bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tertiary Oil Recovery Economics in Louisiana
Authors: McCarthy Danny W. , Groat Chip , Chen Jan-Ku , Liau Tai-Ho , Weaver Robert E. C. , Aldahir A. S. 
Published: December 2007

ABSTRACT
This paper assembles the relevant economics for the production of tertiary oil in prototype Louisiana situations. The production techniques examined and compared include carbon dioxide flooding, in-situ combustion, steam injection, and micellar/polymer flooding.
A complete cost analysis is constructed for each EOR technique based specifically on reservoir properties with relevance to Louisiana.
Environmental Risks Associated with the Commercialization of Enhanced Oil Recovery
Authors: Riedel Ernest F. , Garrell Martin H. , Kaplan Edward , Sathaye Jayant , Bierman George R. 
Published: December 2007

ABSTRACT
A workshop sponsored by the United States Department of Energy Technology Assessment Division was held during August 1980 to discuss Enhanced Oil Recovery (EOR) production and associated environmental risks. The participants represented industry, government, environmental and private consulting groups.
The information collected at the workshop will be used in a DOE research project to identify and evaluate potential environmental, health and safety (E,H&S) concerns associated with the production of petroleum by enhanced oil recovery. This project is part of a continuing DOE program to assure that E,H&S concerns are addressed in a timely and cost-effective manner in energy technology development programs. This paper presents highlights of the workshop proceedings that may be of general interest to other researchers, the oil and gas industry and government agencies. The views presented in general represent a consensus of the workshop, but they do not necessarily represent the opinions of individual workshop participants, the authors, the Department of Energy or the National Laboratories.
A long list of potential environmental concerns were identified in the workshop. Only a few were felt to be potentially important: air quality, liquid waste injection, and worker health and safety considerations. Scenarios for EOR production were also reviewed and critiqued. An accurate production scenario will be required to characterize the magnitude and extent of potential E,H&S concerns from EOR production. Impediments to rapid expansion of EOR, such as lack of reservoir data, technological constraints, and economics and institutional considerations (e.g., windfall profits tax) were discussed. Accurate predictions of future EOR production levels were found to be difficult because of uncertainties in the numerous variables that might have major impacts on these levels. The potentially most significant environmental issue was found to be solid waste disposal and potential problems resulting from enforcement of the new Underground Injection Control Regulations. It was generally concluded that EOR is an environmentally safe form of increased fossil energy.
Mechanical Behavior of Mesaverde Shale and Sandstone at High Pressure
Authors: Lin Wunan 
Published: December 2007

ABSTRACT
Prediction of the effects of hydraulic fracturing for the stimulation of fluid recovery from low permeability rocks requires a fracture model and certain mechanical properties for input to the calculation codes. For such a study on the Western tight-gas-sands, we report here new rock mechanics measurements taken on Mesaverde shale (source rock) and sandstone (reservoir rock) from about 350-m depth (Colorado) and 1600-m depth (Wyoming). For each sandstone and shale, we have determined:
Tensile strength parallel and perpendicular to bedding, 0.1-MPa pressure. Triaxial stress failure envelope in compression to 300-MPa confining pressure, parallel and perpendicular to bedding, Pressure-volume behavior to 1.2 GPa.
The results for (1) indicate that, in. general, the tensile strength of Wyoming sandstone is about three times that of Colorado sandstone. For both sandstones, the tensile strength is isotropic with respect to bedding. The tensile strength of both shales parallel to bedding is about 30-50% greater than that measured normal to bedding. The shale from Wyoming has a tensile stength about 25-50% greater than that from Colorado.
Strengths and failure modes in compression (2) show that the transition between brittle failure and ductile deformation occurs at a confining pressure of about 0.1 GPa for the Colorado sandstone and, 0.25 GPa for all other rocks tested. No significant anisotropy in compressive strength is observed for these rocks except the Colorado shale. Colorado shale has about 40-50% strength anisotropy with loading perpendicular to bedding stronger than that parallel to bedding. However, the inhomogeneity of this rock may affect the measured strength anisotropy. The relative strengths of these rocks are shown in the following statements. In Colorado, the shale is about 50-70% stronger than the sandstone; in Wyoming, the shale is about 20-30% stronger than the sandstone. The Wyoming sandstone is about 50% stronger than that from Colorado; the Wyoming shale is about 20-30% stronger than that from Colorado.
Pressure-volume (3) loading indicates that - ΔV/V0 at 1.2 GPa for the sandstone from Colorado is about 6-7%; for the other rocks tested, about 3-4%. Bulk compressibility of these rocks as a function of pressure is calculated from the pressure-volume data.
Fracture Optimization in A Tight Gas Play: Muddy "J" Formation, Wattenberg Field, Colorado
Authors: Roberts C. N. 
Published: December 2007

