bluuebunny/crossref_metadata_2025_split huggingface dataset:
Case Study: Performance of a Complex Carbonate Reservoir Under Peripheral Water Injection
Authors: Rahman M. , Sunbul M. B. , McGuire M. D. 
Published: December 2007

ABSTRACT
The paper presents a case study of a major carbonate reservoir under peripheral waterflood. It illustrates the importance of good surveillance data not only for monitoring performance but also for characterizing reservoirs. It shows that fluid flow in a lithologically complex and highly stratified reservoir can be much simpler than would be projected from geology alone. The paper also discusses a production strategy that has improved areal and vertical sweep.
In this study, the available surveillance data including well performance, geochemical analysis, cased and openhole logs were utilized to determine water encroachment patterns, areal and vertical sweep, and identify the reasons for lack of sweep in certain areas of the reservoir. The observed flood performance has been incorporated into an updated geological model of the reservoir that will form the basis for a forthcoming 3-D simulation model.
Three-Phase Relative Permeability of Limestones Having Bimodal Pore-Size Distribution
Authors: Marek B. F. , Hartman K. J. , McDonald A. E. 
Published: December 2007

ABSTRACT
Reservoir engineering calculations frequently require consideration of coexisting oil, water, and gas phases. Such three-phase flow occurs when a reservoir is produced below the solution gas/oil pressure or when enhanced recovery processes such as water-alternating-gas flooding or simultaneous gas/water flow occurs. For this reason, reservoir simulators generally include three-phase relative permeability prediction methods. Two- and three-phase relative permeabilities were measured on a mixed wettability carbonate sample having a bimodal pore size distribution. The results of the three-phase measurements were compared with values obtained from prediction models based on two-phase data. A model has been proposed that includes a "trapped gas effect" which leads to a reduced waterflood residual oil saturation. The proposed model appears to be superior to the Stone Model II, especially in the low oil saturation range.
Fracture Patterns of Natih Formation Outcrops and Their Implications for the Reservoir Modelling of the Natih Field, North Oman
Authors: Mercadier C. G. , Mäkel G. H. , Turkse Shell N. V. 
Published: December 2007

ABSTRACT
A quantification of fracture dimensions and spacings has been obtained from a survey of outcrops of Middle Cretaceous Natih Formation carbonates in simple fold structures in North Oman. From the distribution of cross-axial and longitudinal extensional fractures in thickly-bedded limestone, our geological model has average matrix block dimensions of:
– 50 m (length) × 5 m (width) × 10-20 m (height) in gently dipping areas, – 50 m (length) × 0.5 m (width) × 10-20 m (height) in steeply dipping areas.
These blocks contain and/or are intersected by cross-axial shear fractures with variable spacings.
These results have been applied to the fractured limestone reservoirs of the Natih Formation of the Natih Field, located some 50 km to the west of the jebels studied. This field is a NW-SE trending anticline which contains a STOIIP of 500 million m3. Open, cross-axial (NE-SW trending) fractures dominate as shown by electrical borehole imagery, core, and tracer testing studies.
From the outcrop and Natih Field subsurface data, the open, cross-axial fractures are inferred to be regularly distributed over the Natih structure with a spacing of 1 to several tens of m (extensional fractures), and 0.1 to 2 m (shear fractures). The spacing of the closed or only partly open longitudinal and shear fractures varies probably more over the structure because it is more sensitive to lithological and dip changes than that of other fracture types. These data provided realistic fracture parameters for the Natih Field integrated reservoir modelling that was carried out to study the production mechanism of the field.
Field Performance of a Horizontal Well
Authors: Arima E. , Hirokawa S. 
Published: December 2007

