bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Reservoir Simulation System for a Better Reservoir Management
Authors: Lefevre Didier , Pellissier Gérard , Sabathier J-C. 
Published: December 2007

ABSTRACT
Practically all the problems of reservoir development or reservoir management are analysed with a reservoir simulator. This tool must, consequently, be very versatile to allow to test very different hypothesis and very user friendly not to waste the engineer time. Indeed reliability, accuracy, performances are some of the basic requirements for an industrial tool.
Many simulators are presently available on the market. However, their range of applications is often limited and different "versions" have to be used to solve different problems. Differences between the versions (mainly due to different updatings and different programmings) may be detrimental to a sound appreciation of the discrepancies between two predictions made with two different versions. Consequently it was decided to create a new reservoir simulation system covering a very large range of possible applications and having a structure opened for new implementations. A key point is that, from the user's point of view, the model must not be more complex than required by the problem as far as input, documentation, memory requirements and performances are concerned. This is possible through a very efficient software management which is described in another paper[1]. Here we only describe some specific features of the general structure of the system, and of the geometry and well modelling aspects.
The Role of Simulators in Reservoir Management
Authors: Satter Abdus , Brugman R. J. , Yard M. B. , Mims D. S. 
Published: December 2007

ABSTRACT
A reservoir’s life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production, and finally to abandonment. Sound reservoir management is the key to successful operation of the reservoir throughout its entire life. The modern reservoir management process involves setting a goal and developing a plan, implementing and monitoring the plan, and evaluating the results.
Reservoir simulators play a key role in providing production and reserves forecasts needed in developing a reservoir management plan, monitoring, evaluating, and operating the reservoir. As opposed to only one reservoir life, the simulators can simulate many lives for the reservoir under different scenarios, and thus provide a very powerful tool to optimize reservoir operations.
This paper will discuss briefly reservoir management methodology and illustrate the role simulators can play in reservoir management with the following examples: Newly discovered offshore oil field: A black oil simulator was used to determine optimum recovery scheme, i.e., natural depletion or natural depletion augmented by water injection, and well spacing requiring the number of wells and platforms, reserves and economics. The simulation results were used to develop the optimum economic reservoir management program including development plan, and requirements to implement the plan, and to monitor and evaluate the project performance.Thermal recovery project: A thermal simulator was used to history match cyclic injection into a heavy oil reservoir. Based on the simulation study, wellbore damage and completion technique were identified as the cause for poor production response. A new well with an open hole gravel pack completion produced at a favorable rate.CO2 recovery project: A compositional simulator was used to history match performance of a primary depleted oil field followed by its performance prediction under CO2 flood. This study was made to optimize injection/production scheme including timing of blowdown and level of operating pressure.
Geochemical Study of Tar in the Uthmaniyah Reservoir
Authors: Tobey M. H. , Halpern H. I. , Cole G. A. , Lynn J. D. , Al-Dubaisi J. M. , Sese P. C. 
Published: December 2007

ABSTRACT
Tar is believed to be the main factor impeding production in certain regions of the Uthmaniyah area, Ghawar field. The effect of extraction with several solvents on the permeability and porosity of core plugs from tar zones in the Arab-D Formation was determined in order to understand to what extent tars contribute to obstructing the rock pores. Thin section examinations of the extracted rock were conducted to discern where the tar was distributed microscopically and how that distribution corresponded with the permeability and porosity data. The data show that in general, while organic matter continued to be removed by increasingly polar solvents, the effective permeability, which is controlled by the macropore system, showed little improvement. While the major pore network and macroporosity can generally be improved in the initial extraction, the marginally accessible porosity is still largely occluded by tar. Elemental and pyrolytic analyses of core samples before and after extraction indicate that the tar is neither itself homogeneous, nor uniformly distributed through an individual well, or from well to well. Some components of the tars are not soluble to any of the organic solvent systems utilized, and evidence that some of the tar may result from thermochemical sulfate reduction (TSR) is presented.
A Reservoir Characterization of a Naturally Fractured Reservoir: The Point Arguello Field, Offshore California
Authors: Buchwalter J. L. , Anderson D. M. , van Bloemen Waanders Bart , Genovese Paul 
Published: December 2007

