bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non-Darcy Flow Coefficients and Relative Permeabilities for Gas/Brine Systems
Authors: Civan F. , Evans R. D. 
Published: December 2007

ABSTRACT
A method for calculating the effective non-Darcy flow coefficient and relative permeabilities for gas/brine systems is presented. The capillary pressure is considered to account for the end-effect. This method is applicable to linear displacement in laboratory cores.
The computational model was developed by extending the Civan and Donaldson1 model to include the non-Darcy effect and interfacial drag between the gas and liquid phases. For this purpose Darcy’s law was replaced by the Forchheimer equation modified for two-phase systems by Tutu et al. (see Schulenberg and Muller2). Second, a pseudo-pressure formulation was carried out to transform the compressible gas flow and the slightly compressible brine flow equations to incompressible fluid type equations. This serves as a convenience in the calculations. Third, an input-output formulation of the model equations is facilitated for direct calculation of the non-Darcy factors and the relative permeabilities of the gas and the brine phases from the measurements of the pressure differential and the effluent gas to brine ratio. A detailed description of the calculation procedure for implementation on personal computers is presented. Also, the unsteady-state and steady-state differential formulations are developed for comparison purposes.
This method for the calculation of non—Darcy factors simultaneously with the relative permeabilities is essential for the analysis of gas reservoirs involving gas/brine systems. In particular, the simulation of water coning around vertical and horizontal wells where non-Darcy flow may be significant represents an important application of the results presented in this paper.
An Overview of an Instrumented Steam Injection Test Program
Authors: Traynor B. V. , Reid T. B. , Frazier T. R. , Brown V. R. 
Published: December 2007

ABSTRACT
The U.S. DUE has funded a program to "establish a body of valid heat loss data from an active steam injection well". This paper deals with the facilities, instrumentation and data systems required to develop wellbore heat loss information and the test results obtained.
Kawasaki Thermal Systems and Texaco have completed and instrumented a steam injection well in Kern River Field. A casing string instrumented to 800' has been completed. This string includes a total of 18 operational data channels providing temperature and heat flow information. In addition, a 1.9" logging string was attached to the casing as it was run and is used for temperature logs to a depth of 580'. Four instrumented steam injector completions will be operated during the test program.
Tests have been completed with the insulated Injection string. A total of 28 operational temperature and heat flow sensors provided data from this string.
A second instrumented completion, an uninsulated string with five thermocouples and two heat flux sensors has also been tested. These sensors together with the casing instrumentation provided data for this test.
These tests have established data which defines the heat transfer characteristics of the insulated and uninsulated completions. As the program is continued, the data will be utilized to validate a wellbore heat loss model, the final product of the program.
Field Results of Optimizing the Steam Foam Diversion Process in Cyclic Steam Applications
Authors: Cooke R. W. , Eson R. L. 
Published: December 2007

ABSTRACT
Steam foam diverters have been utilized to improve oil production in cyclic steaming applications since 1973. As reservoirs have aged and changed due to substantial oil production from both cyclic steaming and steam drive operations, the development of effective steam foam diversion treatment programs has become more complex.
This paper deals with the development of field application methods to optimize the effectiveness of cyclic steam foam diverters. Actual field results of the applications are described. Various foam diversion treatment methods are outline. Several steam foam diversion agents representing different types of chemical structures were utilized. The oil production responses are reported and the effects of changes in foam diverter type, quantity and method of application are correlated. The economic impact of various application methods, different materials and quantities are reported.
Prediction of Abnormal Pressures in the Niger Delta Basin Using Well Logs
Authors: Owolabi Olubunmi O. , Okpobiri Godwin A. , Obomanu Iyalla A. 
Published: December 2007

ABSTRACT
The hazard associated with abnormal formation pressures are of great concern to operating companies in the oil industry worldwide.
As an effort to alleviate mis problem in the Niger Delta, a spread of overpressures as they occur in the basin are shown in a map of the area. The table from which the map was produced contain the values of the top of overpressures obtained from shale resistivity, acoustic and resistivity plots against true vertical depth. The depth to the top of overpressures from the more than 230 wells studied, range from 6,500ft. along the shelf, to 15,000ft. at the middle belt and 16,000ft. at the west-belt of the Niger Delta Basin Complex.
Shale resistivity ratios and shale transit time differences obtained from normal and observed (abnormally high pressured) resistivities and transit times respectively, have been used in conjunction with the fluid pressure gradient, to generate the prediction curves. Comparison is made between the predicted formation pressures using the predicted curves and actual measured pressures. The standard deviation for the resistivity method is +0.626% psi/ft. (or about ±63 psi per 10,000ft.) and the acoustic method is ±2.058% psi/ft. (or about ±200 psi/ft. per 10,000ft.) Using data from previously published papers, correlating equations for predicting formation fluid pressure gradient are presented for some other major producing areas.
A Laboratory Study of Natural Gas Huff ‘N’ Puff
Authors: Haines Hiemi Kim , Monger Teresa G. 
Published: December 2007

