam stimulation problem.
Influence of Interfacial Tension on Gas/Oil Relative Permeability in a Gas-Condensate System
Authors: Asar Hamza , Handy Lyman L. 
Published: December 2007

SummaryTo understand better the effect of interfacial tensions (IFT's) on gas/oil relative permeabilities, with particular emphasis on those effective in condensate reservoirs, an experimental procedure was developed and used with the highly volatile methane/propane system. The objective was to measure steady-state relative permeabilities as functions of IFT. Thus the IFT was varied from 0.03 to 0.82 dynes/cm [0.03 to 0.82 mN/m], corresponding to pressures near the critical at a constant temperature of 70°F [21°C].Individual relative permeability curves obtained as a function of gas saturation approach the 45° [0.79-rad] diagonals for both gas and oil as the IFT is lowered. This supports the expectation that relative permeability curves for both gas and oil become straight lines as the IFT approaches zero. At the highest IFT for which experiments were performed (0.82 dynes/cm [0.82 mN/m]), the relative permeability curves approached those obtained for a nitrogen/kerosene flood for which the IFT is approximately 30 dynes/cm [30 mN/m].The most important conclusions derived from this work are that (1) the curvatures of the relative permeability curves diminish as the IFT is reduced, (2) the irreducible gas and liquid saturations approach zero as the IFT approaches zero, and (3) relative gas/oil permeabilities for gas-condensate reservoirs are altered from the normal relative permeabilities only at pressures, temperatures, and compositions close to the critical point.
Ethoxylated Oleyl Sulfonates as Model Compounds for Enhanced Oil Recovery
Authors: Carmona Irene , Schechter R. S. , Wade W. H. , Weerasooriya Upali 
Published: December 2007

Abstract
Precisely ethoxylated oleyl sulfonates were prepared and studied as model surfactant candidates for EOR. They were found to yield low interfacial tensions (IFT's), to give high solubilization parameters, and to have high electrolyte tolerance. Unfortunately, as a class of compounds they have a tendency to form liquid crystals (rather than microemulsions), which must be overcome by adding cosolvents, elevating temperatures, or restricting the maximally ethoxylated species.
Direct Thickeners for Mobility Control of CO2 Floods
Authors: Heller J. P. , Dandge D. K. , Card R. J. , Donaruma L. G. 
Published: December 2007

AbstractThis paper describes efforts in an experimental search for polymers that are sufficiently soluble in dense CO2 that they could serve as mobility control agents. The operation of the apparatus designed and built for the measurement of solubility in condensed gases is described. A modified version of this apparatus has been used to measure viscosity by timing the fall of a cylinder in a tube.More than a dozen polymers have been found that are soluble at least in the parts-per-thousand (ppt) range in liquid and in dense supercritical CO2. As pressures and temperatures are varied, the solubilities of these polymers generally are found to increase with increasing CO2 density. Certain generalizations have been made concerning the influence of various polymer properties on their solubility in dense CO2. These properties include structure, stereochemistry, and molecular weight. Although the viscosity enhancements of the solutions measured thus far are insufficient for purposes of mobility control, they provide clues that point toward those features of polymer molecules that yield greater thickening properties.Also discussed are considerations involved in the application of direct thickeners in the mobility control of CO2 floods and the advantages in the use of such CO2-soluble polymers in place of methods that involve the injection of water.
Pressure Inversion and Material Balance Calculations
Authors: Mead Homer N. 
Published: December 2007

Abstract
In a reservoir when gas comes out of solution and rises, additional pressure is created because of the change in position of this gas in the bounded volume. If this pressure effect is not taken into account as a pseudo-influx in material balance calculations on reservoirs in which there is evolving gas, an error is introduced that is directly proportional to the length of oil column and amount of gas evolved and inversely proportional to the reservoir pressure. In reservoirs with small oil column this pseudo-influx is of little importance. The larger the oil column the more important the effect becomes. The most important application, however, will be for reservoirs with declining pressure in which increasing water entry has been indicated by material balance calculations. It could be that this indication is the result of the cited pseudo-influx and not water entry at all. This paper attempts to explain this phenomenon in relation to material balance calculations and presents an approximate method of determining the pseudo-influx.