ABSTRACT
A method has been developed to significantly improve the confidence in matrix block size and permeability determination fornumerical modeling of naturally fractured reservoirs.
The concept of fault bend folding from structure geology technology was used to divide the reservoir into areas of similar strain history, and hence fracture intensity. This technique was integrated with thewell test and conventional core data to obtain values for matrix permeability and block geometries areally acrossthe reservoirand vertically on a mechanical unit basis.
Numerical Simulation of Naturally Fractured Reservoirs
Authors: Fung L. S- K. 
Published: December 2007

ABSTRACT
The use of the dual-porosity approach for the modeling of naturally fractured reservoirs has become widely accepted in the oil industry. In this approach, it is assumed that the fissured porous media can be represented by two collocated continua called the matrix and the fracture. The original idealized model assumes that the fracture is the primary conduit for flow whereas the matrix acts as distributed sources and sinks. Since the introduction of this idealized model into the petroleum literature some 30 years ago, several improvements and/or refinements have been proposed. For example, the dual-permeability model was introduced when it became evident that for some fractured reservoirs, the continuity of the matrix is an important consideration. Much of the recent works on dual-porosity modeling are directed towards the more accurate representation of matrix-fracture transfers. In particular, the representation of gravity and capillary effects, capillary continuity or discontinuity of the matrix blocks, and the modeling of reimbibition phenomenon have received much attention.
Frequently, a fine-grid simulation (explicit discretization method) is used to evaluate the accuracy of a proposed transfer calculation. In such a simulation, the matrix blocks are discretized into several gridblocks. The adjacent fracture may also be discretized. The idea is that a fine-grid simulation can accurately represent the interplay of recovery mechanisms on the local scale and does not involve the assumptions of how matrix-fracture transfer ought to be calculated. However, in the field-scale simulation of these reservoirs, a fine-grid model is beyond the scope of today’s computer hardware capability. Therefore, some simplifications or lumping is required to keep the problem manageable. The paper will review several approaches documented in the recent petroleum literature, the approximations involved and their implications on the modeling of recovery processes in naturally fractured reservoirs. Based on the review, some suggestions are made as to the future development for this important area of reservoir simulation.
A Hostile Environment Gelled Polymer System for Well Treatment and Profile Control
Authors: Clampitt R. L. , Al-Rikabi H. M. , Dabbous M. K. 
Published: December 2007

ABSTRACT
Profile modification by crosslinked polymer treatments can significantly reduce water production and increase oil production in producing wells and improve the injectivity profiles and reservoir performance in injection wells. Profile modification has been successfully applied to cased-hole as well as openhole completions, long to very short pay sections, and naturally fractured and hydraulically fractured formations. Reservoirs treated include bottomwater drive, edgewater drive, waterfloods, reservoirs under gas injection, and for casing-leak squeezes. Polymer treatments are equally applicable to sandstones and carbonate reservoirs.
A stable polymer crosslinked gel system suitable for reservoirs in hostile environments (high temperature, high salinity with very high divalent cations) was developed for multiple well treatments for profile modification. The stability of the gel was tested in the lab under reservoir temperatures for long periods of time, and proven in several field pilot trials.
Two types of treatments were evaluated. In the first type, organic crosslinkers (gelation agents) were used, and in the second type, nonorganic crosslinkers were used. The organic system was superior because it was easy to implement and control during field operations as a result of the flexibility in gelling time which allowed injection of the required amount of the polymer deep in the formation; and secondly, because of the ability to inject slow-gelling-time gel as diverter for batch treatments in a multizone interval with thick gross thickness.
Rock-Compaction and Pressure-Transient Analysis with Pressure-Dependent Rock Properties
Authors: Kohlhaas C.A. , Miller F.G. 
Published: December 2007

