bluuebunny/crossref_metadata_2025_split huggingface dataset:
Producing Geisum Offshore Field Through Floating Production Storage and Offloading (FPSO) Facilities
Authors: Motaal A. A. Abdel , El Kholy Y. A. 
Published: December 2007

Abstract
Geisum Field is a small offshore oil field discovered in the Gulf of Suez- EGYPT. Success to develop the field depends largely on the utilization of FPSO facilities. This paper presents the design of optimum development plan for this marginal oil field. It presents the project operations conducted through a short time of fourteen months to install both field production and FPSO facilities. Also it includes the technical data about both field operations and facilities that are related to the success achieved to produce Geisum heavy and extreemly viscous crude oil.
Gas Injection in a Saturated Oil Reservoir
Authors: Murty C. R. K. , Al-Khayat S. A. 
Published: December 2007

ABSTRACT
This is a follow-up to an earlier paper (SPE 11491)1 presented at the Third Middle East Oil Conference in March 1983 wherein crestal gas injection into the gas cap of Arab ‘D’ zone followed by gas cycling was recommended. The main objective of this injection is to avoid gas cap shrinkage which would result in lost oil reserves if the oil band is allowed to migrate and resaturate the gas cap.
Lean Khuff gas is being injected into the gas cap via a crestal well since February 1986. The injection mainly offsets the associated gas production. The results thus far have been encouraging: (a)The reservoir pressure has gone up by 35 Psig (241.3 kPa).(b)The gas cap shrinkage appears to have been halted.(c)The water cut in the affected wells is decreasing.(d)The daily oil production rate from the zone has been stabilized.(e)No injected gas breakthrough is observed in any of the producing wells.
The production performance further points out that injeotion response is only felt in North area wells whereas water invasion from South continues. To counter the water movement and balance the voidage created by fluid withdrawals, an increase in the gas injection is recommended.
The paper presents a brief review of the production performance, discusses the results of gas injection and examines the future requirements.
Miscible Gas Injection: Surface Tension Effect in Case of a Separator Gas
Authors: Thiebot B. M. 
Published: December 2007

ABSTRACT
One of the most attractive recovery process, either in secondary or in tertiary conditions, is the gas injection under dynamic miscibility conditions. Under high reservoir pressure, a lean gas will develop a frontal dynamic miscibility process while a rich gas will develop a rear dynamic miscibility process under lower reservoir pressure.
It is shown from the experimental measurements of surface tensions and phases densities that, on the opposite of what is expected according to numerical simulation results, the process corresponding to the development of a miscible front with a rich separator gas as injection gas is intermediate between conventional high pressure and condensing gas drive miscibilities.
This was the case for a Middle East field, for which a lean gas and a rich separator gas were studied.
Slim tube experiments were conducted to determine dynamic minimum miscibility pressures while surface tensions and phase densities were determined during a multiple contact test study simulating the basic rear miscibility process at the trailing edge of the displacement front.
The surface tensions measurements put into evidence that: –In case of a rich separator gas, the dynamic miscibility process developed was neither rear, as predicted by the numerical simulation, nor frontal, but rather intermediate.–A better fit of the Parachor computation is obtained if the experimental determination of the molecular weight of the heavier fraction (Undecanes-plus) is performed during a multiple contact test study simulating the dynamic miscibility process of a gas injection.
Geohistory Analysis: A Key for Reservoir Fluid Distribution, Abu Dhabi, U.A.E.
Authors: Marzouk I. M. 
Published: December 2007

Abstract
Hydrocarbons were discovered in Abu Dhabi in Permo-Carboniferous, Permian, Triassic, Jurassic, Cretaceous and Tertiary reservoirs.
Reservoir fluids encountered vary from non-hydrocarbon gas, dry gas, wet gas/high condensate yield gas, light oil, medium gravity oil, heavy oil, bitumen and formation water.
Reservoir fluid distribution varies in space from one field to the other and in geologic time from one reservoir to the other and even varies within one and the same reservoir.
Unique fluid distribution patterns were reported from different fields in Abu Dhabi. These patterns have raised questions which need explanation.
Geohistory analysis, mainly burial and thermal history, maturity profiles, paleo-structures and migration mechanism have explained the process of reservoir fluid distribution in most of the hydrocarbon reservoirs in Abu Dhabi.
A fluid distribution model was constructed for each geologic age. These models will help in future exploration for hydrocarbons by developing exploration concepts and predicting reservoir fluid types in undrilled prospects.
The Lower and Middle Jurassic in Offshore Abu Dhabi: Stratigraphy and Hydrocarbon Occurrence
Authors: Hassan T. H. 
Published: December 2007