Abstract
This paper examines the feasibility of cyclic natural gas injection for the enhanced recovery of light oil from waterflooded fields. Approximately 40 percent of water-flood residual oil was recovered in corefloods using two huff ‘n’ puff cycles at immiscible conditions. Gross gas utilizations were as low as 3 MSCF/STB. Response to cyclic injection contrasted favorably with immiscible WAG displacement. Coreflood results and numerical simulation indicated that incremental oil was not highly sensitive to remaining oil saturation. Predicted field recovery could be improved by managing offset wells. Response to cyclic gas injection was mostly dependent upon the amount of gas injected, suggesting that there will be a maximum economic slug size in field applications. Results indicated that repressurization and gas relative permeability hysteresis are the major oil recovery mechanisms.
A Robust Algorithm for Determining Hydrocarbon PVT Properties Using A Generalized Eos
Authors: Guehria Fawzi M. , Thompson Leslie G. , Reynolds Albert C. 
Published: December 2007

ABSTRACT
This paper presents and discusses a complete phase behavior package for determining PVT properties of mixtures of hydrocarbon and non-hydrocarbon species commonly encountered in the Petroleum Industry. All calculations are performed using a generalized Equation Of State, which upon selection of appropriate parameters, can be used to represent any of five Equations Of State commonly employed in the Petroleum Industry; i.e., Redlich - Kwong, Zudkevitch - Joffe - Redlich - Kwong, Soave - Redlich - Kwong, Peng - Robinson and Schmidt -Wenzel.
A robust algorithm, which utilizes a combination of the modified successive substitution and Minimum Variable Newton-Raphson methods, is used to calculate flash composition and saturation points. The algorithm is optimized to facilitate convergence near the critical point. The modified successive substitution method is used to determine the number of phases present at a given pressure and temperature. A new simple method is used to ascertain whether the system temperature is greater or less than the critical temperature. The method does not require estimation of the critical temperature for the specified mixture. Straight forward application of a method proposed by Baker and Luks allows the user to efficiently compute all saturation points (i.e., a bubble point and a dew point, or, an upper dew point and a lower dew point) at a given value of temperature. This latter unique feature enables the user to define the two-phase envelope without having to perform a multitude of time consuming flash calculations. Finally, results from our phase package are compared to those presented previously in the literature in order to verify the accuracy and efficiency of the computational procedure.
Benefits and Problems of Minifrac Applications in Coalbed Methane Wells
Authors: McDaniel B. W. 
Published: December 2007

Abstract
In conventional oil and gas reservoirs, the use of prefrac pump-in tests, in conjunction with analysis of the shut-in pressure response, has been a tremendous asset in Improving fracture stimulation designs. Since its introduction in 1979, many modifications and improved analysis techniques have evolved to increase the value of "minifrac" tests. In recent years, the popularity of completing wells in coal formations has led to the use of minifrac applications in these wells as operators attempt to better understand how coals respond to hydraulic fracturing. Although some operators have enjoyed success with minifracs, the usefulness of these types of prefrac tests has been limited as compared to applications in conventional gas reservoirs.
In fracture stimulation of coalbed methane wells, the use of minifrac tests and other pump-in tests has sometimes resulted in abnormally high injection pressures during the subsequent fracturing treatment. Many times the result has been an early screenout during the proppant placement. Some operators have abandoned the use of minifrac type pump-in tests for fear of creating pressure problems that would jeopardize the stimulation treatment.
In this paper, problems attributed to minifrac tests are described, along with explanations for many of these occurrences. Also included are successful applications of pump-in tests and a modification to improve fluid loss calculations. Recommended procedures to minimize the possibility of creating high Injection pressures are given. Field examples from the San Juan Basin, Piceance Basin, Black Warrior Basin and the Central Appalachian Basin are used to illustrate problems and support the recommended procedures presented.
Design Rules and Associated Spacer Properties for Optimal Mud Removal in Eccentric Annuli
Authors: Couturier M. , Guillot D. , Hendriks H. , Callet F. 
Published: December 2007

Abstract
Effective mud removal of drilling fluids from the wellbore is still a major problem in cementing. Although good pipe centralization has been known for years to be one of the keys to the success of the operation, most current design procedures do not allow pipe standoff to be taken into account.
When attempting to displace a mud in an eccentric annulus with a fluid thought to be in turbulent flow, it is shown that the displacing fluid can channel through the mud. An explanation for this phenomenon is given and a solution is proposed. When turbulent flow displacement cannot be achieved, displacement at lower rates has then to be considered and associated criteria leading then to improved mud removal efficiency are also discussed.
These displacement guidelines, as well as other more general considerations, show the need for spacers having well controlled engineering properties: compatibility, rheology, ability to suspend weighting agent, fluid loss. Examples of such spacers are presented and the properties of laboratory and field prepared samples are compared.1
Environmentally Safe Temporary Clay Stabilizer for Use in Well Service Fluids
Authors: Himes Ronald E. , Parker Mark A. , Schmeizl Eric G. 
Published: December 2007