Introduction
The equation generally used to describe unsteady-state fluid flow in porous media is the diffusivity equation porous media is the diffusivity equation either in terms of potential, head, pressure, or density. Terzaghi used pressure, or density. Terzaghi used the equation to describe changes of head within permeable layers of rock which resulted in fluid flow and rock compaction. Use of this equation to describe rock compaction requires the assumptions that permeability, porosity, formation compressibility coefficient, and formation thickness are constants. It is also assumed that grain volume is constant and that bulk-volume reduction equals pore-volume reduction.
Terzaghi's results have been applied to many engineering problems, including the compaction of oil-reservoir rocks due to fluid-pressure decreases caused by fluid withdrawals. For a horizontal, isotropic, homogeneous layer bounded on the top by an impermeable boundary and on the bottom by a high-permeability layer which acts as a drainage channel and in which there is a sudden drop of head from hi to ho at t = o Terzaghi gives the head as a function of time and distance:
(1)
Overburden loads are supported by a combination of the rock grain-to-grain "pressure", PG and the interstitial fluid pressure, Pf:
(2)
Compaction of the rock is a function of changes of PG, which is often designated "compaction pressure." From equation (2) therefore, it may be seen that rock compaction, designated "shrinkage" by Terzaghi, is a function of Pf if Pob is constant.
Multiwell Application of Downhole Temperature Profiles for Crossflow Analysis
Authors: Petricola M. F. J. , Watfa Mohamed 
Published: December 2007

ABSTRACT
Temperature profiles have been used extensively for problem diagnostics related to downhole leaks and cross-flows behind the casing. The classical procedure is to obtain a true geothermal temperature profile and correlate future temperature changes to the geothermal to obtain an estimate of the location, magnitude and direction cf the cross-flow anomalies. This single well technique was limited by the availability of a representative geothermal gradient, local and time-lapse variations in this geothermal gradient, coupled with the absolute accuracy required from the temperature readings.
The technique presented in this paper looks at extending the single well temperature profile analysis to multi-well data-base application. Here the temperature profiles for a selected number of wells in a field are loaded in a database. The geothermal variations across the field can then be quantified at any given period of time from the median reading for the wells in that area. This allows for data normalizations for all the wells, which improved the accuracy of the temperature readings. The net effect is an order of magnitude improvement in accuracy, which facilitated the detection of small leaks and cross-flow of fluids behind the casing. In essence, this technique overcomes all the shortcomings and errors that are normally associated with the single well temperature profile evaluation.
The examples presented show the classical applications of temperature profile evaluation in a variety of behind the casing cross-flow environment. The results also show how a geothermal gradient can be obtained from a family of wells where no representative geothermal gradient is available over the intervals of interest. The resultant improvement in resolution also highlight the presence of very slow leaks, that would otherwise have not been detected.
Polymer-Augmented Waterflooding in a Reservoir With a Bottomwater Zone
Authors: Hodaie Homayoun , Bag~ci A. S. 
Published: December 2007

ABSTRACT
In this paper the effect of preselected polymers on waterflooding of a limestone reservoir with or without bottom water zone, as well as the effect of vertical and horizontal production wells on oil recovery have been investigated in laboratory models. Sixteen core flood displacement tests were conducted to study the effect of relative oil-water layer thickness, slug size and well configuration in production port. A quantitative comparison was made to show the difference between waterflooding and polymer augmented waterflooding runs, where a light crade oil with a viscosity of 14.5 mPa.s was used.
Among six polyacrylamide samples of different ionic characteristics and molecular weights, the polymer with low ionic and medium molecular weight characteristics showed the best resistance and residual resistance factor behaviors during eight polymer flood tests and was selected for displacemet tests.
The results of the displacements tests showed that as the thickness of bottom water zone increases, the ultimate oil recovery decreases. Polymer solution had a favorable impact on the waterflood performance. However, the worse the conventional waterflood performance was, the more effective the polymer as mobility control agent. For polymer injection, the effect of slug size was discussed with the aid of concentration curves and retention rate values, and a slug of 0.6 PV was obtained as optimal. Using horizontal production well showed slightly better oil recovery than vertical production well in conventional waterflood of the reservoir model with a thin bottom water zone. However, in polymer augmented waterflooding oil recovery was less than that in vertical production well case. This was due to the early production of polymer solution and reduction of the swept area by polymer which was investigated by concentration curves as well.
Applications of VSP Inversion in Reservoir Characterization
Authors: Ahmed Shabbir 
Published: December 2007

ABSTRACT
Improvements in downhole seismic data acquisition and processing techniques now make it possible to extract a high resolution formational impedance log at the well, from the VSP traces. The redundant information from VSP upgoing wavefield helps to enhance the signal-to-noise ratio and to restore true high frequency impedance information, through Entropy Minimization technique. The extracted acoustic impedance profile at the well is further used to invert the surface seismic traces, away from the well. The resulting acoustic impedance data not only shows accurately the stratigraphic variations of the subsurface away from the borehole, but also helps to characterize the key reservoir formations.
The Integration of Seismic and Well Data for Improved Reservoir Models
Authors: King G. A. , Archer S. H. , Seymour R. H. 
Published: December 2007

