bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Rock-Pore Characteristics on Oil Recovery at Breakthrough and Ultimate Oil Recovery in Water-Wet Sandstones
Authors: Owolabi O. O. , Watson R. W. 
Published: December 2007

ABSTRACT
The effects of rock/pore characteristics such as porosity, permeability, tortuosity, formation factor, wettability index, irreducible water saturation, and mercury porosimetry properties, on oil recovery (at breakthrough and floodout) have been investigated in linearcores. Berea sandstone cores were placed in horizontal position with their flood planes parallel to their bedding planes and oil displaced from them by brine at injection rate ranging from 1.20 cc/min to 7.90 cc/min. A scaling-coefficient (product of core length in cm, water velocity in cm/min and water viscosity in cp) of about 5.0 was maintained in each of the waterfloods.
A 10 cp (at 35°C) binary mixture of refined oils, and twenty-one sandstone linear-cores ranging in length from 7.3 to 52.1 cm and diameter ranging from 3.79 to 3.88 cm were used for the study. For the waterfloods, the investigation was conducted at a temperature of 35°C and confining pressure of 500 psi. Six to fifty-four core plugs were extracted from each of the waterflooded cores for a total of 580 core plugs. The core plugs were further analyzed by conducting wettability and mercury porosimetry tests.
The results of the tests show that the core samples investigated were all water-wet and they all exhibited steep-concave unimodal pore-size distribution. Furthermore, the results show good correlations between waterflood sandstone oil recovery (at breakthrough and floodout) and porosity, permeability, formation factor, irreducible water saturation, pore intrusion volume, pore surface area, pore specific surface area, apparent (skeletal) density and mercury recovery efficiency. The accuracy of the oil recovery predictions by these newly proposed empirical models show encouraging results.
Performance Evaluation of Waterflood Project in Southern West Virginia
Authors: Mohaghegh Shahab , Samuel Ameri , Aminian Khashayar , Chatterjee Ujjal 
Published: December 2007

ABSTRACT
Granny Creek oil field is located in Southern West Virginia in the Appalachian Basin. It has been producing from the Big Injun formation. Primary production was initiated in the 1920's and continued until early 1970's. Around the mid 70's, new wells were drilled and a waterflood project was started which is still in progress. During the course of the waterflood project, some problems were encountered. These problems included, inconsistency in sweep efficiency in adjacent patterns, and high injection pressure.
In this field often two adjacent five spot patterns with similar injection to pore volume ratios exhibit totally different oil and water production rates. While water does not breakthrough in some patterns for months, other patterns experience instantaneous water breakthrough. Unusually high injection pressure is observed almost throughout the field, and yet some injection wells exhibit normal injection pressures.
Presented in this paper is a summary of approaches, methodologies, results and conclusions that have been reached during the performance evaluation of this waterflood project. With the aid of reservoir simulation studies, some major heterogeneities were characterized and modeled for this field. Interpretations of seismic studies were used to confirm the orientation of such heterogeneities in the field.
Characterization of a Complex Reservoir in West Virginia
Authors: Aminian Khashayar 
Published: December 2007

ABSTRACT
Reservoir characterization plays a significant role in economic success of the reservoir management. Nearly all reservoirs show some degree of heterogeneity which invariably impacts production. As a result, the production performance of a complex reservoir cannot be realistically predicted without accurate reservoir characterization. Reservoir characterization is a complex problem which requires integration and interpretation of various geological and engineering information.
A systematic and synergistic approach has been employed in this study for characterization of an oil reservoir in West Virginia. Stratigraphy, structural, and seismic data have been utilized to develop a model of the reservoir. Significant amount of reservoir data were collected, compiled and analyzed. Innovative approaches were employed to integrated and reconcile thin-section and scanning-electron microscopy results, petrographic data, initial production data, core analysis, pressure transient tests, and well log interpretation results to quantify model parameters. Primary and secondary production data have been utilized to evaluate and modify the model and its attributes. The results indicated the existence of major heterogeneities in the reservoir which have had profound impact on the performance of the reservoir.
Viscous and Degradation Properties of Crosslinked HPG Gels: Some Laboratory Observations
Authors: Fan Yong , Holditch S. A. 
Published: December 2007

