bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Wavelet Analysis to Upscaling of Rock Properties
Authors: Chu Lifu , Schatzinger R. A. , Tham M. K. 
Published: December 2007

Summary
Although numerous upscaling techniques are reported in the literature, efficiently computing reasonably accurate equivalent rock properties from geological data at fine scale remains difficult. This is especially true for facies with multiple lithologies under multiphase-flow conditions. Because of the nature of multiscale heterogeneity inherent in petroleum reservoirs, the equivalent rock and flow properties will vary with the scales of heterogeneity. Therefore, upscaled properties under multiphase-flow conditions cannot be estimated without reference to the absolute scales of heterogeneity.
Wavelet analysis is a multiresolution framework; thus, it is well suited for upscaling rock and flow properties in a multiscale heterogeneous reservoir. The compact support property of the wavelet transform assures efficient computation. Choice of regularity provides a flexible way to control the smoothness of the resulting up-scaling properties.
In this study, we developed a new procedure to improve significantly the computational efficiency and accuracy of upscaling for generating equivalent rock and rock-fluid properties under various geological and flow conditions based on multiresolution analysis of wavelet transforms. Additionally, we explored a wavelet reconstruction method to provide a basis for downsampling fine-scale rock property fields from information at various levels of coarser scale. The beauty of the method is that because the equivalent properties at different length scales are computed recursively, the interdependent influences of the heterogeneities on the scales are included effectively. We demonstrate the method by successfully applying it to upscale interbedset and interfacies reservoir properties of Almond formation outcrops under multiphase-flow conditions.
Backflow in Twin-Screw-Type Multiphase Pump
Authors: Egashira Kazuyuki , Shoda Shinji , Tochikawa Tetsuro , Furukawa Akinort 
Published: December 2007

Summary
The performance of a twin-screw-type multiphase pump was investigated from the viewpoints of backflow in a gap along the twin-screw shafts and of scaleup parameters. Although both the backflow and the scaleup parameters have been recognized as important factors in developing multiphase pumps, they have not yet been clarified.
The twin-screw pump was equipped with pressure sensors, set in the multiphase-test facility, and experimented with under various conditions to clarify the relationship between backflow rates and factors such as differential pressure, gas-void fractions (GVF's), and the rotation speed of the shaft.
A physical model was proposed with the empirical relationship of pressure distribution along the screw, and was successfully associated with scaleup parameters, such as the geometrical data of the twin-screw pump. Then it was used successfully to simulate the backflow in twin-screw pumps on relatively broad experimental conditions, judging from the comparison between the model and the experimental data.
CFD Simulation of Single-Phase and Two-Phase Flow in Gas-Liquid Cylindrical Cyclone Separators
Authors: Erdal Ferhat M. , Shirazi Siamack A. , Shoham Ovadia , Kouba Gene E. 
Published: December 2007

AbstractThe petroleum industry has shown interest in utilizing the Gas-Liquid Cylindrical Cyclone (GLCC) separator as an alternative to the vessel-type separator. Thus, it is important to develop predictive tools for design and to improve the technology of the GLCC. Previous studies have resulted in mechanistic models capable of predicting the operational envelope for liquid carryover. However, these models do not address details of the complex flow field in the GLCC and related phenomena such as gas carry-under. This paper presents computational fluid dynamics (CFD) simulations of single-phase and two-phase flow in several GLCC configurations. The CFD simulations are compared with experimental data including tangential velocity profiles and tangential velocity decay. Good agreement is observed between the data and the simulations. An axisymmetric model for the GLCC is also developed. The axisymmetric simulations, which are computationally efficient, give good results as compared to the three-dimensional simulations. Preliminary two-phase flow simulations are also performed to predict the gas void fraction distribution in the GLCC.
Effects of Heterogeneity and Wetting on Relative Permeability Using Pore Level Modeling
Authors: Blunt Martin J. 
Published: December 2007

AbstractWe present a three-dimensional, capillary equilibrium based, pore level network model that computes relative permeability and capillary pressure for drainage and imbibition cycles. The model accounts for wetting layers in crevices of the pore space, cooperative pore filling and different contact angles. Arbitrary distributions of pore size with different spatial correlations are studied. We show that relative permeabilities for unconsolidated media can be represented in the model using spatially uncorrelated distributions of pore size, but that curves typical of consolidated rock can only be explained by allowing spatial correlation in the pore structure. We also study the effects of flow in wetting layers and different types of cooperative pore filling. This represents changes in contact angle from a completely water-wet system to a neutrally-wet rock. Relative permeability can be extremely sensitive to small changes in contact angle. In general, the residual non-wetting phase saturation decreases as the system becomes less strongly water-wet.
A Decision-Support System for Economic Analysis and Risk Assessment of Subsea Development Scenarios
Authors: Dyer N. J. , Ford J. T. , Tweedie A. 
Published: December 2007

