bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pore Combination Modeling: A Technique for Modeling the Permeability and Resistivity Properties of Complex Pore Systems
Authors: Myers M. T. 
Published: December 2007

Abstract
An empirical model is presented for the flow properties of rocks which is consistent with Archie’s equation1. The parameters for the important pore types for both elastics and carbonates are obtained from fits of measured formation factors to thin section point count data. These same parameters are used to model the saturation dependence and permeability.
Representation of Fault Sealing in a Reservoir Simulation: Cormorant Block IV, UK North Sea
Authors: Bentley M. R. , Barry J. J. 
Published: December 2007

Abstract
The representation of structural complexities in numerical reservoir simulations is cumbersome and often over-simplified. The introduction of leak paths across faults is particularly subjective, because patterns of fault sealing are generally not described by the geologist.
A procedure is presented here which models fault sealing capacity, and allows potential leak, paths to be located, ranked and incorporated into the simulation model. The procedure involves the semi-quantitative modelling of fault sealing assuming clay smear and shale juxtaposition to be the primary sealing mechanisms. The capacity for sealing along faults cutting representative reservoir sequences is described on clay smear ‘type panels’. Information from the type panels is used to map out variations in fault sealing capacity along individual fault planes, allowing potential leak paths to be located and ranked.
The reservoir simulation employs a coarse, curvilinear grid, designed to honour the structural configuration of the reservoir but facilitate fast processing times. Ranked leak paths are introduced into the simulation model during history matching to constrain cross-flow between reservoir
sub-compartments. This leads to a matched simulation model, and also provides a calibration of the fault seal model against production data.
The procedure of combining the reservoir simulation and fault seal models illustrates the benefits of an integrated production geology/reservoir engineering approach to reservoir modelling.
Testing of Horizontal Gas Wells in Anisotropic Naturally Fractured Reservoirs
Authors: Ng M. C. , Aguilera R. 
Published: December 2007

Abstract
Analytical solutions that include real gas pseudo pressures are presented for pressure drawdown and buildup analysis of horizontal wells in anisotropic reservoirs with tectonic, regional or contractional natural fractures. The reservoir might be limited by parallel sealed boundaries. The solutions have been obtained with the use of Fourier and Laplace transforms. Wellbore storage has been handled using a finite difference scheme of the convolution integral.
These solutions have led to the identification of the following flow periods: Wellbore storage which might mask many of the subsequent flow periods.A first radial flow period at early times from the natural fractures into the horizontal well. This occurs in a vertical plane.A transition period due to flow from the matrix into the natural fractures.A second radial flow period, still in a vertical plane, which starts when pressures in matrix and fractures reach an equilibrium. This pressure equilibrium can also be attained at a later flow period in which case the second radial period would not be present.A linear flow period when the pressure transient reaches the upper and lower boundaries of the reservoir.A pseudo radial flow period towards the wellbore in a horizontal plane.A linear flow period when the pressure transient reaches the outer parallel boundaries.
It is concluded that recognition of these flow periods can lead to calculation of pi or p*, permeabilities in the x, y and z directions, storativity ratio omega, average distance between natural fractures, fracture porosity, fracture aperture, skin, and pseudo skin due to vertical and horizontal partial penetration. Calculations are illustrated with an example.
The Geological Modeling of Effective Permeability in Complex Heterolithic Facies
Authors: Norris R. J. , Lewis J. J. M. 
Published: December 2007

ABSTRACT
Conventional methods of quantitative reservoir characterization are inappropriate when confronted with the complex ripple-scale (millimetric to centimetric scale) intercalations of sand and shale that are characteristic of heterolithic facies. This paper presents a new methodology for quantifying single-phase fluid flow behaviour in heterolithic facies by defining, for discrete heterolithic lithofacies types, effective permeabilities at Representative Elementary Areas (REAs). REA graphs are defined by calculating effective permeabilities at increasing scales, using the renormalization approach. Given that effective permeability values in these facies are dominated by sand connectivity, these REAs are based on binary sand-shale indicator maps derived from constant-scale photography at outcrop. The heterolithic facies studied produce REAs at characteristic scales of around 20,000 cm2. REA based effective permeabilities in different directions show comparable areal dimensions, but significantly different permeability values. REA based effective permeabilities can subsequently be modelled in inter-well volumes through the use of various indicator based pattern recognition procedures. A methodology is presented for developing realistic "training" patterns of heterolithic lithofacies through outcrop photography.
Fast Generation of Grid-Block Permeabilities for the Analysis of Uncertainty on Reservoir Simulations
Authors: Gomez-Hernandez J. J. , Journel A. G. 
Published: December 2007

