bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpretation and Theoretical Modeling of Scale-Inhibitor/Tracer Corefloods
Authors: Sorbie K. S. , Wat R. M. S. , Todd A. C. 
Published: December 2007

SummaryThis paper describes a theoretical approach to determine the inhibitor dynamic adsorption isotherm from coreflood experiments. The main feature of the isotherm that contributes principally to the long squeeze life is highlighted. The problems of modeling near-well squeeze treatments and an improved simulator are discussed.
Optimal Fracture Stimulation of a Moderate-Permeability Reservoir — Kuparuk River Unit, Alaska
Authors: Pearson C. M. , Bond A. J. , Eck M. E. , Lynch K. W. 
Published: December 2007

SummarySixty-five percent of the reserves of the Kuparuk River field, the second-largest producing oil field in the U.S., is contained in a 20- to 80-md-permeability sandstone. This paper provides details of stimulation design advances made over the past 3 years in this formation. The design steps for optimizing fracture treatments in a moderate-permeability formation require primary emphasis on fracture conductivity rather than on treatment size or fracture length. This philosophy was used for the 140 new wells documented in this paper. Treatment size was gradually increased once a commensurate increase in fracture conductivity was obtained. Applying the new design to the refracturing of 88 producing wells in the field resulted in an incremental 40, 000 BOPD, a significant portion of the field's 300, 000 BOPD.
Estimation of Capillary Pressure and Relative Permeability Functions From Centrifuge Experiments
Authors: Nordtvedt J. E. , Mejia Gerardo , Yang Pin-Huel , Watson A. T. 
Published: December 2007

SummaryA method to estimate capillary pressure and relative permeability curves simultaneously from transient, multirate centrifuge experiments performed on homogeneous rock is presented. The unknown functions are represented with B-splines, and the number of knots and coefficient values are selected through a regression-based procedure. The method is demonstrated by use of experimental data for dolomite and sandstone samples with air/water and oil/water fluid systems. An analysis of the accuracy of the estimates is presented. The capillary pressure curve and regions of both relative permeability curves can be estimated accurately.
Recent Advances in the API Quality Program
Authors: Gollhofer F. R. 
Published: December 2007

Summary
The API now has more than 3 years’ operating experience in licensing manufacturers under the API Quality Program. The API evaluation procedures, described in this paper, provide consistency in evaluation and should allow full participation of petroleum equipment suppliers in the worldwide market during the 1990's and into the 21st century. The program's flexibility will allow it to cope with significant changes resulting from the planned European Common Market's "Global Approach to Certification and Testing" scheduled to occur in 1992.
Scale Prediction and Laboratory Evaluation of BaSO4 Scale Inhibitors for Seawater Flood in a High-Barium Environment
Authors: Mazzolini E. I. , Bertero Luigi , Truefitt C. S. 
Published: December 2007

Summary
The potential for scale formation after seawater injection must be carefully studied when a new oil field is being developed in order to provide proper input data for the basic engineering design. This paper presents the results of a study of several facets of scale occurrence and control for a developing North Sea field characterized by a high-salinity, high-barium (up to 1, 000 ppm) formation brine. The results justify consideration of new technologies, such as treatment of the seawater to reduce the sulfate content.
Multilayer Flowmeter Testing Combined With 3D Field Modeling To Enhance the Ameland Field Development
Authors: Vogelij Harry N. J. , Leach Michael J. , Kapteyn Pieter K. A. 
Published: December 2007

Summary
To assess the level of differential layer depletion in the Ameland gas field, production logging surveys were conducted and interpreted with a multilayer testing (MLT) technique to derive layer pressures. Results were used in a 3D simulation study showing that layer pressure differentials were controlled by offtake redistribution and could be sustained only if vertical permeabilities in siltstone/shale layers were extremely low. Units in undrained flank blocks could be underdepleted by as much as 10 MPa and drilling these blocks would increase developed reserves.
High-Pressure Well Design
Authors: Krus Harrle , Prieur Jean-Marie 
Published: December 2007