ABSTRACT
The contribution that seismic data can make to the structural and stratigraphic model of a reservoir is well known, as is its ability to delineate fluid contacts in favorable circumstances. However, lithologic control in reservoir simulation models frequently are limited to information gathered at wells. Any advance in interwell correlation will strengthen the validity of the models. A practical constrained inversion technique is presented by which a seismic survey can be used to improve the estimates of lithology and porosity in undrilled areas of a reservoir on a scale appropriate for reservoir simulation modeling.
The input data for the constrained inversion technique are acoustic logs estimated from the wide band combination of borehole logs, seismic and geological data. The basis of the inversion method is to distribute conventionally interpreted borehole estimates of lithology and porosity throughout a field, guided by the existing seismic-geologic interpretation of the field's structure and stratigraphy. Selected petrophysical relationships and constraints are invoked in an iterative inverse procedure to perturb the lithologic and porosity models by the least amount necessary to explain the detailed seismic reflection amplitude data. The final result is a highly resolved lithologic and porosity model of the field, consistent with all available borehole, geologic and seismic data, suitable for use in field evaluation and for building reservoir simulation models. Also, these detailed estimates may be calibrated with core data to provide useful information about the permeability variation throughout the field. The technique is illustrated with a field data example from a three dimensional seismic prospect where complex reservoirs are present.
Description and Interpretation of North Sea Fractured Chalk Formations
Authors: Meling L. M. , Lehne K. A. 
Published: December 2007

ABSTRACT
This paper describes novel methods for fracture description and implications by using well logs, core data, well tests and geological inteipretation.
The type, amount and orientation of fractures and fracture systems have major impact on field behaviour. We present methods to estimate in situ stress and fractures from logs. Fracture description from cores further enhance the proposed description of the fracture system. The paper also show how well test data give quantitative informations about fracture conductivity initially and during field depletion.
If fracture conductivity exceeds a fracture intensity threshold, separate matrix blocks occur. We identified such systems by a new method which identify individual capillary pressure systems and thereby individual matrix blocks. We also used the method to identify in situ wettability.
The methods presented in this paper we successfully used for some North Sea Chalk fields.
Application of Anti-Whirl PDC Bits Gains Momentum
Authors: Sinor L. A. , Warren T. M. 
Published: December 2007

Abstract
Over the past four years the phenomenon of bit whirl has been identified as a maj or cause of premature failure and reduced performance of PDC bits. Examples of the successful application of commercially available Anti-Whirl bits for straight hole rotary drilling, straight hole motor drilling and steerable directional drilling are presented. Also discussed are a number of features that may be used either separately or in conjunction with the Anti-Whirl design to help reduce the tendency to whirl.
A Systems Approach to Drilling Fluids Management Improves Drilling Efficiency: A Case Study on the NN Platform in the Arabian Gulf
Authors: Moore D. J. , Forbes D. M. , Spring C. R. 
Published: December 2007

ABSTRACT
The NN - platform was drilled offshore Dubai in the SW Fateh field by Dubai Petroleum Company. As a total of 16 wells were drilled, a sharp learning curve was required to optimize drilling efficiency. Each well was drilled to a depth of +/- 10,000 ft using a gel based mud in top hole, with two thirds of the wells being completed to total depth (TD) utilizing a KCL polymer system and the remainder of the wells using a low toxic oil based mud (LTOBM) system. This paper focuses primarily on a systems approach to drilling fluids management and tries to establish the degree to which this affects drilling efficiency. Sharp learning curves were established through increased monitoring of the fluid and by integrating solids control efficiency with normal mud engineering practices. Particular attention to the cost per foot,mud usage, drilling time, and hole quality was used to determine drilling fluid performance. Any major changes in other drilling parameters (such as hydraulics or bit type) arereported. Since the monitoring of drillingfluids has not changed significantly in recenttimes, the question must be asked "how can sharper learning curves be establishedfor the future?". Hence, the second part of this paper will deal with future improvements regarding fluids monitoring at the rig site and what effects this might have ondrilling efficiency. Attention will be givento the data processing aspects and interpretation. Correlations to particular instances on the NN platform will be used as examples to illustrate the need for such measurementsand the value they will have on future drilling operations.