bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computers And Graphic Display Systems A New Technique For The Petroleum Scientist
Authors: Lowe Howard R. , Ross J. Alan 
Published: December 2007

Abstract
Recent developments in the computer field will soon make it possible for a geologist or engineer to have on-line capability for many complex geological and engineering problems. New computer peripheral equipment includes many different types of graphic display systems. Technical personnel will have unprecedented conversational capability to work with visual graphics data. They can refer to data, change data, initiate new ideas, compare data all within the framework of a defined problem. problem. Now one can perform complex activities such as preparation of contour maps, decline curves, three dimensional representations, stereoscopic or mathematical models in seconds instead of weeks or months. The conversational mode of operation of such units allows the operator complete control of the desired display. Objects can be moved about, using a light pen to detect a particular line segment or symbol. The keyboard allows one to change parameters or add new information. The time parameters or add new information. The time required to solve a problem is cut dramatically. The ability of the technician to change points on a three dimensional basis will be points on a three dimensional basis will be of great value in the fields of exploration, exploitation, and reservoir engineering. Visual display can be obtained along any desired axis or on any scale or projection. Utilization of sophisticated data information systems in conjunction with graphic display systems will undoubtedly revolutionize techniques now In use in the petroleum industry. The speed and versatility which these systems will make possible will create a far greater impact on the industry than anything ever experienced in the past.

Introduction
The application of high speed computers to exploration and exploitation problems is a relatively new technique. Less than five years ago the geologist and engineer found it necessary to spend hours, days, or weeks accumulating and preparing data to eventually make a study. Petroleum technology has advanced by leaps and bounds since the late 1940's: with these advances came a staggering amount of data and information. The advances in technology were actually restricted because of the impossibility of handling vast quantities of scientific data and information.
The increase in exploration and drilling costs has made it necessary to look for techniques outside the petroleum industry to solve these many problems, and thereby cut costs. Decision making, both on the technical as well as management level, requires a much faster means of handling, correlating and interpreting scientific data. No industry collects more varied and voluminous information and data than the petroleum industry.

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Best available copy - damaged original.
A Case Study of the Full-Field Simulation of a Reservoir Containing Bottomwater
Authors: King G. R. , Snyder D. E. , Obut T. S. , Perkins R. L. 
Published: December 2007

ABSTRACT
A recent simulation study was conducted on a reservoir which was completely underlain by bottom-water. Thirteen wells, eleven production wells and two injection wells, were considered in the study. Due to the high vertical permeability (approximately one Darcy) and lack of correlatable shales, the production wells were expected7 to exhibit critical coning rates of approximately 150 BFPD (calculated). To economically justify the project, production rates of 3000 – 5000 BFPD per well were required. Consequently, early water production problems were expected from the reservoir. This paper discusses the methods used in the reservoir simulation study to assess the impact of water production on the project. The simulation study discussed in this paper was comprised of both single-well and full-field simulation models. The objectives of the single-well modeling were to gain insight into the individual well behavior and to calibrate the full-field models by use of well pseudofunctions.
For vertical producers in the full-field models, two approaches were used: the traditional pseudo-function approach and the hybrid-grid approach. In the pseudofunction approach, both vertical equilibrium (VE) well pseudo-functions and dynamic well pseudo-functions were considered. Due to CPU time constraints, the hybrid-grid approach was principally used to validate the pseudo-functions and to "fine tune" key prediction cases.
To alleviate coning problems, horizontal production wells were also considered in the full-field model. For these wells, only dynamic well pseudo-functions were considered. These pseudo-functions were generated using finely gridded single-well models and used in the full-field model to describe well behavior.
Since this paper addresses several current topics in reservoir simulation, such as the use of hybrid grids and the modeling of horizontal wells (along with the scaling of these technologies from the single-well, conceptual scale to the full-field scale), we believe that the material presented in this paper will provide a framework for future simulation studies of bottom-water reservoirs.
Rigorous Black Oil Pseudo Functions
Authors: Stone H. L. 
Published: December 2007

ABSTRACT
A new method of calculating black oil pseudo functions from a fine grid simulation of a reservoir is given. These functions when used in a coarse grid simulation of the same reservoir will reproduce the accuracy of the original fine grid simulation. This accuracy results for any production rate even when used to coalesce non-communicating layers from the fine grid model into a single coarse grid layer. All previously published methods are accurate only for low viscous-gravity ratios, which correspond to a combination of a low production rate and good vertical communication between layers in the reservoir.
Compositional Reservoir Simulation in Parallel Supercomputing Environments
Authors: Briens F. J. L. , Wu C. H. , Gazdag J. , Wang H. H. 
Published: December 2007

