bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling Heterogeneity To Improve 3-D Simulation Results: A Case History on a North Sea Gas Field
Authors: Haak A. M. , Elewaut E. F. M. 
Published: December 2007

ABSTRACT
A 3-D simulation model of a Rotliegend gas field was made to describe the fluid behavior in the reservoir under strong water drive. The model was supported by a detailed geological model giving the lateral distribution of the porosity, horizontal permeability and the flow characteristics of the reservoir rock. The vertical effective permeability was coupled to the horizontal permeability by means of a statistical probability technique.
The model was matched satisfactorily with the decline of the average field pressure and with the detectable water movement in the field (including water breakthrough in one of the producing wells). The adjustments to the matching parameters were endorsed by the geological research. The geological model thus provided a base for an adequate and relatively simple modeling procedure.
The simulation model indicates that the gas-water contact in major parts of the field is at present located at a higher level than is supported by field observations. The presence of fluviatile shaly members plays an important role in the water movement in the field. It is believed that field observations on the water movement may to some extent be masked by the presence of major shale breaks in the eolian units in the vicinity of the wells.
The simulation model was used successfully to predict fluid movement in the reservoir.
Velocity of Sound Correction of Vibrating Element Density Transducers.
Authors: Norvik H. A. , Tambo M. 
Published: December 2007

ABSTRACT
A mathematical model for ‘vibrating element’ density transducers is derived. The origin and magnitude of reading errors inherent in this type of instrument is analysed. The theory is substantiated by newly acquired experimental data, covering a wide range of pipeline operating conditions up to 150 bar. The model is believed to be suitable for correction of density meters in field applications. The treatment specifically deals with ‘cylindrical membrane’ transducers, but the qualitative findings are believed quite generally applicable.
Iron Sulfide Scaling and Associated Corrosion in Saudi Arabian Khuff Gas Wells
Authors: Kasnick M. A. , Engen R. J. 
Published: December 2007

ABSTRACT
Khuff reservoir gas wells have been produced for 5 years in Saudi Arabia. These wells are classified as sour gas producers with hydrogen sulfide and carbon dioxide contents of four to five mole percent each. The production contains 1.5 to 2 barrels water per million standard cubic feet of gas with a moderate (30–50 barrels per million standard cubic feet of gas) amount of heavy condensate.
Scales with iron sulfides as the major components form in nearly every producing well. These scales have minor compositional variations but form at differing rates and thicknesses in the lower half of the L-80 tubing string. Tubing has been recovered with scale deposits from several wells. Intense analysis of the scale, the underlying corrosion, and the metal pipe have revealed information about scale formation in these wells. Although the investigation continues, several conclusions regarding the causes of scale formation, the effects of completion practices, and recommendations for mitigation are discussed.
Quantitative Evaluation of Highly Laminated, Complex Lithology Formations
Authors: Andreani M. 
Published: December 2007

Abstract
Thinly bedded and laminated shale-sand-carbonate formations exist in most of the producing formations in Egypt (a thin bed is defined as having a thickness of the order of two inches). Over certain sections of the field considered in this paper, such formations make up the bulk of the reservoir, and conventional interpretation techniques could mask the true nature of the formation, resulting in an erroneous evaluation and the possible risk of missing the reservoir completely. This paper outlines an interpretation technique which has been developed to evaluate the thin producing zones and their contribution to a formation's producibility. With this information it is possible to know, with accuracy, the size of the reservoirs, where to perforate, and the test intervals to consider.
Both the attenuation (Eatt) and the transit time (Tpl) of the Electromagnetic Propagation Tool (EPT*) are used to evaluate the laminated shale and lithology distribution. The attenuation is calibrated to provide a direct and quantitative shale content value with excellent vertical resolution and pass-to-pass repeatibility with the sonic transit time and neutron porosity (ΔT - øN) shale indicator, which is an established reference in this environment. The Tpl measurement, after compensating for the shale volume, is used effectively to differentiate the matrix lithology. This gives calibrated thin bed shale and lithology transforms, which are combined with conventional logs to evaluate the porosity and saturation values. The computed water saturation in the invaded zone is used to obtain high resolution permeability and producibility for all the layers. The results are compared with well test and high resolution dipmeter data. It is found that the producibility data, predicted by this technique, matches the flowmeter data. This technique is used successfully to identify transition zones in laminated beds. In addition, the recoverable volume of reserves in shaley, laminated reservoirs, is often found to be much higher than previously expected.
A Simulator for the Recovery of Heavy Oil From Naturally Fractured Reservoirs Using Cyclic Steam Injection
Authors: Briggs P. J. 
Published: December 2007

