bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Arab-D Depositional Model, Ghawar Field, Saudi Arabia
Authors: Meyer F. O. , Price R. C. 
Published: December 2007

ABSTRACT
Bedding characteristics and the vertical distribution of lithofacies divide the Arab-D carbonate reservoir of Ghawar Field into a Lower Arab-D and Upper Arab-D zone. The Lower Arab-D consists of a basal rhythmically interbedded muddy and grainy interval that exhibits TA, TB, TE, and TH classic turbidite divisions, and an overlying massive interval of amalgamated carbonate sand and gravel beds that are graded and hummocky cross stratified. The upper part of this massive interval passes upwards into graded and ungraded skeletal sands and forms a short transition zone into poorly bedded skeletal carbonates of the Upper Arab-D section.
Upper Arab-D passes gradationally upwards from muddy Stromatoporoid framestones, through a Burrowed Skeletal- Peloidal, Cladocoropsis, Foraminiferal, Mixed Skeletal-Peloidal, cross bedded Oolite lithofacies sequence, and into a transitional zone of Mixed Skeletal-Peloidal sands that intercalates with a thick zone composed mainly of nodular anhydrite.
The Arab-D carbonates studied represent part of the fill and subsequent progradation depositional history into separate intrashelf basins situated both North and East of the field. Their stratigraphy and depositional features are consistent with a prograding storm dominated shelf model in which in situ skeletal carbonate production embraces a broad belt of stromatopoids, Cladocoropsis and foraminifers located roughly between fair weather wave base and the lower shoreface. Carbonate transport directed shoreward, mainly by day-to-day processes, includes cross-bedded and hydrodynamically sorted medium to fine skeletal and non-skeletal sands at the top of the Arab-D. Stormgenerated turbidity currents transported carbonates seaward below fair-weather wave base to as suggested by graded and hummocky cross bedded Lower Arab-D strata.
The two different styles of deposition exert significant controls on reservoir performance. Storm sequences (Arab-D, Zone 3) form layered reservoir horizons whose best permeability exists in thin, basal grainy textures of proximal deposits, but thicken as grainy carbonates increases in a more proximal direction. Facies belts in Zone 2 form shingled reservoir zones which climb north- and eastward toward the intrashelf basins. This type of reservoir reconstruction differs significantly from the previous layer-cake model, and should more accurately reflect the geologic architecture needed in reservoir modeling.
Sequence Stratigraphy and Source Rock Potential of Middle Cretaceous (Upper Wasia Group) in West Abu Dhabi
Authors: Azzam I. N. , Taher A. K. 
Published: December 2007

ABSTRACT
The Middle Cretaceous "Upper Wasia Group" in West Abu Dhabi is divided into four Formations: the Shilaif, Mishrif, Tuwayil and Ruwaydha. In this paper, a new stratigraphic subdivisions based on sequence stratigraphy, for the "Upper Wasia Group" is introduced. It consists of three distinct Sequences: I (Mishrif/Shilait), II (Tuwayil) and III (Ruwaydha) that were deposited in the area from Late Albian to Turonian.
Mathematical modeling applied on the Shilaif Formation (Sequence I) study· area, has indicated However,.the volume of hydrocarbon accumulations discovered in the Middle Cretaceous Upper Wasia reservoirs is much less than volumetric calculations of predicted oil-in-place. This demonstrates the generation of adequate volumes of oilfrom the Shilaif, which justifies further exploration activity.
Importance of Sequence Stratigraphic Concepts in Development of Reservoir Architecture in Upper Jurassic Grainstones, Hadriya and Hanifa Reservoirs, Saudi Arabia
Authors: McGuire M. D. , Koepnick R. B. , Markello J. R. , Stockton M. L. , Waite L. E. , Kompanik G. S. , Al-Shammery M. J. , Al-Amoudi M. O. 
Published: December 2007