Abstract
This paper presents the important considerations, programming and computational techniques for the development of a fully parallel and vectorized compositional reservoir simulator. A modified Young formulation is used for the flash calculations and a novel algorithm called Sequential Staging of Tasks (SST) that can take full advantage of parallel vector processing to speed up the solution of a large linear system is introduced. Compared to domain decomposition, SST has a number of noteworthy advantages illustrated with the results of computer experiments conducted on a parallel supercomputer with 6 vector processors. Memory-efficient techniques for out-of-core simulations are also discussed. The simulator developed with the techniques presented in this paper can handle compositional reservoir simulations as large as 200,000 grid blocks and components with reasonable turn-around times and can provide a 100 times speed-up over conventional serial computers.
Modeling the Performance of Horizontal Injection Wells in Carbon Dioxide Miscible Displacement Processes
Authors: Ammer J. R. , Enick R. M. , Klara S. M. 
Published: December 2007

ABSTRACT
A black-oil, pseudo-miscible simulator, a compositional simulator, and a compositional/ incomplete mixing simulator were used to model first-contact miscible!, carbon dioxide, enhanced-oil recovery experiments. The experiments were conducted by the University of Wyoming in a three-dimensional, high-pressure, physical model to investigate the effect of injection well geometry on oil recovery. These laboratory scale experiments showed that oil recovery could be significantly increased using a horizontal injection well instead of a vertical injection well. The objectives of this study were to evaluate the capability of each simulator to accurately model these displacements and to use the most appropriate simulator to investigate the mechanisms that led to improved oil recovery.
Both the black-oil, pseudo-miscible simulator and the compositional simulator were unable to provide a match of the experimental results. The pseudo-miscible simulator overpredicted the recovery rate and the ultimate recovery of oil because it could not accurately account for the large volume change when mixing carbon dioxide and heptane (laboratory oil). Only limited success in providing better matches was attained when the effects of viscous fingering were incorporated by lowering the value of the mixing parameter. The overproduction of oil resulting from the poor phase behavior description was too large to be compensated for by altering the mixing parameter. The compositional simulator provided a more realistic description of the phase behavior and, therefore, yielded good matches of oil production before breakthrough. However, the recovery of oil after breakthrough was overpredicted. It was not possible to improve these simulation results by accounting for viscous-fingering effects since the compositional simulator assumes complete mixing in all grid blocks.
A compositional/incomplete mixing simulator that empirically accounted for the macroscopic effects of viscous fingering by assuming incomplete mixing within grid blocks was then employed. An additional parameter was required to define the rate of mass transfer of oil from the ‘bypassed’ phase of a gridblock into the oil phase where mixing with the carbon dioxide was allowed to occur. A high value of the parameter (100 or more) corresponded to no viscous fingering as commonly assumed in conventional simulators, while a low value corresponded to the maximum degree of fingering effects. Good matches between simulation and experimental results for both the vertical and horizontal injection schemes were obtained using this model with parameter values of 0.1 and 2.5, respectively. These results indicated that viscous fingering probably occurred in all experiments, with the effect being much less pronounced when the horizontal injector was used.
Stability-Based Switching Criterion for Adaptive-Implicit Compositional Reservoir Simulation
Authors: Grabenstetter J. , Li Y.-K. , Collins D. A. , Nghiem L. X. 
Published: December 2007

ABSTRACT
A stability criterion for determining the degree of implicitness in adaptive-implicit compositional reservoir simulation is derived and discussed. The criterion is based on the Courant-Friedrichs-Lewy (CFL) condition for the stability of explicit discretizations of hyperbolic systems of partial differential equations. The criterion can be computed using quantities either directly available from the Jacobian-building sections of the compositional simulator, or obtainable through minor modifications to the simulator. The criterion can be used for switching both from explicit to implicit and from implicit to explicit discretizations of a block. Several strategies for applying the criterion to determine an appropriate degree of implicitness in practical reservoir simulations are proposed and tested.
Heterogeneous Reservoir Models: Local Refinement and Effective Parameters
Authors: Espedal M. S. , Langlo P. , Saevareid O. , Gislefoss E. , Hansen R. 
Published: December 2007

Abstract
Heterogeneous porous media are generally characterized by many scales of variations. A methodology is required for transporting information from one scale to another. Also, grid refinement techniques require that we are able to assign effective permeabilities on grid-blocks of different sizes. Recently, methods for calculating effective permeabilities on blocks of arbitrary size have been developed for models in groundwater-flow. We have extended these methods to a two-phase model, where a new dispersion coefficient is derived.
Based on operator-splitting techniques and adaptive grid-refinement, we have developed a discretization strategy able to resolve local phenomena in space and time. The solution procedure includes the concept of domain decomposition where the global solution is constructed from local computations on sub-domains. This approach allows the resolution and even the entire solution strategy to depend on local properties of the model. The algorithm is well suited for parallel computer architectures as well as integration into existing large scale simulators.
In the present paper these techniques are tested for heterogeneous, two-dimensional two-phase models. Numerical experiments based on fine-scale discretization are compared with the results from the calculation based on averaged equations.
Simulation of the North Brae Gas Condensate Reservoir Development
Authors: O'Byrne D. K. , Sadighi S. , Lane G. L. 
Published: December 2007