Abstract
The Lower and Middle Jurassic of Offshore Abu Dhabi is represented by a thick (1100–1700 ft.) sequence composed dominantly of limestone with minor dolomite and shale and is bounded at the top and at the base by major regional unconformities. The sequence consists of two formations: the Izhara Formation which is overlain by the Araej Formation. The Hamlah Formation which underlies the Izhara is customarily dated as of Early Jurassic age but in this article it is assigned to the Triassic. The Izhara and Araej were deposited in an extensive, shallow epicontinental sea. Reservoir development in the Izhara is generally poor but a number of reservoir units occur in the Araej particularly in the Uweinat and the Upper Araej. Porosity is generally less than 20 percent.
Hydrocarbons are present in the Izhara in only one structure but are known to occur in the Araej in at least fifteen structures in the Area. Geochemical analysis indicates three possible sources for the Araej hydrocarbons: the Upper Jurassic Diyab Formation, the Hamlah/Izhara and the Triassic Gulailah Formation. Geothermal modelling indicates that oil generation may have been initiated from the Gulailah in the Late Jurassic and from the other source rocks later in the Cretaceous. Gas generation from the Gulailah commenced in the Early Tertiary and later from the Hamlah/Izhara and the Diyab. The major migration directions of the hydrocarbons were mainly to the north and northeast.
Field Measurement of Borehole Closure Across Salt Formation: Implementation to Well Cementing
Authors: Kim C. M. 
Published: December 2007

ABSTRACT
Deformation of a borehole across a salt bed in the U.S. Gulf Coast was monitored in support of a well cementing design. The well was drilled using a drilling mud of 13.3 lb/gal density through a salt-anhydrite section situated at depths of 17560 to 17870 feet. With the mud in place, caliper runs were made to measure the change in borehole diameter with time. The mud density in the borehole was then increased subsequently and caliper runs repeated until no noticeable change in borehole diameter within a 30-hour duration was recorded. When the mud density was 17.3 lb/gal, the borehole finally stabilized. Induced stress around the borehole was calculated. A relationship between induced stress (or mud density) and change in borehole diameter was established. Optimum density of cement slurry for the well was obtained. Results of the caliper measurements, along with the field measurement procedures are presented.
Production Casing Erosion through Annular Injection
Authors: Richardson J. W. , Le K. M. , Riggs K. R. 
Published: December 2007

ABSTRACT
Normal waste fluids disposal in North Slope, Alaska oilfields includes large-scale underground injection through well annuli. This cost-effective disposal method has produced severe erosion in some production casings. A series of tests were run to quantify significant parameters that cause erosion: fluid volume, fluid velocity and sand content. From the observed erosion rates, the calculated wear equation constants were found to be consistent with other published values. As a result of the test described below, several steps have been implemented to reduce casing erosion: reducing injection rates and volumes, monitoring sand content, and changing casing head outlet configuration.
Analysis of Mass Transfer Mechanisms Occurring in Rich Gas Displacement Process
Authors: Lee S-T. , Lo H. , Dharmawardhana B. T. 
Published: December 2007