ABSTRACT
The Upper Jurassic Hadriya and Hanifa carbonate grainstone reservoirs in Berri Field, Saudi Arabia, contain large reserves of Saudi Extra Light crude oil. New geologic models of each reservoir have been built using sequence-stratigraphic principles. These new models have a chronostratigraphic architecture which accommodates the facies transitions observed in cores sampled along the ramp-to-basin profile. Each reservoir contains, from oldest to youngest:(l) a highstand systems tract represented by aggrading and prograding grainstones, capped by a type-2 (subaqueous) sequence boundary; (2) a shelf margin wedge systems tract characteriz.ed by grainstones showing maximum basinward progradation; and (3) a transgressive systems tract typified by a series of backstepping grainstones capped by a surface of relative drowning.These new models clarify the elements controlling fluid movement within the reservoirs.
Development of the Ghawar Scale Squeeze Simulation Model: Using Core Analysis to Evaluate Treatment Chemicals
Authors: Lynn J. D. 
Published: December 2007

Abstract
Calcium Carbonate scaling problems have been detected in three of the Aramco Southern area Helds. As of 6/88, these fields have shown scaling in more then 70 % of the wet producers. The scaling has resulted in loss of production capability and created potential safety hazards throughout the production string, and into the gathering areas. Various methods are being evaluated in order to find a cost effective method of eliminating or controlling the scale problem. The following methods have been evaluated as possible alternatives to solve the problem: Tubing replacementPhysical or chemical removal of the scale (HQ)Down hole chemical injectionScale inhibitor squeeze
The method selected for application to the Arabian fields was the precipitation inhibitor squeeze. Core analysis is playing a major role in the development of the squeeze method, and in defining procedures which will optimize the field treatment.
The final result of the testing was a core based production model which could accurately simulate field behavior of inhibitor treated wells. The data would then be applied to optimization of early field trials. The generated data would then be applied to formulation of a mathematical model for field application. This paper will illustrate the various applications the core testing was used for, and show the relationship of laboratory data to the formation data, and describe the use of the core data in the optimization of the field treatment.
Evaluation of Water and Gas Pattern Flooding Using Horizontal Wells in Tight Carbonate Reservoirs
Authors: Mostafa Ismail 
Published: December 2007

ABSTRACT
ADCD has successfully drilled a number of horizontal wells in its different operating fields, to evaluate its effectiveness in solving certain reservoir problems. Field results confirmed that horizontal drilling is beneficial in enhancing well productivity/injectivity, and alleviating water caning or gas cusping problems. ADCD is currently investigating the feasibility of developing some of its tight carbonate reservoirs, containing large amount of oil reserves, using this new horizontal well technology.
A numerical simulation study was conducted to predict the performance of five-spot pattern development of those poor characteristics multilayered reservoirs using horizontal holes. Horizontal wells were modelled using ECLIPSE-200 enhanced feature of local grid refinement (LGR) where the mesh around the horizontal holes were strongly refined. The model was calibrated successfully against field transient test results of a horizontal well. After model calibration, 100-year prediction runs were performed to evaluate the effectiveness of water and gas pattern flooding with horizontal holes in terms of plateau rate and length, sweep efficiency and ultimate recovery. Previous work was conducted to compare horizontal versus vertical well performance and to study the inpact of different parameters on horizontal well performance.
In this study, emphasis was given to some critical parameters affecting the performance of horizontal pattern in this strongly stratified reservoir mainly; vertical permeability and orientation/positioning of horizontal holes. The effectiveness of different flooding fluids such as water, lean gas or gas followed by water injection was examined in terms of sweep efficiency and ultimate recovery.
Measuring Relative Permeability of High-Permeability Samples From Egypt
Authors: Potter Gary , Lyle G. L. 
Published: December 2007