ABSTRACT
The use of salts, such as potassium chloride (KCl) and sodium chloride (NaCl), as temporary clay stabilizers during oil well drilling, completions and servicing has been in practice for many years. Their effectiveness in this practice has been well established throughout the industry. However, because of the bulk and potential environmental hazards associated with the salts, many operators have begun to search out alternatives to their use.
Recent research has developed a relationship between physical properties of various cations (K+, Na+, etc.) and their efficiency as temporary clay stabilizers. These physical properties were then utilized to synthesize an organic cation with a higher efficiency as a clay stabilizer than the typical salts now used in the oil industry. This allows much lower salt concentrations to be used to obtain the same clay stabilizing effectiveness. The liquid product has proven to be much easier to handle and transport. It has been shown to be environmentally compatible and is biodegradable in its diluted form. Its effectiveness in fracturing operations has been extensively proven in numerous treatments in various formations throughout the U.S. and Canada.
Application of Rock Stress in Hydraulic Stimulation
Authors: Brevetti J. C. , Donaldson E. C. 
Published: December 2007

Abstract
Using a computer solution of the equilibrium fracture height model, fracture height growth out of the treated zone is simulated by comparison of the closure stress of the upper and lower boundaries with the closure stress of the pay zone.
Results from this model are compared to actual achieved fracture height measured from after-frac surveys on a diverse group of oil and gas wells. Pressure data are analyzed on a selected number of wells to demonstrate the effect of varying pore pressure on the model.
Utilizing this data, correlations between log-derived rock stress and fracture height growth are developed which will allow accurate prediction of total fracture height and containment pressures.
Economic Optimization of Fracture Stimulations Using Mixed Integer-Linear Programming
Authors: Thompson R. R. , Blumer D. J. 
Published: December 2007

Abstract
Determining an optimal fracture design can be a complex process, involving large amounts of computer and engineering time. This paper describes a method that utilizes mixed integer-linear programming to adjust a treatment's fluid selection, pump rate, proppant volume, and frac dimensions to arrive at an optimal design. This method can be readily adapted to most any fracture design model.
The optimization method presented in this paper has shown to be able to design less expensive fractures for a given stimulation ratio in less time than a trial and error approach. In the examples presented, variable stimulation costs (proppant, fluid, and hydraulic horsepower charges) were reduced by 50% compared to trial-and-error-derived designs.
An Analysis of Gravity-Dominated, Immiscible Flows in Dipping Reservoirs
Authors: Walsh M. P. , Moon G. M. 
Published: December 2007

Abstract
This work presents a fractional flow theory analysis of gravity-dominated, immiscible displacement in porous media. This effort represents the first to extend Buckley-Leverett theory to account for the effects of countercurrent flow while fluid injection and production is ongoing. The driving force for countercurrent flow is gravity, phase density differences, and a non-horizontal flow dimension. Our analysis is limited by the usual fractional flow theory assumptions, most importantly one-dimensional flow. Countercurrent flows are possible if the ratio of gravity to viscous forces forces is sufficiently large. Our analysis characterizes the gravity to viscous force ratio by a dimensionless Gravity Number. Our effort yields a more general and unified theory of immiscible displacement. We present new graphical solution methods to predict displacement performance for arbitrary initial and injected conditions.
Field Applications of Interwell Tracers for Reservoir Characterization of Enhanced Oil Recovery Pilot Areas
Authors: Lichtenberger G. J. 
Published: December 2007

Abstract
This paper presents the results of interwell tracer field work carried out in the McClesky sandstone in conjunction with a surfactant polymer flood pilot, a Dundee limestone pilot designated for an in-depth permeability modification treatment, and a Potter sand steam drive pilot. The objectives were to delineate fluid migration in the reservoirs and to compare tracer performance by co-injection. SCN was the best tracer in the sandstone with recoveries above 90%. In both the McCleskey and the Dundee, tritiated water recoveries were above 75%, with evidence of tritium – hydrogen exchange. Co57 and Co60 recoveries ranged from 35 to 55%. Tertiary butanol recoveries were near 75%, while about 50% of the injected isopropanol was recovered. The performance of ethanol, methanol and methyl ethyl ketone in the Dundee was similar to that of isopropanol. Residual oil saturations in the waterflood areas were measured using interwell tracers. The above alcohols and ionic salt tracers were used in the steam flood as vapor and water tracers, respectively. Strong signatures were observed for the alcohols, but the ionic tracer signatures were erratic.
Fitting Type Curves to Austin Chalk Wells
Authors: Poston S. W. , Chen H. Y. 
Published: December 2007