Summary
Shell U.K. E&P (Shell Expro), operator in the U.K. North Sea on behalf of Shell and Esso, plans to drill 20 high-pressure wells during the next 2 years. The well design is based on new standards developed after the U.K. Dept. of Energy restriction on high-pressure drilling in the autumn of 1988. Studies were carried out to optimize casing design and drilling performance on these wells. Several casing schemes, including a slim-hole option, were analyzed. The material specifications for casing and drillpipe were reviewed to ensure that they met the loads imposed during drilling, well-control, and well-testing operations. The requirement for sour-service material was weighted against possible H2S adsorption by the mud film. As a result, a new drillstring and two high-pressure casing schemes have been specified. The high-pressure casing scheme used depends on the maximum expected surface pressure.
Blowout Risk Analysis of Gas-Lift Completions
Authors: Grassick D. D. , Kallos P. S. , Dean Simon , King S. D. J. 
Published: December 2007

Summary
A dynamic risk analysis was performed on four different gas-lift completions using a computer simulator. Results are presented to allow comparison of the designs in terms of blowout risk and minor leakage during production and to provide insight into the effect of critical components and operations on the overall well safety.
Specific Surface and Fluid Transport in Sandstones Through NMR Studies
Authors: Borgia Glullo C. , Brighenti Giovanni , Fantazzini Paola , Fanti Gian D. , Mesini Ezio 
Published: December 2007

SummaryRecent nuclear magnetic resonance (NMR) studies in water-saturated porous media showed that magnetic resonance relaxation of 1H nuclei is a powerful tool for studying the interplay between geometry and fluid transport. Proper combinations of spin-lattice relaxation lifetime, T1, and porosity allow permeability to be predicted. T1, as defined here, provides a bridge between structural and transport properties because it can be viewed as a dynamically weighted (by diffusion) version of the specific surface. In this paper, we probe this role of T1 for a suite of clean sandstone samples in which, besides permeability and porosity, specific surface by mercury porosimetry and the formation resistivity factor (FRF) also have been measured. We studied the correlations among these properties and found that the ability of T1 to estimate permeability is a result of its linear dependence on the PV-to-surface ratio, Vp/S. For clean sandstone rocks, one may view the reciprocal electrical resistivity formation factor, 1/F, as representing the transport properties and the factor T12 as representing the distance scale, giving k∝T12/F. A suitable analysis of the spin-lattice relaxation curve can yield an estimate of an appropriate specific surface pertinent to permeability because it indirectly accounts for the connectivity of the pore space. This NMR approach constitutes a useful technique for a better reservoir characterization and for studying some elusive properties of natural porous media in a nondestructive manner. Theoretical and phenomenological correlations among permeability, porosity, FRF, and PV-to-surface ratio can be established.
Use of Dip and Azimuth Horizon Attributes in 3D Seismic Interpretation
Authors: Mondt Jaap C. 
Published: December 2007

Summary
Through a combination of interactive interpretation and powerful automated tracking, horizons can be interpreted efficiently on every available trace in a 3D seismic survey. Horizon-related seismic attributes then are extracted and processed to enhance interpretation. Dip and azimuth attributes play an important role in this respect. They enable an interpreter to map subtle trace-to-trace variations in event time or reflection character. Areal pattern analysis leads to detailed interpretations of structure (faults and flexures) and stratigraphy (channels and fans) and to the recognition of geophysical artifacts (statics, acquisition effects, and noise).
Potential of Repeated Polymer Well Treatments
Authors: Lakatos István , Lakatos-Szabó Julianna , Munkácsi István , Tröböczki Sándor 
Published: December 2007

Summary
This paper analyzes field results obtained by routine application of a polymer/silicate well treatment technique at the Algyó-2 field in Hungary. First, the reservoir is described briefly; then, the basic concept of the method is outlined. Reference is made to the multifunctioning chemical mechanism of gelation and the favorable rheological properties of the treating fluids that jointly result in a highly selective placement and an efficient permeability reduction in the target reservoir space. Application of the method 17 times in 16 producing wells yielded more than 90 000 Mg of incremental oil production. Typical well behaviors also are illustrated. Finally, the potential of repeated treatments is discussed, taking laboratory and field results into account.
Three-Fluid Wetting Transitions and Their Effects on Three-Phase Flow Through Porous Media
Authors: Smith Duane H. , Covatch Gary L. , Lowry William E. 
Published: December 2007