ABSTRACT
Hydraulic fracturing has been performed in the tight gas sand of the Muddy "J" formation in Wattenberg Field since commercial production began in 1971. This study was made to determine the effectiveness of the different stimulation techniques which have evolved in an effort to optimize a procedure for the field. This paper discusses the development and results of this fracture-optimization program for the Wattenberg Field.
Well properties for the analysis were determined from logs, core samples, production data, fracture azimuths, mechanical property logs, and pressure transient data. Fracture treatments were studied by comparing: fluid type and quantity; proppant size, type, concentration, and quantities; and treating rate and pressure. Computer simulation of the induced fracture was correlated with type-curve analysis and actual performance to model the well. Stimulation success was based on economics, well performance, increased reserves, drainage area, and treating fluid efficiency.
Impact of a Disability Management Program (DMP) in a Fortune 100 Petrochemical Company
Authors: Bhojani F. , Tsai S. P. , Donnelly R. P. 
Published: December 2007

Abstract

Background
In an attempt to reduce non-occupational absences at a petrochemical corporation, an in-house disability management program was initiated.

Methods
An internet-based management tool was used by employees who were required to report all absences on the first day and again on the fourth workday absent. A medical certification form was required for absences of 4 or more working days.

Results
The program resulted in a 10% reduction in total absence days per employee (6.9 to 6.2) in 2003 compared to the previous year, while business units not utilizing the program had an 8% increase (5.5 to 5.9). This disability management program resulted in a more than 4 to 1 return on investment based on direct expenditures and cost savings in terms of reduced absence days, after one year implementation of the program. In addition, the disability management program continues to meet its objective of reducing disability related absenteeism by managing intermediate term absences (i.e. those lasting 4 days to 6 months). The average workdays missed due to illness among refinery workers reduced from 4.6 to 4.4 days per employees between 2002 and 2004.

Conclusions
The in-house disability management program successfully reduced absence duration, increased employee satisfaction and returned on the initial investment.
Status Report on Fracturing of Deep And Low Permeable Formations in West Germany
Authors: Brinkmann Friedrich W. 
Published: December 2007

ABSTRACT
The demand/supply situation in the European gas market led to an extensive effort to develop tight gas reservoirs in West Germany. Geological interpretation including all aspects of petrographical and petrophysical data were taken into account when the stimulation campaign on deep and tight Carboniferous reservoirs was started in 1977.
Thorough analyses on reservoir parameters including mineral contents and substantial compaction effects were used for detailed job design. The Carboniferous reservoirs, characterized by porosities of 8 - 12 %, permeabilities of 10 microdarcies to 1 md*, reservoir depth of more than 4000 m (13120 ft) and net thickness of 20 m (66 ft) can only be produced if MHF treatments of some 500 - 1000 m3 (3150 - 6300 bbl) of fluids and 100 - 200 t (2.2 - 4.4 million lbs) of highstrength proppants are applied. Special provisions have to be made with respect to casing design because salt sections and underpressured sour gas reservoirs have to be penetrated before the wells encounter the tight gas sands. In order to find out optimum job design, various oil base and water base frac fluids and various types of high strength proppants were tested in several MHF stimulation treatments. The success of several jobs was demonstrated by both cased-hole logs and production performance evaluation. The production histories of the stimulated wells and the economic evaluation at various conditions prove that MHF treatments can be justified since there is no other alternative to recover the presently known 20 × 109 m3 (0.7 TCF) of gas reserves in known structures and to produce about 100 × 109 m3 (3.5 TCF) of additional gas reserves which are expected from future exploration activities on Carboniferous in West Germany.
The conclusions which are drawn in this paper refer to 13 stimulation jobs out of 15 which have been executed in Europe, all of them in structures located in West Germany.
Evidence of Permeability Enhancement Through Cyclic Dry Gas Injection
Authors: Branagan Paul , Cotner Gene , Gettman Gregory 
Published: December 2007