Summary
The decision to develop a small (&lt; 100 million bbl) oil field in the U.K. sector of the central/northern North Sea requires a careful assessment of all aspects of the field-development plan—the reservoir model (reserves and production profile), capital and operating costs, and the current economic climate (oil price, interest rates, and tax regime). This paper describes the development of a knowledgebased software package that allows a "quick-look" assessment of the overall economics and risk profile associated with the development of small oil fields in this region. It is a modular system that uses a cost database, cost-adjustment algorithms, cash-flow analysis engine, and simulation procedures to integrate and analyze the impact of reservoir and production characteristics, costs [capital expenditures (Capex) and operating expenditures (Opex)], and economic factors on the decision to develop such a field. The production-system configurations considered by the system are (1) an unmanned wellhead platform tied back to a third-party platform for fluid pro- cessing/export; (2) a floating production, storage, and offloading system (FPSO) with oil export through a shuttle tanker and gas export through a tie-in to the existing North Sea gas pipeline infrastructure; and (3) a straight tieback from a group of subsea wells to a third-party platform for fluid processing/export.
Multiphase Flowmeter Successfully Measures Three-Phase Flow at Extremely High Gas-Volume Fractions—Gulf of Suez, Egypt
Authors: Leggett R. B. , Borling D. C. , Powers B. S. , Shehata Khalid , Halvorsen Martin , AboElenain Adel 
Published: December 2007

SummaryA multiphase flowmeter (MPFM) installed in offshore Egypt has accurately measured three-phase flow in extremely gassy flow conditions. The meter is completely nonintrusive, with no moving parts, requires no flow mixing before measurement, and has no bypass loop to remove gas before multiphase measurement. Flow regimes observed during the field test of this meter ranged from severe slugging to annular flow caused by the dynamics of gas-lift gas in the production stream. Average gas-volume fraction ranged from 93 to 98% during tests conducted on seven wells.The meter was installed in the Gulf of Suez on a well protector platform in the Gulf of Suez Petroleum Co. (Gupco) October field, and was placed in series with a test separator located on a nearby production platform. Wells were individually tested with flow conditions ranging from 1,300 to 4,700 B/D fluid, 2.4 to 3.9 MMscf/D of gas), and water cuts from 1 to 52%. The meter is capable of measuring water cuts up to 100%.Production was routed through both the MPFM and the test separator simultaneously as wells flowed with the assistance of gas-lift gas. The MPFM measured gas and liquid rates to within ± 10% of test-separator reference measurement flow rates, and accomplished this at gas-volume fractions from 93 to 96%. At higher gas-volume fractions up to 98%, accuracy deteriorated but the meter continued to provide repeatable results.
Formation Evaluation From Logging on Cuttings
Authors: Santarelli F. J. , Marsala A. F. , Brignoli Marco , Rossi Elio , Bona Nicola 
Published: December 2007

SummaryThis paper presents an overview of a vast research project called Formation Evaluation 2000, which was undertaken by Agip SpA and was aimed at characterizing in real time the formations encountered during drilling by means of measurements on drill chips. To date, the project has demonstrated the feasibility of obtaining representative values of P- and S-wave velocities, rock strength and deformability, permeability, porosity, density, residual fluid con- tent, and saturation. Further work is under way to determine the pore-size distribution, the thermal expansion coefficient, and the electrical resistivity of the rocks from measurements on cuttings.The paper presents the methodology used to systematically develop these technologies and illustrates the results obtained to date during the various sequences of the research, i.e., the primary design of the measurements, laboratory tuning, and field applicability. Furthermore, the paper presents a series of field cases in which these techniques were used, to highlight the industrial applications of such a package of measurements.
The Effect of Operating Decisions on Peripheral Waterflood Cash Flow
Authors: Wayhan D.A. 
Published: December 2007

A study of 20 Denver Basin peripheral waterfloods showed that the rate of waterflood oil recovery was influenced by the rate of water injection and by the water cycle volume; but principally it was influenced by waterflood timing. Discussed here are the magnitude and relative influence of these factors on waterflood cash flow and present worth. present worth. Introduction
Peripheral injection is frequently chosen as the best Peripheral injection is frequently chosen as the best means to waterflood a reservoir because the peripheral wells contribute less to current income. Also, the peripheral wells are often advantageously located downdip from the oil column. Because of their structural position they may have experienced some water influx or may have had water originally present in part of the sand section. part of the sand section. On the other hand, a peripheral waterflood is especially sensitive to operating decisions made before and during the life of the waterflood. If there are several rows of producers to be stimulated by one row of injectors, a slow waterflood start or a low injection rate can result in severely delayed waterflood response at interior producers. If large volumes of injected water are removed at close offsets to injectors, further delay or even a stalled waterflood may result.
The many completed or essentially completed peripheral waterfloods in the Denver basin provide an peripheral waterfloods in the Denver basin provide an excellent opportunity to study waterflood experience and to see how decisions concerning the major operating alternatives - that is, waterflood timing, the injection rate, and the water-cycle volume - have influenced peripheral waterflood cash flow.