Abstract
A geological model of a typical Austin Chalk fracture system has been constructed. The geological model is composed of a major and at least one minor fracture system dividing the rock matrix into small sized blocks. Type curves representing the expected producing characteristics for a reservoir possessing at least two different permeability fracture systems and a matrix block system have been developed. These curves represent a combination of flow through a major fracture system with infinite conductivity, linear flow through a set of lesser, subsidiary micro-fractures, and flow from the matrix block system. The mathematical model replicating these expected conditions and providing the foundation for the type curves is discussed.
A field case study of an Austin Chalk lease shows the utility of the new, dual fracture-matrix concept to determine the variation of productive capacity and the degree of connectivity of offsetting wells. The six wells penetrating the 640 acre lease appear to have encountered four different producing systems.
Oilwell Coning Control Using Dual Completion With Tailpipe Water Sink
Authors: Wojtanowicz A. K. , Xu Hui , Bassiouni Z. 
Published: December 2007

Abstract
The paper describes the results of a simulation study of a novel method to control water coning in an oil producing well. This method uses a dual completion configuration: above and below OWC. In this configuration, the well section above OWC is completed in the oil zone and produces oil, while the well section completed below OWC in the water-saturated zone serves as a drain to control the rise of the water cone (tailpipe water sink).
The physical principle of coning control in this method results from the effect of the water sink upon flow potential between the sink and oil-production perforations. The effect depends upon the water sink flowrate, and it results in suppression of water coning.
The objective of this study was to investigate production performance of the well with and without the water sink tailpipe. At first, the water sink's position and flowrate were investigated as they affected the critical production rate of oil, i.e. maximum production rate without the water breakthrough. Next, a comparison was made between the amounts of water produced for greater than critical oil production rates in these two systems.
The comparison tests were designed as a series of simulated oil production cycles in a well/reservoir system of known geometry and reservoir properties. The coning behavior of the production system with the tailpipe water sink was mathematically modelled using the flow potential distribution generated by two constant-terminal-rate sinks located between the two linear boundaries and the constant-pressure outer radial boundary. This new model was verified by using the existing and simulated data of water coning in conventional wells and by setting the water sink flowrate at zero, with oil being the only produced fluid. Verification tests were used to select the type of oil reservoir with the thick oil zone and the small dip angle for further comparison studies.
In these studies, the amount of produced water with and without the tail water sink was calculated for production rates exceeding the water breakthrough levels in conventional wells. Field data was compared to the results obtained from the water sink model.
The study demonstrated the existence of an active mechanism to control water coning with the tailpipe water sink. The mechanism is particularly effective with low flowrate at the sink because it prevents the water cone from breaking through the oil zone into the producing perforations. Also evaluated were the configurations of the well/reservoir system for the tailpipe water sink process. This process yielded less produced water than the conventional method did at the same or higher oil rate.
Evaluation of Underbalanced Through-Tubing Perforating and Closed Chamber Test Interpretation Techniques
Authors: Manohar M. M. , Morris C. W. , Brunner S. R. , Hill D. D. 
Published: December 2007

Abstract
Underbalanced, through-tubing perforating operations represent a compromise between the pressure differential needed for effective perforation cleanup and the differential that causes sand production or tends to the the gun and cable. This paper explores the dynamic variables involved in through-tubing perforating and describes a new model developed to evaluate the underbalance perforating conditions and predict the effects on the wireline gun system. Using this model, formations can be aggressively perforated with the optimum safe underbalance pressure, and completion operations can also be combined with closed chamber test techniques to accurately evaluate the completion efficiency and initial reservoir parameters.
Utilizing new wireline technology to measure downhole pressure and temperature during perforating, operational data were obtained from numerous field tests to validate the dynamic model. The results indicate that the model reliably predicts the maximum underbalance to avoid sanding, the change in gas cushion pressure, the volume of reservoir fluid influx and the gun/cable movement Examples from Louisiana Gulf Coast wells are used to illustrate the application of the design model and the associated closed chamber test technique.
The transient pressure data from the closed chamber test are used to accurately evaluate reservoir parameters and completion efficiency. The data are analyzed by assuming the formation is subjected to an impulse rate created by briefly flowing the well. In addition, by measuring the surface and bottomhole pressure during the perforating operation, the approximate fillup rate can be determined as well as the cumulative volume of fluid entry. In the field examples presented, these data are utilized in other interpretation techniques, such as rate convolved pressure analysis, and the derived formation parameters are compared with conventional well test results.