ABSTRACT
The North Brae Field is the first offshore gas condensate reservoir in the North Sea to be developed with gas injection for pressure maintenance. The field has been on production since April 1988 and produces wet gas at a plateau rate of 440 MMSCF/D with liquid rates averaging 80 MSTB/D during the first half of 1990. Processed dry gas is currently injected to the reservoir, along with some makeup gas from the South Brae platform at rates of about 400 MMSCF/D. It is intended to continue with gas cycling until 1993 at which time the produced gas will be exported from the platform.
This paper reviews the development of the field over the first two years of producing life. Emphasis is placed on reservoir description and simulation of performance. In particular, results of a model match to compositional field data are reported for this North Sea reservoir.
Simplified Equations for Planning Directional and Horizontal Wells
Authors: Wiggins M. L. , Juvkam-Wold H. C. 
Published: December 2007

ABSTRACT
Directional drilling techniques have been used for many years to reach subsurface objectives that have had inaccessible surface locations. Economic considerations and increased environmental concerns have increased the number of directional wells drilled in recent years. Directional drilling techniques have also been applied to horizontal drilling with interest in this area increasing greatly over the last several years.
In the past, there have been two major methods utilized in planning the directional well. These methods are the use of buildup or composite buildup charts and the use of several directional well planning equations, each method depending on the particular wellbore geometry desired. The use of buildup charts is a tedious process that often yields inaccurate results since it requires using preplotted graphs that require interpretation and interpolation. The equation approach is often confusing to use due to the similarity of the various equations with the selection of the proper equation dependent on the desired wellbore geometry.
This paper presents the derivation of a single equation for planning the trajectory of any directional well and a similar equation for any horizontal well. Several examples are used to demonstrate the application of the equations to various wellbore geometries.
Air Drilling and Multiple Hydraulic Fracturing of a 72° Slant Well in Devonian Shale
Authors: Yost A. B. , Carden R. , Muncey J. G. , Stover W. E. , Scheper R. J. 
Published: December 2007

ABSTRACT
This paper discusses site selection, air directional drilling, stimulations, and economic evaluation for a 72° slant well drilled in the Devonian shale, Roane County, West Virginia. The well was drilled to evaluate the concept of using directional drilling and multiple hydraulic fracturing to improve the gas production from a 450-foot naturally fractured Devonian shale section. The well trajectory remained in target for more than 1,500 feet at a preferred azimuthal direction perpendicular to the regional fracture trend and also the known production fairway.
The well was conventionally drilled to the kickoff point of 2,150 feet. Afterwards, positive displacement downhole motors were used to build hole angle up to a 72° hole angle at the top of the target zone. Once the target zone was reached at 67°, conventional rotary assemblies were used to rotate the well across a 1,500-foot target section in which inclination varied from 67° to 72° of hole angle. After reaching total depth of 4,833 feet, the well was logged using wireline and drill pipe conveyed methods. Then 5 1/2-inch casing was run and cemented with 60 rigid centralizers to improve zonal isolation.
Four stimulations were designed and completed. All stimulations will be discussed in the paper. Economic analysis was conducted to show expected improvements from the application of this technology to fractured Devonian shale. Post-stimulation well testing has been identified for each zone to show initial results.
Semilog Type Curve for Interpretation of Well Test Data
Authors: Aminian K. , Ameri S. , Gaines T. E. , Morris M. E. 
Published: December 2007

ABSTRACT
One of the most common, economical and reliable sources of information to determine the commercial productivity, the formation characteristics, and well conditions is the pressure transient test. However, the pressure transient test must be properly designed, run, and interpreted to provide the desired information.
The pressure transient data are usually interpreted by plotting the pressure versus time on semi-log paper. The semi-log interpretation method is often impractical due to difficulties associated with identification of the correct straight line. Type curves provide a more general method of interpretation. In this method, a plot of pressure versus time on a log-log paper is utilized to obtain a graphical match (solution) with the type curve. The log-log plots, however, then to minimize the differences in the shape of the various type curves. Therefore, a unique solution is often difficult to obtain, especially when the well test is short.
This paper introduces a methodology for interpreting well test data by utilizing more sensitive semi-log type curves. The semi-log type curves are useful for verifying the uniqueness of the solution. The methodology has been explained and discussed through several examples utilizing published well test data.
Evaluation of a Cleanout Procedure for Increasing Production From Old, Natural, Openhole Devonian Shale Wells
Authors: Hopkins C. W. , Gatens J. M. , Wallace J. L. , Ahmad M. M. , Reeves J. S. 
Published: December 2007