Summary
From phase and wettability studies on bulk phases, we predicted the fluid-fluid-fluid dispersion morphologies that could be expected for ex-situ dispersions (formed before injection) and for the dispersions after they were injected into a porous medium. From videomicroscopic studies of the flow of the dispersions through an etched microvisual cell, we determined the actual morphologies of the dispersions during flow. Three different wettability conditions and three different morphologies of flowing dispersions were observed.
Stochastic Modeling of Reservoir Architecture for Field Management
Authors: Taheri Mojtaba 
Published: December 2007

Summary
This paper outlines a probabilistic geologic modeling system developed to describe and characterize heterogeneous fluvio-deltaic sandstone reservoirs in the San Diego area, Orinoco belt, eastern Venezuela. The model uses field, well, and laboratory data to simulate synthetic stratigraphic sections in different directions and to delineate the geometry, continuity, and anisotropy of sand bodies and the regional distribution of internal reservoir properties (porosity, permeability, and hydrocarbon saturation). From a stochastic viewpoint, the model introduces the following improvements: (1) a Poisson process to predict the occurrence of sedimentary sand bodies in the stratigraphic sections, (2) facies proportion curves to condition the occurrence of sand bodies on the depositional environments, (3) Latin hypercube sampling (LHS) as a more precise sampling method in simulation, and (4) a geometric computer modeling technique (QUADTREES) to calculate the reservoir properties and to delineate complex geometries and effective drainage areas. These techniques are illustrated by use of field data from a pilot development in the San Diego area.
Novel Simulation Techniques Used in a Gas Reservoir With a Thin Oil Zone: Troll Field
Authors: Henriquez Adolfo , Apeland Odd J. , Lie Øystein , Cheshire Ian 
Published: December 2007

Summary
Choice of production strategy in modem reservoir management relies heavily on numerical simulation. Large fields may require prohibitively large computer times. New techniques were developed to save computer and engineering time: local grid refinement with small timesteps and flux boundary conditions for simulating regions of special interest. The combined use of these techniques allowed flexible, non-time-consuming, user-friendly reservoir simulation of a variety of reservoir management scenarios for Troll field.
Casing Deflection and Centralizer Spacing Calculations
Authors: Juvkam-Wold H. C. , Wu Jiang 
Published: December 2007

Summary
Equations for calculating casing deflection and determining casing centralizer spacing are derived for 1D, 2D, and 3D wellbores. The load-deflection differential equation for a span of casing between two centralizers is solved by use of the "fixed-ends" boundary condition. The combined effect of casing weight and axial tension on casing deflection is analyzed in detail.
Pressure Transient Analysis of Naturally Fractured Reservoirs with Uniform Fracture Distribution
Authors: Kazemi H. 
Published: December 2007

Abstract
An ideal theoretical model of a naturally fractured reservoir with a uniform fracture distribution, motivated by an earlier model by Warren and Root, has been developed. This model consists of a finite circular reservoir with a centrally located well and two distinct porous regions, referred to as matrix and fracture, respectively. The matrix has high storage, but low flow capacity; the fracture has low storage, but high flow capacity. The flow in the entire reservoir is unsteady state.
The results of this study are compared with the results of the earlier models, and it has been concluded that major conclusions of Warren and Root are quite substantial. Furthermore, an attempt has been made to study critically other analytical methods reported in the literature.
In general, it may be concluded that the analysis of a naturally fractured reservoir from pressure transient data relies considerably on the degree and the type of heterogeneity of the system; the testing procedure and test facilities are sometimes as important. Nevertheless, under favorable conditions, one should be able to calculate in-situ characteristics of the matrix-fracture system, such as pore-volume ratio, over-all capacity of the formation, total storage capacity of the porous matrix, and some measure of matrix permeability.