Introduction
Only recently has the pressure-volume relationship of gas rising in a liquid appeared in engineering literature, although its effect has been discussed for several years-especially among engineers engaged in drilling operations. The writer published a paper in 1957 in which this phenomenon was examined in relation to blowouts in drilling wells. Also, in 1957 Stegemeier and Matthews authored a paper in which the relationship was presented with respect to pressure build-up tests when shutting in producing wells. In this paper the effect will be called "pressure inversion" which is descriptive of the phenomenon.
Fundamentally, the effect just mentioned is the result of changing the position of a quantity of energy contained within the gas itself (as a result of its compression) within the bounded volume in which the gas exists. If the gas were allowed to expand "beyond all bounds" there could be no pressure inversion effect. This is because all of the energy contained within the gas as a result of compression would have been released.
Bonded Half-Planes Containing Two Arbitrarily Oriented Cracks: A Study of Containment of Hydraulically Induced Fractures
Authors: Lu Chien-Ke , Yew Ching H. 
Published: December 2007

Abstract
In the first part of this paper, the title subject is studied by introducing two modified singular integrals. The problem is reduced to a set of singular integral equations; and it is solved numerically by employing the Lobatto-Chebyshev method. The stress intensity factor at the fracture tips of a hydraulically induced fracture in a layered medium is calculated in the second part of the paper. The effect of the fluid pressure and the in-situ stress gradient as well as the effect of the relative layer material properties on the magnitude of the stress intensity factors are studied numerically. It has been shown that the relative magnitude of the stress intensity factor at the fracture tips can be used to indicate the direction of fracture movement.
Steam Zone Growth in Cylindrical Channels
Authors: Closmann Philip J. 
Published: December 2007

Abstract
The rapid breakthrough of steam that sometimes occurs in steam injection projects has been treated as a case of steam flow through a channel of high permeability. With the assumption of a cylindrical cross-section and steam zone growth limited by heat losses normal to the channel wall and sensible heat requirements within the zone, it is possible to estimate the channel size from the time of steam breakthrough at a producer.
Fully Coupled Multiblock Wells in Oil Simulation
Authors: Behie A. , Collins D. , Forsyth P. A. , Sammon P. H. 
Published: December 2007

Abstract
A fully coupled treatment of oil wells that are completed in more than one zone results in a bordered matrix. This paper develops solution algorithms that incorporate existing direct and iterative (incomplete LU) solutions in a straightforward manner. Timings in scalar and vector modes on the Cray-1 for a typical reservoir simulation problem are presented.
Thermal Response of Polycrystalline Diamond Compact Cutters Under Simulated Downhole Conditions
Authors: Glowka D. A. , Stone C. M. 
Published: December 2007

AbstractAn analytical method is developed to predict temperatures in polycrystalline diamond compact (PDC) drag cutters under steady-state and transient downhole conditions. The method is used to determine mean wearflat temperatures for cutters under conditions used in previous experiments to measure cutter wear. A correlation between wearflat temperatures and cutter wear rates is demonstrated, and it is shown that, for the particular rock type tested, cutter wear rates increase significantly above 350°C [662°F]. The concept of a critical weight on bit, above which wear-flat temperatures exceed this value, is introduced. The effects of several parameters on the critical WOB are examined. These include cutter thermal conductivity, diamond layer thickness, rock properties, convective cooling, bit balling, and transient events such as bit bounce. Preliminary results of thermal stress modeling show that plastic yielding of the cutter structure can occur under certain downhole conditions.
Flow Visualization for CO2/Crude-Oil Displacements
Authors: Campbell Bruce T. , Orr Franklin M. 
Published: December 2007

Abstract
Results of visual observations of high-pressure CO2 floods are reported. The displacements were performed in two-dimensional (2D) pore networks etched in glass plates. Results of secondary and tertiary first-contact miscible displacements and secondary and tertiary multiple-contact miscible displacements are compared.
Three displacements with no water present were performed in each of three pore networks: (1) displacement of a refined oil by the same oil dyed a different color; (2) displacement of a refined oil by CO2 (first-contact miscible); and (3) displacement of a crude oil at a pressure above the minimum miscibility pressure. In addition, three tertiary displacements were performed in the same pore networks: (4) displacement of the refined oil by water, followed by displacement by the same refined oil dyed to distinguish it from the original oil; (5) tertiary displacement of the refined oil by CO2; and (6) tertiary displacement of crude oil by CO2. In addition, recovery of oil from dead-end pores, with and without water barriers shielding the oil, was investigated.
Visual observations of pore-level displacement events indicate that CO2 displaced oil much more efficiently in both first-contact and multiple-contact miscible displacements when water was absent. In tertiary displacements of a refined oil, CO2 effectively displaced the oil it contacted, but high water saturations restricted access of CO2 to the oil. The low viscosity of CO2 aggravated effects of high water saturations because the CO2 did not displace water efficiently. CO2 did, however, contact trapped oil by diffusing through water to reach, to swell, and to reconnect isolated droplets. Finally, CO2 displaced crude oil more efficiently than it did the refined oil in tertiary displacements. Differences in wetting behavior between the refined and crude oils appear to account for the different flow behavior.