ABSTRACT
This paper presents a field example of a short-radius horizontal drainhole which was completed by sidetracking an existing vertical well. The main reservoir characteristics are unconsolidated sand, high permeability and increasing production water cut due to strongly active bottom water. The horizontal drainhole was aimed at increasing the critical rate under which oil can be produced free of water. Since the reservoir has a high transmissibility (Kh/μ), a vertical well is enough for meeting the target rate as long as water cut is maintained at a low level.
Performance was compared between a vertical well and a horizontal drainhole using analytical methods before implementing the horizontal recompletion. As expected, the horizontal drainhole has successfully maintained a high oil production rate without any water cut for more than one year. The field data proved the effectiveness of the horizontal drainhole on water control. Although recompletion to a horizontal drainhole resulted in successful production performance, there still remains room for improvement in well completion techniques. The unconsolidated sand required the use of heavy weight mud and caused difficulties during drilling. Sand problems had to be tackled and required a detailed design for well completion. In this paper, the drilling procedures and problems are also briefly mentioned.
Horizontal Drilling vs. Acid Fracturing: A Review of Results in the Upper Zakum Field
Authors: Fada’Q A. S. , Al-Tamimi Y. K. 
Published: December 2007

ABSTRACT
In recent years, horizontal drilling has captured much attention in the oil industry. Acid fracturing on the other hand, has been long before adopted by the industry, both techniques have proved to be effective in enhancing the productivity of oil wells, their theory and merits have been tackled by numerous technical papers. However, in the majority of these works, comparisons were invariably made by discussing the performance of a vertical well versus a horizontal one, or fractured versus unfractured. The following paper is intended to present actual case histories comparing the performance of a fully completed horizontal well with that of an acid fractured well in the same field and within the same reservoir (carbonate), thus making the comparison more representative, because important "flow parameters" related to reservoir characteristics are similar in both cases. The paper will describe the environment in which these two techniques were field tested and present conclusions on the production enhancement achieved in each case, brief description of the additional cost incurred will also be highlighted.
The Role of Reservoir Simulation in Identifying Secondary Development Prospects
Authors: Tosdevin M. A. , Abdulla I. A. 
Published: December 2007

ABSTRACT
A major Integrated Petroleum Engineering Study of the Bul Hanine Arab D, the most prolific reservoir Offshore Qatar containing a STOIIP of 2.4 billion bbl (382 Mm), has been completed. This paper will present not the detailed construction, history match and prediction runs of the model but, rather, concentrate on the steps leading up to identification of target zones for future redevelopment (the remaining oil).
Due to the large size and complex geology of this carbonate reservoir it was impossible, even if it would have been desirable, to design a simulation model to examine in detail all aspects of the historical and future development. This being the case a model was constructed which aimed to predict the likely future production of the existing wells and similarly completed new wells and to identify the location of the remaining oil which could be the target of an altogether different method of production. In the end two unswept zones have been identified for future development, one of which may involve the drilling of thirty horizontal wells. The necessity of studying the expected performance of the new type of wells with simulation models designed specifically for the purpose will be highlighted together with the need to perform field trials to confirm their results.
Effect of Stochastic Faults on Reservoir Permeabilities in Presence of Stochastic Shales
Authors: Abu-Elbashar O. B. , Daltaban S. T. , Wall C. G. , Archer J. S. 
Published: December 2007

ABSTRACT
Due to the resolution limitation of seismic techniques, faults shorter than the distance between seismic lines, or faults with very small throws axe often not detected. The impact of such small (stochastic) faults on reservoir transmissibility can be extremely detrimental, especially in intensively faulted areas. Such faults are unlikely to be detected by well tests. In the presence of stochastic shales – which smear on the stochastic fault planes – the reservoir permeabilities can be considerably reduced as a result of the vertical barriers to horizontal flow created by the smeared fault planes. In this paper, a technique is presented for modelling such stochastic faults and for calculation of their effect on reservoir permeabilities (transmissibility). Continuity distribution functions (CDF) for stochastic fault dimensions are derived from published literature, and triangular distribution functions are used in modelling the faults.
The permeability computations are done in three stages: (i) calculation of the effect of stochastic shales on permeabilities (to obtain effective permeabilities for the reservoir blocks), (ii) generation of stochastic faults and specifying the faults encountering the block under consideration, (iii) and evaluation of the effect of the smeared areas of these faults on the reservoir permeabilities. These calculations are performed by a set of specially coded computer programs.
The calculations reveal the impact of stochastic faults on reservoir permeabilities (especially horizontal permeability) and suggest that the effect of stochastic faults should be assessed before simulating reservoir performance.
Performance Evaluation of Caustic Pilot Project of North Gujarat Oil Field, India
Authors: Goyal K. L. , Gupta R. K. , Nanda S. K. , Paul A. K. , Sharma P. 
Published: December 2007