ABSTRACT
The phenomenon of deliverability improvement due to the cycling of dry gas in storage reservoirs has been well documented at Colorado Interstate Gas Company's (a subsidiary of The Coastal Corporation) Fort Morgan storage field. Core data from nine original Fort Morgan wells indicated the initial permeability of the Dakota "D" storage reservoir averaged 187 md. After 15 years of cycling gas through the reservoir, the average permeability as determined from pressure buildup is in the one to ten Darcy range. Original open flow potentials averaged about 1 MMcfd, and is considered very conservative.
These indicated permeability and observed productivity improvements were greater than would be expected from the normal core derived relationship between relative permeability to gas and fluid saturation. This empirical experience also observed in other storage fields was the basis for the belief that other phenomena, such as the dehydration of matrix clays and the removal of "skin effects" such as high fluid saturation adjacent to induced fracture surfaces, also contribute to productivity improvement with cyclic dry gas injection.
Based on this experience of improvement in storage fields, Colorado Interstate Gas Company (CIG) and the U.S. Department of Energy (DOE), embarked on a field test to determine if cyclic dry gas injection could improve actual producing wells completed in the tight gas sands of the Dakota Muddy "J" in the Wattenberg field of Colorado. Two wells owned by Machii Ross were made available for use in the project. The project wells, Miller #1 and Sprague #1, located in the western portion of the Wattenberg field, are shown in Figure 1. The initial testing of the experimental wells was designed to provide base data concerning each of the wells, the hydraulic fracture, and the surrounding formation. This testing was then followed by a gas cycling period when the wells would alternately produce gas, have the gas dehydrated and then injected into the other well.
Fluid Loading in Low Permeability Gas Wells in the Cotton Valley Sands of East Texas
Authors: MacDonald Richard M. 
Published: December 2007

ABSTRACT
Fluid buildup in the wellbore has long been recognized as a detriment to flow from gas wells. This is particularly true for wells completed in formations with low permeability, where hydraulic fracture stimulation is a prerequisite to commercial production. In natural flow, the gas velocity governs whether the fluid produced into the wellbore will be conveyed to the surface or allowed to fall back on the formation. It is therefore of extreme importance that a method for predicting the minimum or critical velocity be established. Prediction methods previously documented in literature have proven inaccurate for the flow conditions encountered in Cotton Valley wells in the East Texas area. A modified calculation procedure, based on actual flow data, for the determination of fluid loading of said wells is presented. To sustain natural flow it is imperative the gas velocity be above the calculated critical value. A number of methods are available for increasing the gas velocity. The effects of tubing size and wellhead pressure as they pertain to gas velocity are presented.
Prop Transport in a Large Vertical Model
Authors: Sievert John A. , Wahl Harry A. , Clark Peter E. , Harkin Michael W. 
Published: December 2007

ABSTRACT
A large vertical-slot model without fluid loss was used to evaluate the roles of fluid type, fluid viscosity, prop concentration and flow rate on prop transport and pack growth. Individual particle trajectories as well as overall pack growth were measured.
With non-Newtonian fluids, changes in either prop concentration or gel concentration (viscosity) produced significant changes in pack growth. By contrast, a 0.03-Pa·s (30-cp) Newtonian fluid system allowed the prop to settle so rapidly that no influence due to the variables of interest could be detected. A 0.06-Pa·s (60-cp) Newtonian system showed a flow rate effect when the prop concentration was held constant.
Observations made during the experiments indicate that some forces present in the gelled system were absent from the Newtonian system. Measured pack growth rates do not agree with those calculated by substituting measured particle fall rates into existing mathematical models. This is true for both Newtonian and non-Newtonian fluids. Much work remains to be done before prop transport and deposition in vertical slots is adequately understood.
Embedment of High Strength Proppant into Low-Permeability Reservoir Rock
Authors: Volk Leonard J. , Raible Clarence J. , Carroll Herbert B. , Spears Judy S. 
Published: December 2007

ABSTRACT
Embedment of sintered bauxite into Berea, sandstone core, and shale core at closure pressures up to 10,000 psi (69 MPa) is reported. Several variables influencing fracture closure are examined: closure pressure, proppant size and size distribution, proppant concentration (up to a monolayer), formation hardness and surface roughness. Comparison is made with sand proppant. Empirical equations are derived to describe embedment into sandstones and shale for non-crushing proppants such as sintered bauxite.
New Proppants for Deep Gas Well Stimulation
Authors: Cutler Raymond A. , Jones Arfon H. , Swanson Stephen R. , Carroll Herbert B. 
Published: December 2007

ABSTRACT
Existing high strength proppants have desirable strength characteristics for propping deep hydraulic fractures, but also have high specific gravities and high cost when compared to sand. A low specific gravity proppant would reduce costs and improve fracture control.
Theoretical stress and strength analyses suggest that porous and hollow ceramics offer an alternative to dense proppants. Fracture conductivity as a function of closure pressure was experimentally determined for several materials. Good correlation of experimental results with theory was observed for solid and porous proppants.
Fabrication methods for the production of inexpensive lightweight proppants are discussed. Spray drying into a fluidized bed appears to be a viable method for producing both porous and hollow proppants. Characterization of spray dried proppants is discussed as well as materials which may be effective lightweight proppants. Areas of emphasis for future research are discussed.
Recovery of Heat and Carbon Dioxide from Compressor Station Exhaust Gas
Authors: Fang Cheng-Shen , Garber James Daniel , Farshad Fred F. , Broadhurst Robert C. 
Published: December 2007