Introduction
The analysis of flow and buildup tests for obtaining in-situ characteristics of oil and gas reservoirs has received considerable attention in the past decade.
Most of the available techniques result in reliable conclusions in macroscopically homogeneous reservoirs or in the homogeneous reservoirs with only certain types of induced and/or inherent heterogeneity (such as wellbore damage, etc.).
Discriminant Analysis and Neural Nets: Valuable Tools To Optimize Completion Practices
Authors: Nitters Gerrit , Davies D. R. , Epping W. J. M. 
Published: December 2007

AbstractThis paper describes the application of multi-variate statistical techniques, discriminant analysis and neural networks in identifying drilling and other completion practices that impact on well productivity. Discriminant analysis determines whether a well can be assigned to a group of wells, on the basis of a number of common characteristics and using linear multivariate correlations. Neural nets enable the use of nonlinear correlations for such a classification.In this study, 47 gas wells from two fields were classified into three groups:Group 1: no production;Group 2: production below 5900 std m3/h (5 MMscf/D);Group 3: production over 5900 std m3/h (5 MMscf/D).The variables used in the discriminant analysis included parameters such as completion type, total height of the perforated interval, mud weight, drawdown during perforation, type of mud and perforation size.The study has identified and, to some extent, quantified those parameters that either adversely or favourably affect well productivity. The results can be used to adjust operational procedures to maximize well productivity. The parameters identified as increasing productivity reflect, for the most part, sound engineering practices.Application of neural nets enables further quantification of the effects of petroleum engineering parameters on well productivity and is being developed to make it possible for the most economical preventive and remedial measures to be selected.However, statistical techniques are applicable only when a sufficiently large data base is available, i.e., they are suitable for reasonably large and fairly mature fields and/or areas.
Computation of the Pseudoskin Factor for a Restricted-Entry Well
Authors: Ding Wenzhong , Reynolds Albert C. 
Published: December 2007

Summary
Papatzacos and Vrbik proposed formulas for calculating the pseudoskin factor from a restricted-entry well in a single-layer homogeneous reservoir. This work extends their simple analytical formulas to a multilayer case. It is shown that, in applying the new equations, the effective average vertical permeability Yeh and Reynolds defined should be used.
Simulation of Heterogeneous Sandstone Experiments Characterized With CT Scanning
Authors: Ganapathy Seetharaman , Wreath Dana G. , Lim Min T. , Rouse Bruce A. , Pope Gary A. , Sepehrnoori Kamy 
Published: December 2007

Summary
Coreflood experiments in naturally heterogeneous sandstone outcrop cores were conducted 1ijld simulated. Displacements included waterfloods and polymer floods containing tracers for oil or water during single-phase and two-phase flows. Displacements of viscous polymer solution were unstable. The cores were characterized by air permeability measureIllentson each square centimeter of each face and by computerized tomography (CT) scans of core cross sections spaced 1 cm apart along the core length. Characterization data were used for fine-grid simulations. The agreement between the experiments and simulations is good. Sipmlations with coarser-grid physical descriptions then were made by use of effective properties.
Optimizing Production by Fluid and Rock Studies for the Stevens Sands, North Coles Levee Field, Kern County, California
Authors: Underdown David R. , Schultz Douglas J. , Marino Anthony W. , Miranda Roger , Kullman John M. 
Published: December 2007

Summary
Drilling and completion fluids optimized by petrographic and capillary suction time (CST) analyses improved well productivity for the lower Stevens sands in Kern County, CA. The fluid systems allowed drilling of a gauge hole, which was essential to a good cement bond and a successful fracture stimulation of the low-permeability formation.
Microseismic Logging: A New Hydraulic Fracture Diagnostic Method
Authors: Mahrer Kenneth D. 
Published: December 2007