ABSTRACT
This paper describes a simulator which has been developed for the specialised application of predicting the performance of cyclic steam injection, when used to recover heavy oil contained in naturally fractured reservoirs. The potential application of the simulator will be for evaluating fractured carbonate reservoirs, which contain a large proportion of the known heavy oil resources.
The reservoir is divided into a rock matrix/fracture system with the rock matrix assumed to be described by a number of cubic blocks surrounded by interconnecting fractures. The flow of injected steam and its condensate is limited to the fractures and heat transfer to the rock matrix is only by conduction. The temperature of the matrix blocks and the heat lost to the overburden/underburden are obtained using an approximate analytical solution to the heat diffusivity equation. The simulator then predicts the rate of interchange of fluids from rock matrix to the fractures by the processes of thermal expansion and countercurrent imbibition. Production rates of oil and water from the thermally stimulated well are calculated, based on a PI which is adjusted to account for the temperature dependent fluid viscosities and the fluid heights in the fractures. During the production period, the heat loss to the overburden/underburden and the produced fluids is calculated at each time step.
Results from the model show the advantage of a fracture system in conducting heat into the rock matrix, because of the large surface area exposed to heating. The simulator can be used to investigate the interaction between various reservoir and input parameters in an attempt to devise the best reservoir management strategies. Initial results show the importance of steam slug size, steam injection rate, steam temperature and applied drawdown in attaining the best economic operating conditions. The matrix block size and permeability were found to be the most important of the reservoir variables changed in the sensitivity analysis.
History Match and Future Production Strategy of a Multi-Reservoir Field
Authors: Sheshodia T. S. , Mubarak S. I. , Javed M. S. , Rahman B. A. 
Published: December 2007

ABSTRACT
The paper briefly describes the reservoir simulation model, history match, fluid migration and future production strategies of a multi-reservoir oilfield in Kuwait. The reservoirs have production history of forty years and about 28 percent of in-place oil have been recovered. Edge-cum-bottom active water drive from an extensive aquifer has helped to maintain the reservoir pressure in major parts of the field. Water intrusion has taken place in some wells due to bottom water coning and in few others due to water fingering.
Variation in lateral as well as vertical fluid migration with production changes is found interesting. The increase in quantum of water cut production with time has been predicted to facilitate timely planning for proper design of produced water disposal. Infill wells have been recommended for proper drainage and for enhancing the production potential of the field for a longer period.
Tests of ASR, DSCA, and Core Discing Analyses To Evaluate In-Situ Stresses
Authors: Perreau P. J. , Heugas O. , Santarelli F. J. 
Published: December 2007

Abstract
The vertical distribution of the minimum horizontal in-situ stress is the major parameter which controls the confinement height and direction of hydraulic fractures. The minifrac technique has been extensively used to collect these data. However, its implementation in the payzone and adjacent layers is often hindered by technical and economic considerations. Consequently, the determination of the stress field on the basis of laboratory measurements in orientated core samples has been investigated. New developments and the results of three methods are described: anelastic strain recovery (ASR), differential strain curve analysis (DSCA), core discking analysis. The results obtained using these methods on cores extracted from several wells are described and discussed. A comparison is made with data available from minifracs, logs and regional tectonics. The main conclusions are that different methods give a good idea of the principal horizontal stress.
Operation of a Second Steam Stimulation Pilot Project in Kuwait
Authors: Ahmad K. N. , Milhem M. M. 
Published: December 2007

Abstract
Two pilot steam stimulation projects were initiated to study the feasibility of application of steam for recovery of heavy oil occuring in a shallow depth reservoir in Kuwait.
The first pilot cyclic steam stimulation project was started in September 1982 with 4 wells1. This is still in the first production cycle with an overall OSR of 10.316 till end September 1988.
The second pilot cyclic steam stimulation project was commissioned in June 1986 and steam injection to the first well commenced on 25th June 1986. Injection continued from well to well and terminated in the 4th well on 23rd August 1986.
The salient features of this pilot are: 1)Use of treated brackish water produced from a shallow water well.2)Facility to switch steam from one well to another without interruption of operation by using combination steam and oil header.3)Compared to the first pilot a very short natural flowing life of the wells.4)Long distance pumping of the crude oil without any additive or pipeline heating.
These 4 wells are now in the production cycle and they have produced 222,874 bbls [34,434m3] of oil by 30th September 1988 with an overall oil steam ratio of 3.0832.
There was no primary production.
Planning of an Appraisal/Development Program for the Complex Khuff Carbonate Reservoir in the Yibal Field, North Oman
Authors: Bos C. F. M. 
Published: December 2007