ABSTRACT
This paper aims to understand and quantify the mass transfer mechanisms occurring in a rich-gas injection EOR process. The analysis is based on results from laboratory experiments and one-dimensional compositional simulation work.
First, different laboratory tests, involving reservoir oil and solvent, are presented to illustrate their application to a preliminary understanding of in-situ solvent-oil mixing behavior and development of a proper equation-of-state (EOS) fluid characterization. Second, one-dimensional compositional simulation work based on the calibrated EOS was conducted to validate the simulator and the EOS by comparing the experimental slim tube data with the simulation predictions. Third, practical examples are presented to illustrate the various mass-transfer mechanisms that could occur during rich gas displacements.
For certain pressure, temperature and solvent-composition conditions, a miscible or critical fluid was predicted to occur in a slim tube. Furthermore, the critical fluid could occur either at the tail-end or at the front of the transition zone. The former case would confirm the mechanism of the classical condensing-drive multiple contact miscible process. The latter case has also been discussed recently in the literature for rich gas displacements.
At the prevailing reservoir conditions of interest, however, the displacement was a near multiple-contact-miscible process, characterized by a condensing-vaporizing mass transfer sequence and by a high oil recovery close to that of a multiple contact miscible process. Details of the switching from a condensing to a vaporizing process were investigated.
Finally, this work shows that, quite similar to the CO2-vaporizing drive processes, solvent density requirement can be an important parameter for preliminary screening of solvent compositions for rich gas projects.
Experimental Evaluation of Transition Metals Salt Solutions as Additives in Steam Recovery Processes
Authors: Rivas O. R. , Campos R. E. , Borges L. G. 
Published: December 2007

ABSTRACT
It is well documented by laboratory and field data that besides physical changes such as viscosity reduction with temperature and steam destilation, the steam injection processes are accompanied by chemical reactions which, as it has been the case in the M-6 steam drive project in the Bolivar Coast of Lake Maracaibo, produce large amounts of undesirable hydrogen sulphide gas. Depending on the type of crude and on the steam temperature, they can also produce an irreversible increase or lowering of crude oil viscosity.
To in-situ control the hydrogen sulphide production and to promote the lowering of the crude oil viscosity, it has been proposed to use transition metals salts solutions such as nickel sulphate as additives in steam injection processes. In this work, we present the results of an experimental study carried out to assess the effect of using such an additive.
The experimental plan consisted of both static and dynamic test. The concentration of the solution was varied to 1.5 wt. % nickel sulphate at a temperature of 240°C, typical of Venezuelan steam injection projects. Reconstituted and whole core samples from two Venezuelan bitumen reservoirs were used.
Obtained results show that the two bitumen samples undergo aquathermolysis, in presence or absence of reservoir sand, that results with reconstituted sands are similar to those obtained with whole core samples and that the use of the additive promotes a lowering in bitumen viscosity, both in static and dynamic test. In the dynamic tests, however, changes are more pronounced in shorter reaction times. In one case the oil viscosity was lowered 20 times.
Prediction of Xanthan Rheology in Porous Media
Authors: Cannella W. J. , Huh C. , Seright R. S. 
Published: December 2007

ABSTRACT
The flow behavior of xanthan in porous media has been investigated experimentally, and also theoretically using effective medium theory. In the experimental portion of this study, the rheology of a commercially-available xanthan broth was characterized in porous media and viscometers and compared for a wide range of polymer concentrations (300 to 1600 ppm), effective brine permeabilities (40 to 800 md), residual oil saturations (0 to 29%), temperatures (25° and 80°C), and rock lithologies (sandstones and carbonates). An apparent shear rate equation having no adjustable parameters was developed and proved to be effective in relating the flow behavior of a given polymer solution in porous media at one set of conditions to the behavior at all other porous media conditions tested as well as to the rheology in a viscometer. Although the shear rate dependence on flow velocity (first order) and effective permeability (negative one-half order) agrees with that predicted by traditional capillary bundle model approaches, the value of the experimentally determined constant coefficient is larger than those predicted by the models.
The basis for the shear rate equation employed above has been studied theoretically with the assumption that the xanthan solution rheologies approximately follow the power-law relation. The apparent viscosity for a power-law fluid flowing in a porous medium is derived employing the effective medium approximation of percolation theory. In this approach, a porous medium is modeled as a network of capillary tubes, in which the radii of tubes are randomly distributed using a prescribed probability distribution. The apparent viscosity expression obtained is similar to that from the capillary bundle model, but the coefficient values are different, as observed experimentally. This difference is a consequence of the connectivity of flow channels and their variable cross-section. Due to its shear-thinning nature, a power-law fluid flows mainly through the wide channels of porous media, and largely bypasses small-scale pore channels of the porous body. The capillary bundle model cannot describe this tendency of a shear-thinning fluid.
Computed Tomography Studies of 3-D Miscible Displacement Behavior in a Laboratory Five-Spot Model
Authors: Withjack E. M. , Akervoll I. 
Published: December 2007