Abstract
Monte-Carlo analysis of uncertainty on reservoir performance is very expensive. It involves: first, the generation of multiple permeability fields at the scale of the measurements; second, the average of these permeabilities to obtain equivalent grid-block permeabilities at a scale that can be handled by current numerical reservoir simulators, and third, the simulation of flow on these scaled-up fields. Although the most expensive step is, generally, the third one, there is still time and effort invested in the first two steps. An approach is proposed for the fast generation of equivalent grid-block permeabilities directly from the measurements honoring both local information and structural information. The approach is based on a geostatistical model for the joint spatial variability of both measured permeabilities and grid-block permeabilities.
Modeling Geological Heterogeneities and Its Impact on Flow Simulation
Authors: Suro-Pérez V. , Ballin P. , Aziz K. , Journel A. G. 
Published: December 2007

Abstract
A single algorithm is proposed for the numerical modeling of geological facies and corresponding petrophysical properties. All reservoir parameters, whether categorical such as lithofacies type or continuous such as permeability are coded and processed as a series of binary indicator variables. Stochastic modeling of the reservoir is based on Indicator Principal Component Kriging and the sequential simulation principle. The resulting alternative and equiprobable reservoir models honor the available information at wells and their statistics. These reservoir models are then used to investigate the impact of geological heterogeneities on flow performance prediction in a water-flood scheme. Analysis of various production parameters (cumulative oil production, cumulative water oil ratio and breakthrough times) indicates that they are more sensitive to the geological architecture of the reservoir than to details of the statistical distributions of petrophysical variables. Direct modeling of permeability across lithofacies, i.e. ignorance of the geological architecture, may lead to severe inaccuracy in reservoir performance prediction, particularly after the first transient years of production.
The Effect of Large-Scale Heterogeneities on the Performance of Waterdrive Reservoirs
Authors: Barthel R. 
Published: December 2007

ABSTRACT
A significant fraction of the reservoir volume may remain unswept during a water-oil displacement. Potentially recoverable oil in a clastic reservoir may be bypassed as a consequence of poor sand connectivity or large contrasts in permeability between neighbouring sandbodies. Such conditions typically occur in fluvial deposits (poor connectivity) and channel-fill/mouthbar combinations (large permeability contrasts).
To investigate the effect of the properties of these reservoirs on waterdrive efficiency, simulations of prototype reservoirs have been carried out. All waterdrives investigated were flank waterdrives, representative of North Sea reservoirs.
The reservoirs characterised by sandbodies with different ranges of permeability could be modelled with a relatively coarse grid. The effects of sandbody geometry, well spacing and permeability contrast on the displacement efficiency were investigated. It was found that in some cases the additional recovery from an infill well, located in a poorly swept, low-permeability sand, can be as high as 7% of the STOIIP contained between the initial wells.
Modelling the complicated networks of channel sands surrounded by shales encountered in fluvial deposits requires a much finer grid with a larger number of gridblocks than modelling large sand bodies. To accommodate simulation models with a large number of gridblocks a highly simplified special-purpose simulator was developed. This simulator neglects those physical mechanisms that have only a minor effect on the displacement process considered and can handle models with more than 100 000 gridblocks easily. For these fluvial reservoirs the effects of channel density, alternative channel distributions (reservoir architecture) and of permeability contrasts between channels were investigated. It was found that at low channel densities (average nett-to-gross ratio less than 25%), oil tends to be bypassed because of poor connectivity and that the overall performance depends on the reservoir architecture. At higher channel densities, permeability contrasts can be a major cause of bypassing.
Energy Resources Engineering - A New Concept In Engineering Education
Authors: Schoeppel R.J. , Comer A.G. , Rowe A.M. , Sebesta H.R. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
To meet present and future competition, many oil companies are expanding their operations in the direction of becoming totally integrated energy companies. Their activities range from exploration and development of petroleum reservoirs, tar sands and oil shales, to diversification in energy associated industries such as those producing coal or nuclear fuel. In light producing coal or nuclear fuel. In light of these developments, the public image of an "oil company" is changing from strictly a petroleum alignment to one that is concerned with the nation's overall energy requirements and uses.
Petroleum engineers are well trained to exploit conventional petroleum reservoirs; however, the development of the additional sources of energy now will require engineers with a different type of training. In order to provide for these new technical manpower needs, a program has been developed at Oklahoma State University that integrates all of the energy related aspects of the various classical engineering fields into one discipline. This new concept in education, called Energy Resources Engineering, encompasses training in the production, processing, conversion, transportation, processing, conversion, transportation, storage and utilization of energy. It is the purpose of this paper to review the development of the program in Energy Resources Engineering at OSU and to present a discussion of experiences gained during its first two years of operation. Early student reaction to this course of study has been favorable.