Abstract
Measuring the viscosity of fracturing fluids is important to designing and supervising a fracture treatment. Viscosity is a critical parameter used to compute fracture dimensions and estimate proppant transport. Accurate knowledge of the viscous properties of crosslinked gels is also indispensable for laboratory evaluation of potential fracturing fluid systems. However, attempts to reliably measure the viscous properties of crosslinked gels have proven difficult because of the complex nature of the fluids. Studies by Prud'homme el al.1,2 have demonstrated that viscous properties of crosslinked HPG polymers are controlled by the gel network structure that is formed during crosslinking. The gel network structure is determined by chemical reaction kinetics and process conditions in which the reaction proceeds. The crosslinking reaction causes the gel to be a viscoelastic fluid. As such, temperature and shear histories, crosslinker type, solution pH, degree of hydration of the HPG solution as well as test duration can have a profound effect on the viscous properties of crosslinked HPG gels. Detailed rheological characterization of a crosslinked fracturing fluid remains a difficult and elusive challenge.3,4
Generally, both steady shear and dynamic oscillatory measurements are required to describe the viscoelastic behavior of a crosslinked gel. In a dynamic test, a sinusoidal movement is imposed on the system that results in measurements of storage modulus, G′, and the loss modulus, G″. These parameters provide information about fluid elasticity and energy dissipation and can be used to determine the gel structure and evolution of structure.5,6
In steady shear, shear stress as a function of shear rate is measured, then the viscosity is calculated. Viscosity is important to the design of a fracturing treatment. To generate meaningful viscosity data, the experiment should be conducted at conditions that represent the actual fracturing treatment. Proposed test techniques require dynamic crosslinker injection, continuous shear during gelation, plus controlled temperature and shear rate histories during the measurements.7
The rheology research laboratory at Texas A&M University is equipped with a standard industry Fann 50 viscometer, in addition to the GRI/TAMU rheology flow loop. Both are capable of measuring the steady-shear viscous behavior of complex gel under simulated fracture conditions. The unique aspect of the laboratory is that different types of viscometers have been linked together in a continuous flow loop. As such, it is possible to run simultaneous tests using identical gel formulations, mixing procedures and shear rates with different geometry viscometers. The following text will briefly discuss the equipment; detailed information can be found in the literature.8-10
Crude Oil Fingerprinting by the Total Scanning Fluorescence Technique
Authors: Reyes M. V. 
Published: December 2007

EXTENDED ABSTRACT
Texaco's Exploration and Production Technology (EPTD) Division has been developing a crude oil identification method to improve surface logging techniques (formerly known as mud logging). Mudlogging is a commercial service designed to locate with respect to depth the occurrences of hydrocarbons in a well while drilling.
Order No. 636: The Evolution of an Industry
Authors: Mullen Mary , Rich R. S. 
Published: December 2007

ABSTRACT
The implementation of Federal Energy Regulatory Commission ("FERC") Order No. 636 will result in major changes in the operations of interstate natural gas pipelines and the way natural gas is bought, sold, and transported. Instead of a "bundled" service for which the customer pays one price for gas, transportation, storage and related services, interstate pipelines will offer a menu of services from which customers can choose.
This paper discusses the major changes brought about by Order No. 636 and focuses on the "unbundling" of interstate pipeline services and the resulting operational changes, the development of market centers, and the role of storage in this new environment.
Drilling Optimization of an Oil or Gas Field
Authors: Rampersad Paul , Hareland Geir , Pairintra Thamarat 
Published: December 2007