Abstract
In 1986, oil was discovered in the Permo-Triassic Khuff carbonates of the Yibal Field in North Oman. This formation, which covers extensive areas of the Arabian Peninsula and Arabian Gulf, had hitherto never tested oil and the Yibal Khuff accumulation is therefore unique in the region.
Dry but sour oil rates of up to 1 200 m3/d [7 550 bbl/d] were tested at a depth of 3 036 m [9 960 ft]. Subsequent appraisal wells, however, revealed the reservoir to be highly complex and dramatically downgraded initial expectations of an early, large scale development.
This paper describes the stepwise approach adopted to meet the dual objective of better defining the reservoir whilst at the same time developing the reserves in a cost effective way.
To this end, an appraisal/development plan has been designed consisting of the installation of limited liquid and gas handling facilities, further appraisal drilling, coring and extensive production testing.
The synthesis of production test, reservoir geological and petrophysical interpretations has allowed the construction of a conceptual reservoir model consisting of a prolific, fractured crest where early gas breakthrough hampers the oil productivity and marginal, low permeable flanks. Areas of non-producible oil have also been identified.
Evaluating Tracer Response of Waterflood Five-Spot Pilot: Dukhan Field, Qatar
Authors: Al-Dolaimi A. M. , Berta D. , Dempsey M. J. , Smith P. J. 
Published: December 2007

Abstract
A five spot pilot waterflood was designed to investigate the reservoir potential of the Upper Reservoir Section, Arab ‘C’, Dukhan Field, Qatar. The long term plan involves development of these reserves which have been by-passed by the peripheral waterflood presently generated through the Lower Section. The monitoring programme over the five year period of the pilot has consisted of pressure and production/injection testing, open hole and cased hole log surveying and processing, a full suite of laboratory measurements on the produced effluent water and a full programme of data acquisition on an observation well. Radioactive and chemical tracers have been injected and their activity regularly determined in the produced water. These data plus the production water-cuts and salinities represent important evidence in unravelling the complex behaviour of the Upper Reservoir Section. This complexity stems from the highly heterogenous reservoir material and the variable production and injection rates.
This paper describes a three pronged approach to analysing these data:– AAnalytical Tracer EvaluationBSingle-Well ModelCThree Dimensional Models of the Region
In Part A we apply analytical tools to interpret the tracer and salinity response. By assuming constant production rates, no permeability variation and no cross flow a broad characterisation of the reservoir is obtained.
In Part B the variability in the reservoir and injection/production rates can be accommodated by the numerical simulator. Moreover, a tracer option in the simulator is used so that the formation, injection, and tritiated waters can be individually tracked. The results of Part B suggest that a reservoir characterisation based on many separate layers is unnecessary since much of the variability in tracer response can be produced by a few layers.
Finally, in Part C by developing a three dimensional 10000 cell model of the five-spot area, based upon the findings from A and B and a previously constructed coarse full field model, the dependency between the different well responses can be more fully understood.
Enhanced Recovery by Horizontal Drainholes
Authors: Dijkum C. E. van 
Published: December 2007

Abstract
In 1986 PDO has drilled 3 horizontal dralnholes to gain experience with the horizontal drilling technique and to assess the gain in well productivity. The three wells (horizontal section 65-120 m) have been drilled in low permeability formations (permeability 1-30 mD) with oil columns ranging from 20 to 60 m.
In view of the thin oil columns and drilling difficulties in overlying shales the dralnholes were drilled by a small radius (9-12 m) technique. The drilling of the horizontal sections was completed in 42 days. No problems were encountered during drilling.
Analysis of the production performance shows that a horizontal drainhole can enhance oil production substantially, provided its location with respect to the 0WC is optimal and its orientation is such that in a heterogeneous formation it penetrates several layers.
To improve the understanding of the horizontal drainhole simulation studies have been carried out to match production history and pressure build up test. Both the historical and the predicted performance of a horizontal well are compared with a vertical well. The actual and simulated performance of the horizontal well shows that oil production Is enhanced by a factor two to three.
Another objective of horizontal wells may be the suppression of waterconing. A scouting study on the performance of a horizontal well in a high permeability reservoir with high watercut shows that, contrary to expectation, no significant improvement in oil production was calculated.
Petrology and Diagenetic Effects of Carbonate Rocks: Jurassic Arab C Oil Reservoir in El Bunduq Field, Offshore Abu Dhabi and Qatar
Authors: Honda N. , Obata Y. , Abouelenein M. K. M. , Kitagawa H. , Negishi T. 
Published: December 2007