ABSTRACT
This paper presents the results of computed tomography (CT) studies of three-dimensional (3-D) miscible displacements in a laboratory five-spot model. In the field, gravity forces resulting from a density difference between a miscible agent (solvent) and a reservoir oil may cause segregation and result in an overriding solvent tongue. The laboratory model used in these experiments is a one-quarter of a five-spot pattern (20 cm × 20 cm × 15 cm) with a porous medium constructed of spherical glass beads. Viscous and gravity forces are scaled within certain limits to represent conditions applicable to the field.
Displacements are conducted at mobility ratios of 7.5 and 22.4 over a range (approximately 2 to 23) of viscous-to-gravity force ratios (Rv/g). Previous five-spot recovery correlations, based on a combination of 2-D areal and 2-D vertical sweepout, are found to overestimate recovery for the 3-D displacements. At one pore volume injected, for example, recoveries range from approximately 10% to 30% lower than those indicated by earlier correlations. In contrast with 2-D behavior, recovery efficiency increases continuously with greater Rv/g. The displacement characteristics for 2-D flow typically show a single overriding solvent tongue; the 3-D displacement characteristics observed here typically include an overriding tongue with secondary fingers. These results provide new experimental data in true 3-D geometry, and reinforce concerns with extending previous 2-D concepts to flow in 3-D five-spot patterns.
Design of a Propagating Wave Resistivity Sensor in Order to Minimize the Influence of Borehole Fluids on the Sensor Response
Authors: Rodney P. , Bartel R. 
Published: December 2007

ABSTRACT
A propagating wave electromagnetic resistivity sensor has been developed which exhibits superior performance in low resistivity muds compared to the sensor previously available. The development of this sensor was a result of a careful analytical and experimental investigation of borehole effects on electromagnetic wave sensors. In its introduction, this paper summarizes the observed effects of borehole diameter and resistivity on the response of electromagnetic wave resistivity sensors; details follow in the body of the paper. Following this, a presentation is made of the experimental and theoretical methodology used to establish borehole correction curves. This method was used to optimize the response of an electromagnetic wave sensor and to develop a general model for the borehole response of electromagnetic wave sensors. This is an extremely simple mathematical model; because of its simplicity, it is significant that it works (using different coefficients) for both the improved and the older electromagnetic wave sensors. Borehole correction curves, as predicted by the model for both sensors, are in excellent agreement with experimental data over a wide range of mud resistivities. Accordingly, an accurate set of borehole correction curves is presented for both sensors. From these curves, it is apparent that borehole effects on the improved electromagnetic wave sensor are small to negligible for borehole diameters up to 12 1/4 inches and mud resistivities as low as .02 ohm meter.
It has been reported that an MWD focused current type of device will provide more immunity to borehole effects when mud resistivity is very low than will an electromagnetic wave sensor. A comparison between the response of the improved electromagnetic wave sensor, that of an MWD focused-current resistivity sensor and of a lateral type of sensor demonstrates that this need not be the case. Finally, a logging example is presented in which the improved and original electromagnetic wave sensor responses are compared. This example also confirms the relative insensitivity of the improved propagating electromagnetic wave sensor to borehole effects.
Drawdown Well Test Analysis for Multicomponent Hydrocarbon Systems
Authors: Thompson L. G. , Vo D. T. 
Published: December 2007