ABSTRACT
This paper describes the progress and experience gained in North Gujarat oi1 field, caustic flood pi lot project. Laboratory investigations on acid number and interfacial reduction studies, to firm up the optimum concentration of caustic solution, encouraged the investigators to undertake further flood studies on actual cores and long core packs, SEM Micrograph studies were also conducted to evaluate the effectivity, reactivity and absorptions characteristics. Based on these investigations an inverted 5 spot pattern on a 10 acre pilot area was choosen. A 0.1 PV preflush of Sodium carbonate solution was injected in Dec. 1987. This was followed in July 1988 by 0.2 PV of 0.25% caustic solution followed by chase water injection started in March 1989 and still continues.
At the time of writing this paper in March 1989, 23% additional oil has already been produced from the pilot area. The pilot is sti11 producing oil, with 40 to 45% water cut and some emulsion. The final recovery is expected to be around 38%. This incidently matches well with the laboratory results. The pi lot performance so far had been satisfactory. No scaling was observed in the production string. Slight increase in injection pressure of about 20 kg/cm2 was observed. This increase, however, was shortlived. This further confirmed the laboratory investigations that emulsification, as a result of decrease in interfacial tension, and subsequent demulsification to release the caustic once again, seems to be the predominently dominant mechanism responsible for enhanced recovery of oil.
Well Test Analysis of a Well With Multiple Horizontal Drainholes
Authors: Karakas M. , Yokoyama Y. M. , Arima E. M. 
Published: December 2007

ABSTRACT
This paper presents interpretation of several transient tests conducted in a well with multiple horizontal drainholes. The subject well is located in the offshore divided zone of Saudi Arabia and Kuwait and was initially completed as a vertical producer. Recently, two medium-length horizontal drainholes, each in a separate layer, were drilled from the existing casing of this well. In order to evaluate the effectiveness of the horizontal completion, the well was subjected to four production tests before and immediately after the drilling of each drainhole. These flow tests were analyzed in detail to determine important reservoir and production characteristics. The observed pressure responses are compared with those obtained from analytical and numerical models. A discussion on the practical aspects of well test interpretation in horizontal drainholes is also provided.
Numerical simulations show that, for transient analysis purposes, most multiple drainhole systems can be approximated by an equivalent single-layer, single-drainhole systems. Additionally, the results demonstrate the importance of drainhole orientation when the vertical communication between the producing layers is not restricted by flow barriers.
Characterization of Bahrain Field Oil and Gas Using Semicontinuous Thermodynamics
Authors: Wolff M. , Al-Mahroos F. M. 
Published: December 2007

ABSTRACT
This paper describes the use of semicontinuous thermodynamics1 to model Bahrain field oil and gas. This new method for heavy hydrocarbon fraction characterization is shown to be both simpler and more accurate in matching experimental data than conventional methods. Two separately tuned oil and gas models are then combined in a successful match of experimental data from an oil swelling study.
A Variable Cell Model for Simulating Gas Condensate Reservoir Performance
Authors: Al-Majed A. A. , Dougherty E. L. 
Published: December 2007