Abstract
Gas compressor flue gas has sufficient heat content that heat recovery is practical. Steam and electrical power can be generated in this manner which reduces the utility cost of removing carbon dioxide from the flue gas.
A survey of various methods of removing carbon dioxide from flue gas has shown that monoethanolamine (MEA) is the best chemical absorbent at the low pressures available for this process.
A system has been designed to compress, dehydrate, and transport carbon dioxide to the receiving oil reservoir which could be 10 or 100 miles away from the available source.
Pressure and Temperature Dependent Properties of the Rock-Fluid Systems in Petroleum and Geothermal Formations
Authors: Ehlig-Economides Christine A. , Economides Michael J. 
Published: December 2007

ABSTRACT
A number of experimental studies have focused on the properties of the porous medium and the fluids contained therein at elevated pressures and temperatures. Rock properties which appear to be affected by the pressure and temperature levels include permeability, porosity, and compressibility. Single phase fluid properties of interest include viscosity, density, compressibility, and vapor pressure. Fundamental properties which govern the behavior of multiple phases include surface tension and wettability. Finally, two properties which are used to represent multiple fluid phase behavior in the porous medium are capillary pressure and relative permeability.
Methods exist for measuring rock properties for various rock types, bulk properties of single phase fluids, and the properties of multiple contacting phases as functions of pressure and temperatures. Capillary pressure curves and relative permeability data are then determined for reservoir conditions using additional experimental measurements and calculations based on the measured rock and fluid properties. However, certain experimental results suggest that the fluid and rock properties may be affected by the particular rock-fluid combination.
In this paper, experimental results from several major studies and the interpretations offered are examined in detail. Since the interpretation for one set of results have frequently been inconsistent with results of related experiments, a unified theory is sought.
Dynamic Modelling of Produced Water Reinjection in Depleted Naturally Fractured Gas Fields
Authors: Weijermans P. -J. , Warren G. 
Published: December 2007

Abstract
NAM in the Netherlands is currently conducting studies to redevelop the Schoonebeek oil field, onshore in the Netherlands. Steam flooding is the envisaged process.
Large volumes of produced water from this field are to be re-injected in regional depleted Zechstein fractured carbonate gas fields. Estimates of injection rates and volumes are required for reservoir selection and pumping requirements.
This paper demonstrates a methodology which permits injection rate and volume predictions to be made in a simple spreadsheet model based on historical measured gas production rates and volumes. The paper describes how to convert an analytical gas productivity index solution for dual-porosity systems to a water injectivity index. The conversion was validated using rigorous dual-porosity simulations and sensitised to a broad range of matrix and fracture properties. It was found that injectivity in the fractured Zechstein carbonate is constrained by the effective permeability of the fracture system and is relatively insensitive to matrix permeability and fracture spacing. This behavior was verified by calculation of a dual-porosity pseudo skin factor. Partially fractured models also demonstrate that some matrix pore space which was capable of producing gas, cannot be effectively accessed by injected water volumes.
The converted water injectivity index combined with other nonlinear repressurisation, relative permeability and water viscosity effects were combined with surface pump curve and wellbore head/friction calculations to construct a spreadsheet capable of predicting long term injectivity on an individual well basis. A large number of wells were screened and optimized using this practical tool.
This methodology can be readily applied to other water disposal projects targeting depleted, naturally fractured or matrix only gas fields.
A Stable Numerical Model for Vertically Fractured Gas Reservoir Incorporating Stress Sensitivity
Authors: Chen Shing-Ming , Evers John F. 
Published: December 2007

ABSTRACT
The transient pressure behavior of a vertically fractured reservoir has been solved successfully based on numerical solutions.1,2 These solutions enhance the understanding of early time portion during the drawdown or the build-up test conducted in a vertically fractured reservoir. To completely understand the performance of a gas reservoir, solutions for later time are also necessary. However, stability considerations always complicate the design of the model. The main objective of this work is to develop a numerical model which could be stable for all times.
The model is formulated for a fracture of limited and radial extent completely penetrating the producing formation vertically. The model equations are transformed using conformal mapping. Appropriate stability criteria are developed and the resulting finite difference equations are solved using the Iterative ADIP method. The boundary conditions are handled using a special numerical approach resulting in stable solutions for all times. Another feature of the developed procedure is the ability to handle finite fracture conductivity and stress sensitivity.