Waterflood Recovery
An earlier paper reported the results of an analysis of waterflood recovery data from 23 Denver Basin waterfloods (20 were peripheral-type floods). The analysis indicated that ultimate recovery was influenced by the timing of a waterflood - the earlier a waterflood is conducted after reservoir pressure reaches the bubble point, the higher is the ultimate recovery. The reduction in recovery was shown to be due to shrinkage effects as expressed in Eq. 1.
(1) where
Erwf = waterflood recovery efficiency, percent,
Cr = relative conformance, percent,
E =
(This is water-drive recovery efficiency from Arps et al., assuming no pressure drawdown.)
Bob = reservoir volume factor at bubble point,
Bowf = reservoir volume factor at waterflood start.
Eq. 1 indicates that waterflood recovery will be reduced significantly if the reservoir volume factor is high and if a waterflood is delayed until most of the primary oil has been produced. primary oil has been produced. Table 1 shows operating data from 23 waterfloods.
P. 1320
Polymer Gelants for High Temperature Water Shutoff Applications
Authors: Bryant Steven L. , Bartosek Martin , Lockhart Thomas P. , Giacca Diego 
Published: December 2007

Abstract
Polymer gelants are a well established means for shutting off water in lower temperature formations, but extending their application to hot reservoirs (&gt;80°C) presents a number of technical challenges, particularly in matrix reservoirs. Achieving reliable high temperature performance requires programmable gelation delay, good injectivity, good propagation of gelant components and durability of the permeability reduction. The performance of a gelant against these criteria is dictated by a relatively small set of chemical and physical phenomena. A discussion of these phenomena provides a rational background for assessing the advantages and disadvantages of currently available gelants. This also helps to identify the best avenues for improving polymer gelant systems. This approach is particularly relevant when seeking gelants for high temperature matrix applications, because increased temperature renders it much more difficult to satisfy the four performance features simultaneously.
A Multiply-Fractured Horizontal Well in a Rectangular Drainage Region
Authors: Chen Chih-Cheng , Raghavan Rajagopal 
Published: December 2007

Summary
We examine the productivity of a multiply-fractured well in a reservoir that is in the form of a rectangle. The properties of the individual fractures (length, conductivity, skin, etc.) are entirely arbitrary. The fractures are assumed to be parallel to one of the sides of the rectangle and maybe either parallel or perpendicular to the horizontal well. The primary objective of this work is to outline a computationally-efficient scheme to compute well productivity. This objective yields a simple method to incorporate this completion scheme in reservoir-simulation models. It should permit an engineer to understand interactions between the fractures in the presence of boundaries. The model also permits us to compute pressure distributions under depletion conditions for single-phase oil and gas reservoirs. Further, it provides for a realistic design of this completion scheme.
It is to be emphasized that the problem we consider is a nontrivial one in that flow to a single vertical fracture of finite conductivity in a rectangular drainage area is yet to be modeled successfully.
Conditions for Determining Areal Permeability Distribution by Calculation
Authors: Nelson R. William 
Published: December 2007

NELSON, R. WILLIAM, GENERAL ELECTRIC CO., RICHLAND, WASH.

Introduction
Methods for determining permeability presented by W. D. Krugers in a paper entitled "Determining Areal Permeability Distribution by Calculation" have considerable merit. They can be expected to contribute significantly to analysis of flow in heterogeneous systems. Some rather subtle yet important conditions must be met, however, to assure that the computed permeabilities are correct. The conditions which insure a unique permeability distribution may have been overlooked in the method as proposed and presented in the subject paper. The subtlety of the special requirements may permit good agreement between computed and measured pressures in the reservoir; but the computed permeability may still be in error. The general theory and discussion to the requirements for a unique determination of the permeability distribution are presented elsewhere in more detail. Accordingly, only major features will be presented here in the notation of Kruger.

GENERAL DESCRIPTION OF REQUIREMENTS
A brief mention of the route to be followed in showing the special requirements may be helpful. The equation to be solved is a quasilinear, first-order, partial differential equation in the unknown permeability. This equation can be solved through an extension of Lagrange's method by reduction to a system of subsidiary ordinary differential equations. Through consideration of the identity of one of the Lagrange subsidiary differential equations with the stream function, a special interrelationship can be shown. The interrelationship has special significance with respect to the boundary condition. If the boundary function satisfies part of the subsidiary differential equation, no unique solution for the permeability distribution exists. In the physical problem this requirement for uniqueness indicates that the permeability measurements used as a boundary condition can not be along a stream tube. The boundary condition must be along a line, or series of lines, which completely traverse the region and pass through every stream tube.