ABSTRACT
A variable cell model for simulating gas condensate reservoir performance has been developed. The model closely approximates predictions of conventional compositional models but would only require a fraction of the computation time. The characteristic trend of oil saturation profiles, which is exhibited when gas condensate wells produce below dew point pressure, was utilized to divide the reservoir into three concentric regions. Each region is simulated by one cell, and the volume of each cell is varied as production continues. Dew point pressure and phase behavior of the reservoir fluid control expansion of the inner first and second cells and contraction of the exterior third cell.
The model was used to study the effect of liquid flow on well-stream fluid composition. Also, the influence of reservoir fluid phase equilibria data on the extent of two phase flow dominated region was investigated.
Factor Affecting Mercury Capillary Pressure Behavior of Saudi Arabian Carbonate Reservoir Rocks
Authors: Al-Fossail K. A. , Saner S. , Asar H. K. , Hossain M. 
Published: December 2007

ABSTRACT
Capillary pressure can be viewed as the pressure required to drive a fluid through a pore throat, with greater pressure being required as the pore throat becomes smaller. The size and distribution of pore throats within a host rock control its capillary pressure characteristics, which in turn control fluid behavior in the pore system. The pore geometry of carbonate rocks has as great influence on the ability of the rock to contain and produce oil and gas as do porosity and permeability. This has been demonstrated by examining a large number of samples from a Saudi Arabian carbonate reservoir. By studying the lithology and genesis of the rocks, and comparing families of capillary pressure curves, it was possible to establish very clear mutual relationships.
The mercury injection technique followed by ejection and reinjection was used to determine capillary pressure behavior for each sample. Experiments were also performed to test the plug size and surface effects on capillary pressure characteristics. A detailed interpretation of the data was carried out in order to extract various correlation parameters. These data were combined with basic rock properties and incorporated in generating families of capillary pressure curves for several carbonate rock types, and in the computation of pore throat size distributions.
Experimental data are presented using J-Functions for the correlation of capillary pressure and saturation relations for all samples. It is shown that the correlation improves significandy when the samples are grouped together based on the rock lithology.
Magnetic Logging: Borehole Magnetostratigraphy and Absolute Datation in Sedimentary Rocks
Authors: Lalanne B. , Bouisset P. , Pages G. , Pocachard J. 
Published: December 2007

ABSTRACT
A new magnetic logging tool has been designed and developed for precise and reliable in-situ magnetic measurements in the sedimentary formations encountered when drilling for oil.
The tool consists of two probes, measuring respectively the in-hole effect of the Earth's magnetic field and the magnetic susceptibility of the rocks, and is operated as a standard logging tool.
A proper combination of these magnetic measurements provides the determination of Natural Remanent Magnetization polarity, from which the polarity of the Earth's magnetic field at the time of sedimentation is deduced.
A magnetostratigraphic sequence is obtained for each well, and appears to be similar to the Magnetostratigraphic Reference Scale.
Application of this method to wells in the Paris basin (France), gives good results for correlations and absolute age determination.
Further comparison of results obtained from magnetic measurements and from sequence stratigraphy applied to conventional logs, shows that sequence boundaries can be diachronous in wells 80 km apart. Although the potential of magnetic measurements is still under investigation, the first encouraging results clearly show that the new dating method presented in this paper can be very helpful in petroleum geology.
Petrophysical Approach to Description of a Producing Fractured Basement Reservoir
Authors: Khalil M. M. , Pigaht J. 
Published: December 2007

ABSTRACT
A study was initiated with the objective to provide a better estimate of petrophysical parameters in a producing fractured basement reservoir. Emphasis was put on fracture and matrix porosity determination and its vertical and areal distribution. This uas essential in order to accurately define STOIIP as well as to improve the reservoir description and provide a data base for modelling studies. This paper gives an insight into the techniques applied to classify different rock types and the approach taken to compute the mineralogical model as basis for the porosity evaluation with minimum available core data to calibrate the results.
With the help of a program to identify electro-facies a minaralogical model was assigned to each facies and the petrophysical constants were then computed. Whenever possible test and production logging data and Formation Micro Scanner data were utilized to confirm the study results.
Based on the analysis it was possible to subdivide the fractured basement body into segments. Problems in determining porosity as well as water saturation in this type of reservoir are highlighted and the need to initiate a world-wide data base for granitic rocks is stressed.
Geological Controls on Reservoir Quality of Arab Formation in Satah Field
Authors: Kawaguchi K-l. 
Published: December 2007