ABSTRACT
This paper demonstrates how information obtained while drilling an oil or gas well, is utilized to optimize drilling costs for upcoming wells in the same field by creating a Geological Drilling Log (GDL). The GDL is created by using drilling models specific to the bits used for individual intervals to generate a formation profile of properties for the entire section drilled on a foot by foot basis. The simulation and optimization is used in the field with the GDL to properly select bits (Tricone or Natural Diamond) and operating conditions for the lowest cost per foot.
The concept of a learning curve is utilized by conducting a number of simulations using the GDL, so that the optimum drilling parameters and conditions are eventually obtained. The approach to drilling optimization using a simulator and a GDL in this study showed a substantial reduction in drilling cost. The drilling models used in this study are capable of accurately simulating the drilling of a well and reproducing realistic Rates of Penetration (ROP).
Comparison and Verification of Two Models which Predict Minimum Principal In-Situ Stress from Triaxiai Data
Authors: Hareland G. , Harikrishnan R. , Warpinski N. R. 
Published: December 2007

ABSTRACT
This paper evaluates the correlation between values of minimum principal in situ stress derived from two different models which use data obtained from triaxiai core tests and coefficient for earth at rest correlations. Both models use triaxiai laboratory tests with different confining pressures. The first method uses a verified fit to the Moor failure envelope as a function of average rock grain size, which was obtained from detailed microscopic analyses. The second method uses the Mohr-Couiomb failure criterion. Both approaches give an angle of internal friction which is used to calculate the coefficient for earth at rest which gives the minimum principal in situ stress. The minimum principal in situ stress is then compared to actual field mini-frac test data which accurately determine the minimum principal in situ stress and are used to verify the accuracy of the correlations. The cores and the mini-frac stress test were obtained from two wells, the Gas Research Institute's (GRI's) Staged Field Experiment (SFE) #1 well through the Travis Peak Formation in the East Texas Basin, and the Department of Energy's (DOE's) Multiwell Experiment (MWX) wells located west-southwest of the town of Rifle, Colorado, near the Rulison gas field. Results from this study indicate that the calculated minimum principal in situ stress values obtained by utilizing the rock failure envelope as a function of average rock grain size correlation are in better agreement with the measured stress values ( from mini-frac tests) than those obtained by utilizing the Mohr-Couiomb failure criterion.
The Effect of Rotational Speed and Eccentricity on Annular Flows with Application to Slim Hole Drilling Hydraulics
Authors: Ribeiro P. R. , Podio A. L. , Sepehmoori K. 
Published: December 2007

ABSTRACT
One of the major issues in slim-hole drilling and coring operations is the accurate prediction of pressure losses in the annulus, in order to guarantee optimum operating conditions. As has been pointed out in the literature, the small annular clearance and the high rotational speeds of the drillstring are factors which preclude the common assumption of unidimensional axial flow in the annulus, which has commonly been applied for conventional pressure drop computations.
In order to address the effect of rotational speed and eccentricity of the inner core in the laminar flow of power law fluids in the annulus, a finite element scheme was applied. The numerical model showed good agreement with available laboratory data for axial-rotary flows in concentric annuli and axial flows in an eccentric annulus. The analysis revealed the significant effect that the rotational speed and eccentricity of the inner cylinder have on the pressure loss of flows through the annulus.
Flow in Porous Media
Authors: Baigorria R. , Pousa J. L. , Di Leo F. , Marañon J. 
Published: December 2007

Abstract
The aim of this paper is to review the numerical simulation methods now being used for dealing with fluid displacement in porous media. One of them is the invasion percolation method, IP, which applies where capillary forces are dominant with respect to viscous forces at the fluid interface. The diffusion-limited agregation method, DLA, consists in the construction of an aggregate of particles from a single particle, the seed, with the restrictions imposed by a probability field gradient satisfying the Laplace equation. Finally, the method of stochastic capillary networks takes advantage of the analogy between the displacement of a fluid in a porous medium and the circulation of the electric current in a purely resistive circuit. A flow problem in a porous medium is said to be solved when analytical expressions relating the pressure and the velocity fields are obtained. From this viewpoint the IP method and the DLA method do not provide this kind of information, although the latter describes the behaviour of the fluids at the interface correctly. The method of stochastic networks, on the other hand, do provide both pressure and velocity fields through the simulation process itself. These fields enable one to calculate flow rates at the inlet and oulet faces of the network as well as inside it, so making it possible to match numerical and experimental results. These methods are mainly applied to assisted and secondary oil recovery as well as in the contamination of aquifers. In particular, the method of stochastic networks is a valuable tool that constitutes a suitable complement to petrophysical and fluid mechanical laboratory measurements, which are of the utmost importance for the reservoir engineer.
Sweep Efficiency Estimates for Reservoirs with Nonuniform Layers
Authors: Araque-Martinez A. N. , Lake L. W. 
Published: December 2007