Summary
Hydraulic fracture treatments and fluid injections into fractured wells induce a useful cloud of microseismic sources in the fractured zone. This induced seismicity can last for hours after pumping and pervades the fracture. The source-size population distribution ranges from a countable (50 to 500) number of large, individually distinguishable events to a din of background events. Each source radiates wave motion, which can be recorded only in and near the fracture. A new method uses these motion data, recorded in the cased treatment well, to determine the fracture height and azimuth. The height is found by delineating the location and vertical extent of a spatial anomaly in the background-motion data. The azimuth is derived from the particle-motion polarization of the largest events of the microseismic event population. This paper describes the method, exemplary data sets, theory, and simulations that substantiate this method.
Core-Based Prediction of Lithologic Stress Contrasts in East Texas Formations
Authors: Thiercelin M. J. , Plumb R. A. 
Published: December 2007

SummaryThis paper presents an evaluation of two fundamentally different stress models: an elastic model, which is based on linear transverse isotropic elasticity, and a failure model, which is based on the concept that rocks are in an equilibrium state of shear failure. The models arc evaluated by using physical parameters measured on core, pore pressure, and in-situ stress data from the Gas Research Institute (GRI) Staged Field Experiments (SFE's) in east Texas. It is shown that the elastic and failure models provide satisfactory predictions for most of the lithologies encountered. However, the failure model is more accurate for predicting stress in soft shales. An example of stress predictions based on log-derived elasticity parameters that gives stress estimations comparable to core-based predictions is also shown.
Comparisons of Empirical Viscous-Fingering Models and Their Calibration for Heterogeneous Problems
Authors: Fayers F. J. , Blunt M. J. , Christie M. A. 
Published: December 2007

Summary
This paper reviews the formulation and parameters for three principal empirical viscous-fingering models: the Koval, Todd and Longstaff, and Fayers methods. All three methods give similar levels of accuracy when compared with linear homogeneous experiments, but they differ in performance in 2D applications. This arises from differences in the formulation of the total mobility terms. The superiority of the Todd and Longstaff and Fayers methods is demonstrated for 2D and gravity-influenced flows by comparison with experiments and high-resolution simulation. The use of high-resolution simulation to calibrate empirical models in a systematic manner is described. Results from detailed simulation demonstrate the sensitivity of empirical model parameters to viscous/gravity ratio, recovery process [secondary, tertiary, or water-altemating-gas (WAG)], and geological heterogeneity. For large amplitude heterogeneities with short correlation lengths, the accuracy of the empirical models is shown to be less satisfactory, but improved by the addition of a diffusive term.
Wettability Studies at the Pore Level: A New Approach by Use of Cryo-SEM
Authors: Robin Michel , Rosenberg E. , Fassi-Fihri Omar 
Published: December 2007

Summary
Cryo-scanning electron microscopy (Cryo-SEM) is used to study the wettability of reservoir rocks from fluid distribution at irreducible water saturation, Swi, and residual oil saturation, Sor. Results on mixed-wettability cores point out the importance of composition, distribution, and accessibility of minerals in determining the macroscopic behavior of the rocks. For the studied samples, wettability of sandstones is related to the presence of kaolinite, while wettability of carbonates seems to be related to pore-size distribution.
Well-Test-Model Recognition With Laplace Space
Authors: Bourgeois Marcel J. , Horne Roland N. 
Published: December 2007

Summary
This study presents a mathematical background that justifies a new use of Laplace space in well-test analysis. It enables us to perform the whole parameter identification (CD S, k, h, etc.) in Laplace space or at least gives us a powerful tool to treat pressure data to recognize the model to use for parameter identification in real space. It shows how the Laplace transform of pressure can be plotted with exactly the same behavior as the real pressure function so that the plots keep their familiar shape. The coefficients of the dimensionless parameters also remain the same, which enables us to display a new set of characteristic and easily understandable type curves in Laplace space. The mathematical background also sheds light on use of the Laplace transform to deconvolute flow rates by modifications of earlier techniques that were extremely sensitive to noise in the data. The Laplace-space approach provides an entirely new way of examining and understanding well-test results. It has been applied successfully to noisy, simulated data and real field data where conventional interpretation could not illuminate ambiguities.