ABSTRACT
The Upper Jurrasic Arab Formation in the Satah Field is composed of two major rock units, i.e. shallow marine carbonates and cyclic carbonates-anhydrite sequence. The former is defined as the Arab D zone, while the latter is divided into three zones, i.e. Arab A, B and C in descending order. The Arab C and D zones comprise hydrocarbon bearing formations in the field.
The Arab D reservoir is characterized by upward shallowing sequence. Its lower and middle portions are dominated by mud supported facies deposited on a shallow shelf, while its upper part is composed of various lithology types resulting from upward shallowing system. Total eight lithology types were identified within the Arab D reservoir. The petrophysical characteristics of the Arab D sequence is determined by the original sedimentary fabrics and by various diagenetic processes. Leaching and dolomitization can enhance both porosity and permeability, whereas bitumen fills associated with paleo O.W.C. and matrix cementation related to paleo acquifer reduce the reservoir quality. In general, below "Bitumen Mat" both porosity and permeability deteriorate rapidly. In other word, the Arab D reservoir is considered to be bottom sealed reservoir. According to the lithological and petrophysical variations, the Arab D reservoir was subdivided into fifteen reservoir layers.
On the other hand, the Arab C zone is made up of alternated carbonates and anhydrite and was accumulated under the various depositional environments ranging from supratidal-sabkha to subtidal conditions. The carbonates are dominated by grain-supported facies and divided into six lithology types. The original fabrics of the sediments play an important role on the reservoir quality, as well as several diagenetic events. Good reservoir characteristics are distributed where the secondary pores by leaching and dolomitization are connected with the primary pore networks. Major porosity reduction as observed in the Arab D reservoir is not recognized.
Such geological analysis is considered to be not only essential but helpful for the reservoir layering scheme and simulation study.
Impact of Oil Spill on Intertidal Organisms in Bahrain
Authors: Mohamed S. A. 
Published: December 2007

ABSTRACT
This study was carried out after a major oil spill hit the coasts of Bahrain in 1988. A total of fifteen stations around the Island of Bahrain were monitored for a period of six months in order to measure the impact of the spill on marine organisms and in particular those living in the intertidal zone. Large quantities of heavy hydrocarbons accumulated on the shores and caused death or serious damage to many organisms, including birds and fishes. The spill first hit the northwest shores. The oil spill was also reported to be the main factor in damaging the traditional fishing traps in the coastal waters, which caused serious effects on the fish catch for seven months.
The Application of Model Testing to Offshore Mobile Platform Design
Authors: Barkley W.B. 
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers Inc.

Abstract
Model testing of offshore mobile platforms and related marine equipment, as a means for improving designs and increasing operating profits, is currently receiving considerable attention. Model testing presents the best method for investigating the dynamic characteristics of mobile platforms, thereby predicting the force and motion platforms, thereby predicting the force and motion response in waves and wind.
The validity of scaling model results to fullscale proportions is predicated upon the application of appropriate engineering factors which have been derived from experiments in fluid mechanics. For most platform parameters, scaling accuracies to within 5 per cent - 6 per cent are obtainable.
Improved scaling accuracies may be anticipated in the future as a result of improved modeling techniques and additional correlation between model data and prototype performance. Development of computer-implemented mathematical simulations promises additional assistance.
Although design of offshore platforms and related equipment is influenced by a number of factors in addition to hydrodynamic considerations, new and improved model test data, correlated with prototype results, may be expected to accelerate technical advancement. These factors, combined with the potential for new concept development, will influence future industry planning.

Introduction
Model testing of offshore mobile platforms and related marine equipment is currently receiving greater attention than ever before. The reason for this increase in model testing activity stems primarily from the progressive movement to deeper water and the attendant requirements for floating structures.