Abstract
High permeability samples presents problems in handling and in measuring relative permeability. Gulf of Suez core samples frequently have permeabilities in excess of 1 darcy and can be extremely friable. The Gulf of Suez samples are used as examples to illustrate problems with sample stability and practices typically used to handle this type of core.
High permeability samples create problems in getting reliable unsteady-state gas displacing oil relative permeability because of the difficulty in getting the differential pressure high enough to prevent the capillary forces from dominating the flow. When running the test manually, the rate that data can be recorded limits the maximum flow rate and therefore the differential pressure that can be used. An automated unsteady-state gas displacing liquid permeameter was designed and built to improve the reliability of gas displacing oil data by allowing higher flows without problems with data recording.
The minimum differential pressure for unsteady-state relative permeability tests is discussed in terms of the capillary pressure. By using arguments derived from fractional flow equations and saturation profile measurements, the minimum differential pressure should be 10 times the capillary pressure for the saturations expected during the test.
Practical Aspects of Constructing a Large 3D Simulation Model of a Complex Reservoir
Authors: Phelps R. E. 
Published: December 2007

ABSTRACT
This paper presents the practical aspects of building a large simulation model of the Hanifa reservoir, which exhibits complex lithology and fluid movement patterns. It illustrates the important phases of construction and presents several innovative ideas used to analyze the massive amount of geological and engineering data. Some of the major modelling difficulties that were encountered during construction are also discussed.
Some of these techniques include: Team Concept.Use of a coarse grid model of the oil field area in the initial stages of history matching. Results would then be transferred to a finer grid model in the final stages of the history match.Derivation of facies-area specific J-functions from log data.Derivation of facies specific relative permeabilities and reconciliation of laboratory and field data.Use of a six million cell geological model to compute water saturations from J-functions.Developing a 3-D algorithm to model pressure and salinity changes through time.Developing perforation chronology charts to illustrate historic well completion and inflow performance.
In addition, the paper illustrates some of the benefits of the synergistic effort between simulation and reservoir engineers, and geologists that led to a more detailed and reliable simulation of the reservoir.
Gas Penetration into Deeper Strata in Aquifer Storage
Authors: Rzepczynski Walter M. , Katz Donald L. 
Published: December 2007

Abstract
In the development of aquifer storage much has been learned of the behavior and movement of gas when in contact with water under a pressure differential. This paper shows through observation that gas can penetrate deeper into the reservoir than penetrate deeper into the reservoir than anticipated in any one of three ways. First, as a gas wafer early in the gas injection cycle before gravity affects balance pressure effects. Second, vertically into deeper layers through some permeability and lithologic path which permeability and lithologic path which appears to be an easier way to move water through the injection strata itself. Third, downstructure below the expected gas bubble horizon because of higher permeability in that direction and variations permeability in that direction and variations in the reservoir characteristics.
Examples for each type of deeper gas penetration was presented along with penetration was presented along with various illustrations and explanations as to their causes. This behavior of the gas-water system reveals the nature and character of the reservoir stratum. Although this paper only gives a comprehension of the reasons for gas penetrating into deeper layers it recognizes that calculations for various models could be made to give quantitative answers. These calculations would predict the degree of gas penetration into deeper layers when the penetration into deeper layers when the horizontal and vertical permeabilities of the layers are known.
Introduction
One is reluctant to accept the concept that gas goes downhill on occasions but this is what appears to happen in aquifer storage under certain circumstances. Three types of gas penetration deeper into the reservoir than one would expect, will be described for aquifer storage operations. The first is a movement of the gas wafer during the initial injection operation before gravity effects have a chance to balance pressure effects. The second is the penetration of gas into layers deeper than the injection strata through some permeability path which appears to be an easier way to move water than through the injection strata itself. The third is the movement of gas off-structure below the expected storage horizon apparently because of permeability stratification and continued pressurization of water in a given direction.
Simulation of Coning in a Thin Oil Rim in a Fractured Reservoir
Authors: Gallagher John , Prado Luis , Pieters Johan 
Published: December 2007