Introduction
Because all mankind is involved in a dynamic technological advance the comparison of which have never been seen before, nations that have been able to exploit their natural energy resources have made tremendous strides in raising their standard of living. In the United States the rate of advance is especially high where the rising affluence coupled with greater public demand for more and better products and services is transcending rapidly its citizens into a high energy-consumming civilization. The rest of the world is following closely behind our nation in this.
Since energy is required in order to do work, obviously the availability of large quantities of inexpensive energy and the efficiency of its conversion has been fundamental to increased productivity and economic progress.
Prediction of Hydrate Formation in Natural Gas Systems
Authors: Rossi L. F. S. , Gasparetto C. A. 
Published: December 2007

ABSTRACT
In this work a computational algorithm was developed to predict conditions of hydrate formation in natural gas systems, including the effect of inhibitors. The model utilizes Peng-Robinson equation of state and was developed with the objective of fast processing intended for quick results with simple field computing equipment or processor controllers. Development is based on van der Waals and Platteeuw [15] model wich accounts for the interactions between water molecules forming the crystal lattice and gas molecules. Description of such interactions utilizes the spherically symétrie potential of Kihara along with the contributions by Parrish and Prausnitz [10], John et alii [3], and Munckei alii [8]. From statistical and classical thermodynamics it is produced a reletionship between fraction of crystal lattice ocupation by the gas mixture and systems pressure and temperature. From this relationship is produced a curve indicating the region of viable hydrate formation.
Numerical Simulation of Pressure Transients in Naturally Fractured Reservoirs with Unsteady-State Matrix-to-Fracture Flow
Authors: Nanba T. 
Published: December 2007

ABSTRACT
Pressure transient behaviors in a naturally fractured reservoir with unsteady state matrix to fracture flow (transient interporosity flow) are simulated using a multiple interacting continua (MINC) method. The numerical method is verified by comparison with the analytical solutions.
In this paper, the pseudosteady state interporosity behavior in an actual field is explaind by using a concept of a matrix block skin. The behavior is also explained by introducing a concept that fractures contributing to interporosity flow are sparsely distributed in a reservoir. This new concept is numerically modeled by MINC method with a proximity function.
This paper also discusses the relationship between pressure transient behaviors and water imbibition performances.
Improved Formation Imaging with Extended Microelectrical Arrays
Authors: Safinya K. A. , Le Lan P. , Villegas M. , Cheung P. S. 
Published: December 2007

Abstract
Formation imaging using microelectrical arrays is an extremely powerful tool that enables the log analyst, geologist, geophysicist and petroleum engineer to better evaluate complex reservoirs. To date, electrical formation imaging tools with high spatial resolution can image only part of the borehole wall at any one time; attempts to increase borehole coverage have been achieved but with a small degradation of image resolution. A new formation imaging tool has been developed to provide real-time wellsite images of the borehole wall with unprecedented borehole coverage at a resolution of 0.2 in. The borehole coverage of this new tool is 80% in an 8-in. borehole, which represents an increase by a factor of two over previous generation tools. This increase has been achieved while also improving the spatial resolution of the tool. This paper describes the applications of the new tool and the improvement in interpretation of the images. Four tools have been built and tested successfully in wells throughout the world. Examples are given of a fractured formation, a reverse fault, a braided sand and a horizontal well to demonstrate the improvement in the data interpretation.
Multiple-Probe Formation Testing and Vertical Reservoir Continuity
Authors: Goode P. A. , Pop J. J. , Murphy W. F. 
Published: December 2007

Abstract
This paper introduces a strategy and methodology for the wireline measurement of permeability that is consistent with the geological structure observed at the wellbore. The strategy involves new technology; real-time data acquisition and interpretation in parallel utilizing high resolution borehole images and a multiprobe formation tester. The multiprobe tester differs from its single probe counterpart in that it has an additional two probes, displaced from the flowing probe, at which the pressure is monitored. In homogeneous formations this configuration permits the direct determination of both horizontal and vertical mobilities; in laminated formations such a tool allows the study of potential permeability barriers and their effect on vertical fluid movement. As part of the method, we introduce a new interpretation for the multiprobe tester based on flow regime identification using the pressures obtained at the observation probes.
Application of the method is demonstrated using data obtained from two field tests. In addition to electrical and nuclear logs, electric borehole images were obtained over the intervals of interest. The borehole images were used at the wellsite to identify several potential barriers to vertical flow and to choose the test points for the multiprobe formation tester. Subsequently these intervals were tested to determine the effect of the barriers on vertical communication. Additional multiprobe measurements were made in relatively unstratified zones to allow a comparison.
The results of one example indicate that features appearing as permeability barriers at the wellbore may not have large lateral extent and therefore do not act as barriers to vertical flow. The other example shows that the converse may also be true, in that, features which are observed to be thin at the wellbore can have considerable lateral extent and be significant barriers.
Outcrop Gamma Ray Logging: Truck-Mounted and Hand-Held Scintillometer Methods Are Useful for Exploration, Development, and Training Purposes
Authors: Jordan D. W. , Slatt R. M. , D’Agostino A. , Gillespie R. H. 
Published: December 2007