DERIVATION OF SPECIAL REQUIREMENTS ON THE BOUNDARY CONDITION
If the velocity components in the directions of increasing x and y are vx and vy, the equation for the streamlines is
dx/vx = dy/vy ..............................(1)
Eq. 1 of Kruger's paper can be expanded to give:
.............................(2)
khEq. 2, when is the dependent variable, is a quasilinear first-order partial differential equation. The analytical method of solution is described in several texts with Goursat's treatment as translated by Hedrick and Dunkel, being very readable and complete. Eq. 2 is reducible to the system of subsidiary differential equations.
..............................(3)
Through assuming the form of the solution to be
......(4)
where F is an arbitrary function of two independent integrals of the system of Eq. 3.
SPEJ
P. 223^
Adsorption of Carboxylic Acids on Reservoir Minerals From Organic and Aqueous Phase
Authors: Madsen Lene , Lind Ida 
Published: December 2007

Summary
Adsorption of organic acids onto North Sea chalk and pure minerals from a hydrocarbon phase and an aqueous phase show that the maximum adsorption is larger for calcite than for silicate surfaces in the hydrocarbon phase. The opposite is observed, however, in the aqueous phase. This suggests that the available silicate surfaces and oil/water ratio may play a role in the wettability of chalk.
Extended-Reach Composite-Materials Drillpipe
Authors: Hareland Geir , Lyons W. C. , Baldwin D. D. , Briggs G. M. , Bratli R. K. 
Published: December 2007

Summary
This paper presents a new composite drillpipe design that allows for an increase in the drilling reach of high-angle, directional wells. Horizontal reach is greatly limited by resisting friction forces that are created by the interaction between the drillstring and the lower side of the borehole. As the drillstring is advanced further into a highly directional borehole, the resisting friction forces give rise to ever-increasing applied-torque and axial (push)-force requirements. The gravitational forces (i.e., drillstring weight) dominate the buoyancy forces in nearly all modern drillstring designs that are currently used in highly directional drilling operations. These dominating gravitational forces create reaction forces between the drillpipe and the borehole wall. The reaction forces, when multiplied by the coefficient of friction between the drillstring and the borehole, yield tangential surface forces on the drillstring (normal to, and parallel with, the pipe axis). These forces resist the applied torque that rotates the drillstring and the applied axial (push) force that advances the drillstring. The new composite drillpipe design discussed in this paper reduces the specific weight of the drillpipe so that it will have nearly neutral buoyancy in 15.4-lbm/gal drilling muds. With this reduction in drillpipe specific weight, a drillstring with this new design will have greatly reduced gravitational forces and, in turn, greatly reduced resisting friction forces. This design feature allows the applied torque and axial force to be more effective, thus allowing greater extended-reach capabilities. It is estimated that the current extended horizontal-reach approximate limit of 10 km could be increased to 15 km or more with the application of this new composite drillpipe design. Such an increase in reach would have an important impact on the development of oil and gas fields that are economically dependent on advanced directional drilling technologies. This new composite drillpipe technology has been extensively bench and field tested and has been successfully used in short-radius drilling operations. The design features of the proposed light-weight composite drillpipe are discussed and compared to current horizontal drilling operational requirements (using a steel drillpipe). The new light-weight designs can be used with either steel or titanium tool joints (with a filament-wound composite-tube body structure between the tool joints). The drillpipe may be fabricated in either 30- or 42-ft lengths. Engineering feasibility studies have shown that this new light-weight composite drillpipe will be economical to fabricate and should provide significant economic advantages in the development of oil and gas fields requiring extensive directional drilling operations.
Harnessing Information Technology To Facilitate Change
Authors: Chevallier Jean 
Published: December 2007

Summary
This paper provides a business perspective of how harnessing information technology (IT) can facilitate change, especially in the oil and gas industry. The oil and gas industry has benefited significantly by leveraging developments in IT for applications that reduce the cost of oil exploration; reduce the time required to perform complex tasks; and link people and information, thereby enabling virtual teams. Typical examples of virtual teamwork are three-dimensional (3D) seismic surveys and million-gridblock reservoir simulations. To implement information-age solutions with global access and anytime availability, one must be aware of security, remote connectivity, and information management issues. Overcoming these issues can be an opportunity for oil and gas industry IT solutions organizations. Future developments in software, Intranet, powerful clients, massively parallel processing (MPP), and asynchronous transfer mode (ATM) will further enhance IT's capability to facilitate change in the oil and gas industry. IT already has played a significant role in the revival of this industry and will continue to do so into the 21st-century.