Abstract
The prediction of coning behaviour is critical to assessing the development potential of thin oil rims and to forecasting performance during the thinning phase of oil rims in general, towards the end of field life. Although coning behaviour has been investigated extensively for homogeneous reservoirs, relatively little has been reported on coning in fractured reservoirs.
A simulation model has been constructed for investigation of gas and water coning in a thin oil rim in a fractured reservoir, undergoing gas/oil gravity drainage in the presence of a strong aquifer. The single well radial model has been used to estimate the watercut and GOR development against gross offtake for varying perforation position and well spacing.
The model is based on a type well from the Ghaba North Shuaiba reservoir, one of several low relief fractured carbonate reservoirs in Central Oman. These reservoirs are potential candidates for development by gas oil gravity drainage, implying the need to produce from oil rims of approximately 30m in thickness. This simulation study has consisted of a first part approximately reproducing typical Ghaba North well performance, followed by a second part with prediction runs which have assisted in estimating the feasibility of gas oil gravity drainage in Ghaba North. The simulation results suggest that a significant amount of extra oil can be recovered by gas injection with an initial production well spacing of 350 m. The wells should be completed in a relatively low position (10-15 m above the original OWC) and produced at relatively low rates (around 50 m3/d). This work may also be useful for forecasting performance of other ongoing gas oil gravity drainage developments in Oman. It is intented to build on this work by considering also horizontal wells and the sensitivity of coning behaviour to basic input data.
Fractured Reservoir Simulation: Case Studies
Authors: Boerrigter P. M. , van de Leemput B. L. E. C. , Pieters Johan , Wit Krijn , Ypma J. G. J. 
Published: December 2007

ABSTRACT
In this paper an overview will be given of some applications of a new modular reservoir simulator MoReS, developed at Shell's E&P Lab (Rijswijk, The Netherlands). Since the completion of a first prototype fractured reservoir simulator in 1989, the simulator has been used for several fractured field studies.
First a survey will be given of important physical mechanisms that are active during production of fractured reservoirs, and their modelling in a reservoir simulator. Subsequently some field applications will be described covering a wide range of recovery mechanisms and associated development options: -the relative effectiveness of gas/oil gravity drainage and water/oil displacement in reservoirs undergoin a prolonged period of depletion, and periods of water and gas injection,-re-infiltration of oil from fracture into matrix upon oil rim reversals in such reservoirs,-water/oil imbibition, either co-current or counter-current, and the scaiing-up from laboratory to simulation-gridblock and field scale,-water production in fractured gas reservoirs,-water and gas coning in fractured reservoirs with thin oil rims.
These applications have been extremely useful for demonstrating the robustness and practical applicability of the fractured simulation capabilities of MoReS, whilst at the same time providing operating companies with early results of the new tool. Applications to non-fractured reservoirs or EOR applications will not be presented here.
Interference Tests in Naturally Fractured Reservoirs Under the Influence of Gas Cap or Water Influx
Authors: Al-Bemani A. S. , Ershaghi Iraj 
Published: December 2007

ABSTRACT
Interference analysis in naturally fractured reservoirs can serve as an extremely effective reservoir characterization tool. Because of the conductive nature of fractures, rapid segregation of gas-oil in naturally fractured reservoirs is common place.Additionally, the upward movement of bottom water can rapidly displace the water oil contact influencing the behavior of individual wells. The purpose of the study is to address an important class of interfer-ence test where the contribution of gas-cap support or wa-ter oil contact movement can significantly affect the esti-mated parameters such as storativity and transmissivity. The theoretical framework needed to model interference re-sponse in a naturally fractured reservoir producing an oil zone overlain by a gas cap or affected by a desired outer boundary condition, including water-influx effects,is de-rived and discussed. General pressure response solutions (for the active and the observation well) are derived for a dual flow double porosity naturally fractured reservoir. Furthermore, the effects attributed to properties of indi-vidual wells such as wellbore storage and skin damage are incorporated in the general solutions and studied.
Deviations from the line source solution occur as a result of matrix, water-influx, or gas cap support to the fractured system. In case of the gas-cap effects, the deviation de-pends entirely on the contrast between fracture anisotropy parameter (λ1) and matrix-fracture interporosity parame-ter (λ), and between the total gas cap storage capacitance (1-ω1)and oil zone matrix storage (ω) for a particular radial distance between the active and observation well. On the other hand the deviation due to water-influx ef-fects depends on the distance from the boundary to an observation well.
A combination of matrix-fracture interporosity and any of the supporting systems can produce a non-uniform and extended or even multiple transition periods between the two line source solutions of a fracture dominated flow and of that of the total reservoir response.
During multiple well testing, differences between the re-sponse signal attributed to either gas cap or water-influx effects, if not taken into consideration, may be inter-preted as heterogeneity effects, or other extraneous in-terferences. Effects observed for gas-cap response, resem-ble pressure support, ordinarilly attributed to interference from a nearby injector. Both gas-cap support and slowly advancing water-influx affect interference tests with long duration.
Type curves presented in this paper improve diognostic capability of well test analysts in recognizing source and causes of pressure support in naturally fractured reservoirs.
On-Line Well Monitoring and Its Application in a South Oman Oil Field
Authors: Taylor R. D. H. , Nuttall R. C. H. 
Published: December 2007