ABSTRACT
Drawdown pressure and phase rate data from retrograde condensate reservoirs are analyzed to obtain estimates of individual phase molar composition, phase effective permeability and sandface saturation as functions of wellbore pressure (or total flowing time). The results of the latter two calculations are combined to construct an effective permeability/phase saturation relationship which reflects the in situ reservoir flowing conditions. Data from reservoirs which are damaged, undamaged, stimulated, and for which the initial reservoir pressure is close to the dewpoint pressure are considered.
Methods of estimating reservoir absolute permeability and skin factor from measured drawdown pressure/sandface phase rates and known initial reservoir fluid composition are also presented. These methods do not presume availability of relative permeability curves, and as such should enjoy greater ease of applicability to field data analysis than presently available methods.
Prediction of Geochemical Formation Damage in the Vicksburg Formation of South Texas
Authors: Riese W. C. , Riese A. C. 
Published: December 2007

ABSTRACT
Formation damage is broadly considered to be the occlusion of pore throats by debris. This occlusion is generally thought to result from the introduction of fine-grained particles to the formation, or the migration of particles already present in the formation. We contend, however, that particles and cements may be precipitated in situ by disruption of geochemical equilibrium in the reservoir.
The Olivarez #2 well was completed in the Oligocene Vicksburg Formation (Z-sand), using a KCI-based completion fluid and was traced using a fluid of similar composition. The well began to unload and flow immediately and was killed using 14ppg CaBr2. Some damage was suspected to have occurred at this point because the initial production tests did not see flow rates comparable to other wells in the field. A second frac of the formation was then undertaken using CaCl2/CaBr2-based fluids, but no significant improvement in flow rates was realized.
Our analysis of this problem focused on rigorous geochemical modeling of the reservoir and the changes that would be induced if fluids were added to the reservoir fluid-rock system. Calculations accounted for activity coefficients via the extended Debye-Huckel relationship and for elevated temperatures by the van't Hoff or Kirchoff equations. Geochemical analysis of reservoir environments utilizing these equations yields a more accurate picture than can be reached using Stiff-Davis or similar approaches. Consideration of sulfates, carbonates, and silicates concurrently is also only possible with this type of analysis.
The results of our modeling indicate that the loss of KCI-based completion fluids to the formation may have resulted in the precipitation of both carbonate and silicate phases within the formation. Subsequent attempts to improve deliverability by tracing produced no improvement because the loss of CaCl2- and CaBr2-bearing fluids to the formation during kill and tracing procedures apparently caused additional silicate-phase precipitation.
We recommend geochemical reservoir characterization as a critical part of proper reservoir management. Such work, when done in a timely fashion, can help predict the tendency of a reservoir system to produce irreparable precipitate damage. This type of work may also help curtail the use of costly clean-up or stimulation procedures where the geochemistry of the system will render them ineffective.
A Direct Deconvolution or Convolution Algorithm for Well Test Analysis
Authors: Roumboutsos A. , Stewart G. 
Published: December 2007

ABSTRACTA numerical Laplace Transformation based on a piecewiзe linear approximation to a function has been developed. The convolution of fundamental pressure and flow transforms yields variable rate pressure responses. The deconvolution process involving the quotient of transforms allows the equivalent constant rate response to be determined from measured pressure and rate data. This provides a general basis for the treatment of variable rate well tests in heterogeneous systems. The inversion of products or quotients of Laplace transforms is carried out by numerical inversion algorithms, usually the fast method due to Stehfest. The application of deconvolution to buildup tests is considered. Synthetic and field examples are used to illustrate the application of the techniques.
"Reservoir Description: A Practical Synergistic Engineering and Geological Approach Based on Analysis of Core Data"
Authors: Amaefule J. O. , Kersey D. G. , Marschall D. M. , Powell J. D. , Valencia L. E. , Keelan D. K. 
Published: December 2007

ABSTRACT
Description of reservoir rocks in terms of complex variations in hydraulic properties, heterogeneity and geometry requires a synergistic, multidisciplinary engineering and geological approach.
This paper presents a practical systematic approach to integration of various core analysis data for reservoir description. Various petrophysicai parameters are strongly correlated with pore space attributes using the mean hydraulic radius, K/∅. Additionally, empirical equations are presented for transforming lab-derived core properties to appropriate reservoir in-situ stress conditions.