ABSTRACT
Reliable, reproducible gamma-ray logs of outcrops have been generated by two techniques with the objective of better visualizing interwell-scale lateral continuity (and discontinuity) of strata and to demonstrate reliability and potential pitfalls in subsurface wireline log correlations. One innovative technique was developed which uses a standard gamma-ray sonde run from a logging truck to log vertical cliff or quarry faces. The second technique employs a hand-held gamma-ray scintillometer to log more easily accessible outcrops.
Examples are presented from the Jackfork Group (Pennsylvanian), Arkansas of outcrop gamma-ray logging of both laterally continuous and discontinuous turbidites in structurally simple and complex settings. We have found that by using these examples, the following common wireline log correlation problems can be clearly explained to engineers and geoscientists, and understood, because the strata from which the logs were measured can be visualized and discussed at the outcrop: (1) the reliability of subsurface log correlations can be greatly improved by understanding expected subsurface depositional geometries and lateral fades changes, (2) wireline log correlations in strati-graphically and structurally complex settings, such as many oil or gas fields, may not be reliable without sufficient coring and special logging in addition to well testing, and (3) correlations and stratigraphic and reservoir quality interpretations of subsurface wireline logs in both oil/gas fields and in exploration areas can be improved by comparing the subsurface logs with outcrop gamma-ray logs of nearby analogous strata.
Flowline Storage Effect on Wireline Formation Tester
Authors: Yildiz T. , Desbrandes R. , Bassiouni Z. 
Published: December 2007

Abstract
The design of wireline formation testers (WFT) features a flowline full of drilling fluid. The compressible drilling mud in the flowline results in a "flowline storage effect" (FLSE) similar in nature to the well bore storage effect.
This paper presents a 3-D analytical model that includes the FLSE. The model is used to investigate the importance of this effect and its impact on pressure response. It shows that the response of the WFT is a combination of fluid decompression in the flowline and flow from the formation. Due to decompression of drilling mud in the flowline, the sandface flow rate is not constant and gradually increases from zero to the piston displacement rate. Slow pressure buildup observed in some field tests is partially due to the FLSE.
A laboratory experimental setup is used to investigate the effect of different parameters on the WFT response. Type curves based on the FLSE model are constructed and result in permeability values that are in good agreement with measured values.
A Case Study of Scaling Up 2D Geostatistical Models to a 3D Simulation Model
Authors: Harris D. E. , Perkins R. L. 
Published: December 2007

ABSTRACT
This paper reviews the procedure used in a recent simulation study in which results from two-dimensional (2D) cross-sectional geostatistical models were scaled up to a three-dimensional (3D) simulation model. Geostatistics (which included fractals) were used in the cross-sectional models to incorporate the effects of fine-scale heterogeneities in the coarsely-gridded, full-field model. Areal and vertical variograms were developed from well log data and used in the realizations. The geostatistical models were modified after the conditional simulations to preserve the integrity between each geostatistical model and the known geologic model. For this waterflood simulation study, the scale-up process involved matching the flood-front velocities and bypassed/trapped oil saturation values in the geostatistical models to those properties in the coarsely-gridded models. Although the scale-up procedure was specific to this reservoir study, the overall process can be modified for application in other studies.
Measurement of Velocity Profiles in Upwards Oil/Water Flow Using Ultrasonic Doppler Velocimetry
Authors: Morriss S. L. , Hill A. D. 
Published: December 2007

ABSTRACT
An experimental study used pulsed ultrasonic Doppler techniques to determine fluid velocities in two-phase oil-water vertical pipe flow.1 The data acquisition system was based on a medical ultrasound instrument, modified as needed, and a microcomputer. Measurements were made in a pipe with an inside diameter of 7.25 in. [18.4 cm], part of the Multiphase Flow Loop in the Department of Petroleum Engineering at The University of Texas at Austin. This pipe is 42 ft [12.8 m] long and can be inclined at any angle. The ultrasonic measurements gave reasonable qualitative results in all regimes of which the flow facility is capable: the Doppler frequency was generally proportional to the phase velocities. More theoretical and experimental work is needed, though, to improve the quantitative accuracy and to increase the measurement range: measured velocities were generally too low, and the range limit is estimated to be approximately 6 to 12 cm into the flow, depending on the regime. Backflow is measured on the low side when the pipe is inclined from the vertical.