Abstract
Connecting coriolis meters to rod pump controllers in a major Oman oilfield puts accurate on-line well test data on the production technologist's desk. Conventional test separator facilities have been rendered obsolete. Numerous benefits of this recent change are beginning to be realized.
New Well Testing Technology: A Portable Three-Phase Test Unit
Authors: Cary D. N. , Durrett M. G. , Al-Amir A.H. Abd Rab , Al-Nuwaigi K. A. 
Published: December 2007

ABSTRACT:
In the early 1980’s Saudi Aramco identified the economic advantage a multiphase well test meter could provide to their oil producing operations. Over the following years Saudi Aramco joined with Texaco to develop a tool to serve these needs.
This Multiphase Well Test Meter was installed and tested in two Saudi Aramco producing fields during 1991 and 1992. Test results, when compared to a conventional test separator, were favorable. Additional tests are underway to prove system reliability before installation in an offshore, unmanned environment.
Computer Design and Fieldwide Optimization for Gas-Lifted Wells
Authors: Lee H. K. , Liang Jun , Ader J. C. , Legget R. B. 
Published: December 2007

Abstract
A computer procedure and an optimal gas allocation model are presented for gas lift installation design and field wide optimization. The paper outlines the pre-design well performance analysis, system nodal analysis and the design procedure for mandrel spacing and valve sizing. It also describes the algorithm, criterion and implementation of the gas allocation model.
Examples which illustrate the computer design pro-cedure are presented. Results and production improvement after implementing the gas allocation model for the October Nubian field are also discussed.
Special techniques are discussed to accommodate changes in reservoir productivity and operating conditions. A re-design feature is presented for wells at which gas lift valves and mandrels are already installed. An economic and effective operation can be obtained through the redesign procedure. The optimal gas allocation model, which significantly improved field production, is discussed. The integrated study requires 3-D reservoir modeling, system nodal analysis and gas dis-tribution modeling.
An Assessment of Natural Fracturing in the Thamama Formation by Reservoir Surveillance
Authors: Gibson A. P. , Al Kaioumi Q. M. , El-Amin A. M. 
Published: December 2007

ABSTRACT
The presence of natural fracturing in the Thamama Reservoir was postulated following its discovery in 1958. The performance of this reservoir was poorly understood being based on information gathered from a small number of well tests executed during the 1960’s and 70’s. An up to date assessment of this reservoir was sought utilising the latest reservoir monitoring technology. The objective was to confirm the existence, magnitude and orientation of any fracturing in the Thamama reservoir. A further objective was to evaluate their distribution within the zones of the Thamama reservoir. The surveillance programme included multi-well interference testing, pressure build-up testing, production logging and water saturation monitoring. It was concluded from this study that there were many small vertical fractures, predominantly located in the dense limestone intervals, which gave rise to a strongly anisotropic reservoir transmissibility.