Abstract
We study a new vertical sweep efficiency correlation for reservoirs with non-uniform layers and compare the effect of permeability autocorrelation on these estimates. Vertical sweep efficiency correlations are important because, in spite of sophisticated numerical simulators now available, there still remains a need for rapid estimates of oil recovery. The vertical sweep efficiencies are calculated using the chemical flooding simulator UTCHEM for a two-dimensional vertical cross-section with one injector and one producer, both also vertical.
As measures of heterogeneity we use the Dykstra-Parsons coefficient (VDP) in the case of a strictly layered reservoir and the Gelhar-Axness coefficient (HI) in the case of a nonlayered reservoir. We validate a strictly layered case and predict the vertical sweep efficiency in cases with nonuniform layers. We show that for mobility ratios greater than one, the effluent concentration of the injected fluid (in this case, polymer) oscillates because of viscous instability.
For unlayered cross sections, we show that the Gelhar-Axness coefficient is a better vertical sweep efficiency estimator than the Dykstra-Parsons coefficient, because it accounts for spatial correlation (autocorrelation) as well as for heterogeneity. The vertical sweep efficiency decreases as we increase HI for the same VDP.
Mud Cake Compressibility and Mobility of Fluid Loss Evaluation
Authors: Tovar J. G. , Martinez A. , Bockh A. , Ford M. 
Published: December 2007

Abstract
Presently, the mud cake and the filtration of the mud are evaluated under qualitative criteria, using API rules. In this paper, a novel method is introduced to determine the consistency and the mobility of the fluids through the cake. A study was conducted both statically and dynamically in the lab to determine the effect of the mud components and contaminants. Some field applications are presented.
The Effect of Wettability on Two-Phase Flow
Authors: Calvo A. L. , Chertcoff R. H. , Cachile M. A. , Rosen M. , Cena N. H. 
Published: December 2007

ABSTRACT
Wettability variations during the exchange of wetting and non-wetting fluids flowing in a solid porous medium are essential effects in enhanced oil recovery. However it is difficult to analyze wettability effects in real porous media due to the difficulty of controlling surface states as well as to their complex internal geometries. A first important step then is to study the basic interplay between viscous and capillary effects occurring during the motion of an interface meniscus in a single pore.
We present here an experimental study of diphasic flows in capillary tubes with millimeter size diameters in which we have determined dynamically the capillary pressure variations during the motion of an interface in a such a restricted geometry. We have chosen to analyze the variations of the capillary pressure rather than those of the contact angle θ. As for classical ndiphasic flow measurements in porous rocks, we have studied imbibition and drainage flows. Finally, the thickness of the wetting film remaining on the tube wall during the drainage flow is studied experimentally. An original radiotracers technique was developed and the film thickness is measured as a function of the capillary number.
At the same time, using a visualization technique, the stability of the wetting-water film is studied. Original results have been found showing that final instability configuration (drops, rings and bridges) depends on capillary number.
Wettability and its effects on the distribution of water and oil in a reservoir are highly complex phenomena which often are not properly understood. This work is intended to describe some of the physics of the capillary effects on that distribution.
Prediction of CO2 Minimum Miscibility Pressures
Authors: Ahmed T. H. 
Published: December 2007