ABSTRACT
The depositional and diagenetic model of the Arab C4 Reservoir (Upper Jurassic) in EL Bunduq Field is constructed based on core studies (sedimentological core examination, petrographical analysis of thin sections, petrophysical core analysis, scanning microscopy, cathodoluminescence analysis, X-ray diffraction analysis) and wireline log data from 13 cored wells.
The Arab C4 Reservoir which comprises one of the main oil reservoirs in the Field is composed of inter-bedded limestones, dolomites, and anhydrites displaying lagoonal, tidal flat, and sabkha environments. The following seven different lithofacies have been identified. (1)Bioclastic Grainstone Lithofacies(2)Pelletoidal Grainstone Lithofacies(3)Oolitic Grainstone Lithofacies(4)Laminated Carbonate Mudstone Lithofacies(5)Mottled Carbonate Mudstone Lithofacies(6)Algal Boundstone Lithofacies(7)Nodular Anhydrite Lithofacies
Reservoir quality is best within lime grainstones and dolomitised grainstones. The original depositional textures have the most important effects on reservoir quality. For example, grain-supported limestones often preserve their original intergranular porosities. While limestones with mud matrix have generally poor reservoir quality. Moreover, the depositional environments and primary pore systems within the sediments themselves have a great influence on the subsequent diagenetic processes.
Deposition within mainly intertidal to supratidal environments resulted in early surface related diagenetic processes and then the sediments were subjected to later stage, deeper burial diagenetic processes.
The following processes can be recognized; (1)Surface Diagenetic Processes Micritisation,Pyrite Formation(2)Early Stage Diagenetic Processes LeachingCalcite CementationDolomitisationAnhydrite GrowthEarly Compaction(3)Later Stage Diagenetic Processes Later Compaction and Pressure SolutionBitumen ImpregnationFracturing
The most significant diagenetic processes affecting the reservoir quality are leaching, calcite cementation dolomitisation, and replacement by anhydrite which took place early in the diagenetic history within near surface environments.
Inversion Technique To Determine the In-Situ Stress Field From Fracturing Data
Authors: Aadnoy B. S. 
Published: December 2007

ABSTRACTTypically one assumes that the two horizontal in-situ stresses are equal in borehole stability studies. This simplification has been necessary due to lack of information. The new method presented here distinguishes between the in-situ stresses and estimates the magnitude and the direction of each of the two horizontal in-situ stresses. The input data used are the leak-off fracturing information.The new method uses stress transformation equations to take advantage of the directional characteristics of offshore boreholes. By including the hole inclination and the azimuth, one can solve for the two unequal horizontal in-situ stresses. The model results in finding the inverse of an overdetermined system of equations. A field study demonstrates the method.
The Separation of Electrolyte Effects From Rheological Effects in Studies of Inhibition of Shales With Natural Moisture Contents
Authors: Beihoffer T. W. , Dorrough D. S. , Schmidt D. D. 
Published: December 2007

ABSTRACT
The shale rolling test is a common procedure that is used to measure the interactions between drilling fluids and shales. This study found that the results of the shale rolling test depend on the moisture content of the shale, the shale composition, the viscosity of the test fluid, the rotation speed of the rollers, and the test temperature. To obtain reproducible results, all of these variables must be carefully controlled.
The rheological behavior of the test fluid has the strongest influence on test results. This led to the conclusion that the rolling test is only valid for unviscosified drilling fluids. This severely limits the applicability of the test.
Drying the shales caused changes that influenced test results. This indicates that, when possible, tests should be run with shales of native moisture content.
When test variables are carefully controlled, the rolling test is a useful technique to measure the interactions of electrolytes with shale granules in partially formulated drilling fluids.
Design and Synthesis of Shale Stabilizing Polymers for Water-Based Drilling Fluids
Authors: Sheu J. J. , Perricone A. C. 
Published: December 2007

ABSTRACT
Troublesome shales can cause costly downtime due to stuck pipe, hole-fill and even hole abandonment. Much research effort has been expended in an attempt to better understand shales and their interaction with drilling fluids. A combination of cations with water soluble polymers are known to effectively stabilize many shale formations including combinations of potassium chloride with partially hydrolyzed polyacrylamide (PHPA). This paper will focus on general aspects of how PHPA and other polymers stabilize shales. In the stabilization of shales by various chemical agents, the specific mechanism by which polymers stabilize shales has not been studied in detail. A shale stabilizing mechanism based on polymer adsorption onto clay surfaces and how solution properties of polymers affect this mechanism, will be proposed. Several simple approaches to the design and the synthesis of improved shale stabilizing polymers for water based drilling fluids will be discussed.
A commonly used shale disintegration test has been modified for use in screening many shale stabilizers. This test method is capable of generating statistically reproducible results and has provided some mechanistic information on shale stabilizers. Such information is valuable and has led to the design and the synthesis of a new improved polymer useful for shale stabilization in water-based drilling fluid systems.
Economic and Performance Analysis Models for Solids Control
Authors: Lal M. 
Published: December 2007

ABSTRACT
This paper presents two models which provide an analytical basis for the economic analysis and selection of proper solids control equipment. The economic analysis model predicts the relative savings in mud dilution and wastes disposal costs for various percents of drilled solids removal and for the closed-loop implementation. The performance analysis model analyzes the performance of a given solids control system in terms of its solids removal capacity. A recent case history illustrates the importance of these models and confirms the savings predicted for a closed-loop implementation.