ABSTRACT
This paper summarizes the results of a cleanout study performed on six Devonian Shale wells in southwestern West Virginia. This study was part of a joint Columbia Gas System Service Corporation (CGSSC), Columbia Natural Resources (CNR), and Gas Research Institute (GRI) project which involved 'cleaning out' shale rock debris from several old, natural, openhole Devonian Shale wells for the purpose of evaluating Devonian Shale production mechanisms. Based on well test analysis and four years of production data, it appears the cleanout procedure is economically attractive for increasing production from these types of wells.
Six wells in Mingo, Wayne, and Logan Counties, WV were selected as candidates for study. Using a cable tool rig, Columbia found the Devonian Shale openhole sections in these wells filled up and bridged off with shale rock debris. The debris was removed with a bailer, but some tool sticking problems were encountered. Post-cleanout rates increased as much as six-fold over precleanout rates as a result of these operations (73 to 411 Mscf/D for one well). Pre- and post-cleanout well test analyses performed on three wells indicated the cleanout operations resulted in increases in completion efficiency (more negative skin factors), permeability-thickness products, or both for each well. Analysis of four years of post-cleanout production data has shown the initial post-cleanout flow rates have been sustained, and it appears the cleanout operations have increased the ultimate recoveries for these wells.
Based on these initial results, CNR performed a pilot cleanout project in 1989 on four wells using a rotary rig for the cleanout operations. Many problems encountered using the cable tool rigs were avoided with the new procedure. Initial results have been encouraging.
Our analysis indicates a cleanout operation, on average, could increase estimated recovery by 210 MMscf over a 20-yr period. Assuming typical operating economic data, this increase in recovery could translate to a net present value of $197,000 per well. If 10% of the over 15,000 Devonian Shale wells in the basin were candidates for cleanout, this workover operation could translate to an increase in reserves of 315 Bscf with an associated net present value of $296 million.
Determination of the Drillability of High-Angle, Large-Displacement Wells by Analyzing the Effects of Dog-Leg Severity
Authors: Navarro A. R. , Yalcin O. 
Published: December 2007

Abstract
Directional wells are playing a larger role in today's drilling industry. With the development of steerable drilling systems, high angle, large displacement wells have become commonplace. The planning of these more complex well paths has created a need for an empirical analysis using previously drilled directional well data to determine the mechanical feasibility of drilling these wells when considering torque and drag, "drillability".
Data from wells drilled on South Pass Block 60 G-Platform in the Gulf of Mexico has been analyzed to develop an empirical method which will accurately predict torque and drag when planning future high angle, large displacement wells. Torque and drag prediction methods previously published (1,2), were based on the determination of the actual friction coefficient from field data. This has been accomplished by either utilizing a computer model and varying the friction coefficient until a match between calculated and measured surface torque values has been obtained or by utilizing MWD-downhole and surface weight-on-bit and torque measurements and calculating the friction coefficient on a foot-by-foot basis. These friction coefficients generally result in much lower torque and drag predictions for planned wells than are actually measured on drilled wells. These lower values may be attributed to the neglect of the effect of dog-leg severities which are introduced in the normal course of drilling or during correction runs. Previous work (3,4) used a survey simulator based on a random number generator, where dog-leg severities were controlled by an arbitrary scale factor which is called a "dog-leg severity factor".
This paper describes a more accurate method of predicting torque and drag by incorporating the effects of dog-leg severities from a survey database into an existing torque and drag simulator, for the design of the ideal well plan.
A Case History of Trempealeau Completions in South Central Ohio
Authors: Cramer J. W. 
Published: December 2007

ABSTRACT
Wells drilled into the Trempealeau formation in south central Ohio require adherence to special plans and attention to detail at the price of economic success. This formation is marked by nonconformance, paraffin production, delicate oil-water contact, and a susceptibility to drilling-induced damage.
This paper provides guidelines for completion practices that have been based on 30 years of drilling in the Trempealeau formation and presents typical job designs.
New Applications of Flow Controllers for Some Field Production Problems
Authors: Weiant W. S. 
Published: December 2007

ABSTRACT
This paper describes the use of flow controllers ahead of orifice meters on well locations and master stations. The controller has taken a typical production chart that was very difficult to read and made it much more accurate to integrate.
Further, the application of flow controllers at the separator as a "throttling choke" has shown numerous benefits. The elimination of choke freeze-off and improved fluid flow on combination gas/oil wells has been very successful.