ABSTRACT
This paper presents a practical approach for predicting the Minimum Miscibiiity Pressure (MMP) required for the multi-contact miscible displacement of crude oil systems by CO2. The technique is based on applying the modified Peng and Robinson Equation of State (PREOS) in conjunction with a newly introduced "Miscibiiity Function." The miscibiiity function is designed to provide accurate predictions of the MMP. It is the objective of this paper to demonstrate how this miscibiiity function can be used to determine the necessary conditions required for miscible displacement of hydrocarbon system by CO2. The validity and the use of the proposed approach is illustrated by matching several minimum miscibiiity pressure values as determined from experimental slim-tube displacement data.
Applying Expert Systems in Heavy/Extra Heavy Oil Production Operations
Authors: Reina M. 
Published: December 2007

ABSTRACT
Expert Systems (ES) have been widely used in the oil industry. They are capable of giving opportune responses for the decision making, even for the inexperienced in any given field. In Corpoven S.A. (an affiliate of PDVSA), ES have been developed for drilling operations, production, refining, human resources, field maintenance, etc. In this paper, the results of the implementation of an ES in the production of heavy/extra heavy oil fields by cyclic steam injection are discussed. This is a modular system, that can be installed in a PC, which has been in use since 1990 with excellent results.
This ES, called SEIAV (Sistema Experto en Inyecciôn Alterna de Vapor), covers all the activities related to the exploitation of any heavy/extra heavy oil field. The system works from selecting the candidate well for steaming up until the well is put on production. It monitors the whole operation, detecting and suggesting solutions to any anomaly.
The SEIAV have been used with excellent results in the automatic selection of candidate wells for steaming, as well as in detecting anomalies during the steam injection and hot production operations.
3D Seismic and Horizontal Drilling - A Case History, Bodo, Alberta
Authors: Howell E. C. , Stacey E. C. 
Published: December 2007

ABSTRACT
The McLaren sandstone is a Lower Cretaceous fluvial channel complex located in southeastern part of the province of Alberta, Canada. The South Bodo Field produces heavy gravity oil from this formation, but volumes are increased by the use of horizontal drilling. The McLaren sandstone ranges in thickness to a maximum of 36 m. The reservoir contains a gas cap, a heavy oil and a water leg with porosities of approximately 30% and permeabilities of 2-3d. Due to the large velocity contrast between the channel and the surrounding rock, the McLaren channel complex is well defined seismically. In 1992, a 3D seismic program was shot over the field comprising an area of 33.8 square kilometres. The 3D program gave the additional resolution necessary to accurately locate the horizontal wells.
Several interpreted maps showing the structure on the reservoir and seismic amplitude on the McLaren were used to locate the 15 horizontal wells drilled into the channel. The 3D data set has been inverted using the Generalized Linear Inversion techniques to obtain a velocity log over the zone of interest. Also, an AVO (Amplitude Versus Offset) study will predict the presence of gas in the reservoir from the bin gathers. These techniques may further define the reservoir limits in addition to conventional methods of mapping the structure.
A summary of the drilling results along with the logging and drilling technologies used in this project are reviewed. Reservoir simulation studies will be conducted for future drilling to investigate the gas and water coning properties of the channel sands. Minimum distances above the oil/water and below the gas/oil contacts will be determined from these studies to avoid coning of the gas and water. The MWD tool (Measure While Drilling) and hot wire gas detectors were used to help guide along the correct trajectory
In conclusion, the South Bodo Field represents an integration of technologies to optimize the production from a previously depleted field.
Environmental Issues in Oil and Gas Development in Malaysia
Authors: Evans D. B. , Yong E. F. 
Published: December 2007

Abstract
This paper presents an overall view of the environmental issues associated with oil and gas developments in Malaysia with particular emphasis on offshore platform developments, their associated pipelines and onshore processing facilities. The issues discussed include Malaysian Legislation and requirements for Environmental Impact Assessments, atmospheric emissions, aqueous emissions, waste disposal, wastewater and produced water treatment and discharge, noise, and chemicals usage.