Stanford University Department of Petroleum Engineering
Overview
Works:  137 works in 148 publications in 1 language and 296 library holdings 

Roles:  Researcher 
Publication Timeline
.
Most widely held works by
Stanford University
Laboratory measurement of sorption in porous media by
Stanford University(
Book
)
2 editions published between 1978 and 1991 in English and held by 1 WorldCat member library worldwide
In the past year a number of studies pertaining to geothermal well test analysis were conducted. In this paper a brief overview of progress on the following six subjects is presented: (1) earth tide effects on a closed reservoir, (2) transient pressure analysis of multilayered heterogeneous reservoirs, (3) interference testing with wellbore storage and skin at the producing well, (4) steam/water relative permeabilities, (5) transient rate and pressure buildup resulting from constant pressure production, and (6) transient pressure analysis of a parallelepiped reservoir
2 editions published between 1978 and 1991 in English and held by 1 WorldCat member library worldwide
In the past year a number of studies pertaining to geothermal well test analysis were conducted. In this paper a brief overview of progress on the following six subjects is presented: (1) earth tide effects on a closed reservoir, (2) transient pressure analysis of multilayered heterogeneous reservoirs, (3) interference testing with wellbore storage and skin at the producing well, (4) steam/water relative permeabilities, (5) transient rate and pressure buildup resulting from constant pressure production, and (6) transient pressure analysis of a parallelepiped reservoir
NEDO'S project on geothermal reservoir engineering  a reservoir engineering study of the Kirishima field, Japan(
)
2 editions published between 1976 and 1987 in English and held by 0 WorldCat member libraries worldwide
This study investigates pressure buildup behavior of wells with wellbore storage and skin in bounded circular reservoirs, when inner and outer boundary effects interact to fully or partially dominate the well pressure response. Using dimensionless pressure derivative as the dependent variable, we show that early time response is governed by C{sub D}e{sup 2S} and late time response by r{sub eD}²/C{sub D}. Equations are provided to estimate the limits of the intermediate time period, which corresponds to infinite acting radial flow and a semilog straight line on a pressuretime graph. We present a new buildup derivative type curve, incorporating inner boundary (earlytime) and outer boundary (latetime) effects. Applications of this type curve in buildup test design and interpretation are discussed. 2 figs., 8 refs
2 editions published between 1976 and 1987 in English and held by 0 WorldCat member libraries worldwide
This study investigates pressure buildup behavior of wells with wellbore storage and skin in bounded circular reservoirs, when inner and outer boundary effects interact to fully or partially dominate the well pressure response. Using dimensionless pressure derivative as the dependent variable, we show that early time response is governed by C{sub D}e{sup 2S} and late time response by r{sub eD}²/C{sub D}. Equations are provided to estimate the limits of the intermediate time period, which corresponds to infinite acting radial flow and a semilog straight line on a pressuretime graph. We present a new buildup derivative type curve, incorporating inner boundary (earlytime) and outer boundary (latetime) effects. Applications of this type curve in buildup test design and interpretation are discussed. 2 figs., 8 refs
Productivity and injectivity of horizontal wells. Annual report, March 10, 1993March 9, 1994(
)
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
In this report, the investigators review a range of reservoir scenarios in which horizontal wells can be advantageous and discuss some of the modeling problems associated with calculating well connection factors, productivity indices, coning behavior and well twophase pressure drops. We show illustrative coning calculations and the implications of the well model on distribution of postbreakthrough gas saturations. Such calculations then open up the possibility of determining optimal recompletion strategies and/or additional hydraulic fracturing
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
In this report, the investigators review a range of reservoir scenarios in which horizontal wells can be advantageous and discuss some of the modeling problems associated with calculating well connection factors, productivity indices, coning behavior and well twophase pressure drops. We show illustrative coning calculations and the implications of the well model on distribution of postbreakthrough gas saturations. Such calculations then open up the possibility of determining optimal recompletion strategies and/or additional hydraulic fracturing
Productivity and injectivity of horizontal wells. Quarterly report, January 1, 1996  March 31, 1996(
)
1 edition published in 1996 in English and held by 0 WorldCat member libraries worldwide
A reservoir simulator solves the flow equations numerically on grids defining a reservoir region. However, when a well is located in a gridblock, the block pressure is not equal to the well pressure. In order to join the well to the grid blocks in which the well is located, it is usual to use a single phase model to obtain the appropriate Well Index. The Well Index is based on the concept of an effective well radius at which the pressure of the block applies. This approach requires the flow in the area around the well to be radial. Peaceman has proposed more general expressions for the effective radius, but all based on 2D flow. As reservoirs are generally thin, a horizontal well cannot be far from the top or bottom boundary. In the case of multilateral wells, the situation is even worse, since the flow is perturbed not only by the boundaries but also by the other wells. Moreover, horizontal wells can be efficient in low permeability reservoirs, where the steadystate (or pseudosteadystate) regime does not establish rapidly. This means that a single constant value for the well index cannot be used for all times. The objective of this study is then to evaluate well indices for different configurations of horizontal wells. The well index will be computed for a homogeneous anisotropic singlephase flow and will then be reintroduced in the simulator for the full threephase study. The well index relates the pressure in the block to the pressure in the well for a given flow rate. If these two pressures are known, the well index can be deduced easily. The block pressure can be evaluated by a simulator. The well pressure for a threedimensional singlephase flow is not known analytically in general, but can be computed by the semianalytical method described briefly below
1 edition published in 1996 in English and held by 0 WorldCat member libraries worldwide
A reservoir simulator solves the flow equations numerically on grids defining a reservoir region. However, when a well is located in a gridblock, the block pressure is not equal to the well pressure. In order to join the well to the grid blocks in which the well is located, it is usual to use a single phase model to obtain the appropriate Well Index. The Well Index is based on the concept of an effective well radius at which the pressure of the block applies. This approach requires the flow in the area around the well to be radial. Peaceman has proposed more general expressions for the effective radius, but all based on 2D flow. As reservoirs are generally thin, a horizontal well cannot be far from the top or bottom boundary. In the case of multilateral wells, the situation is even worse, since the flow is perturbed not only by the boundaries but also by the other wells. Moreover, horizontal wells can be efficient in low permeability reservoirs, where the steadystate (or pseudosteadystate) regime does not establish rapidly. This means that a single constant value for the well index cannot be used for all times. The objective of this study is then to evaluate well indices for different configurations of horizontal wells. The well index will be computed for a homogeneous anisotropic singlephase flow and will then be reintroduced in the simulator for the full threephase study. The well index relates the pressure in the block to the pressure in the well for a given flow rate. If these two pressures are known, the well index can be deduced easily. The block pressure can be evaluated by a simulator. The well pressure for a threedimensional singlephase flow is not known analytically in general, but can be computed by the semianalytical method described briefly below
Productivity and injectivity of horizontal wells. Quarterly report, April 1, 1994June 30, 1994(
)
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
In the fifth quarter of this project, progress was made concerning four of the stated objectives of the project. First, extensive sensitivity studies, based on reservoir simulation, have been performed on a field example to assess the effects of wellbore friction, inflow, skin, length, and diameter of the well, etc. on the productivity of a horizontal well. Secondly, the authors have launched a new phase of the project on developing models for scaleup and coarse grid pseudo functions for horizontal wells in heterogeneous reservoirs. The available methods have been applied to an example problem and their performance and limitations have been analyzed. Thirdly, the authors are in the process of developing a new analytical solution for the coning and cresting critical rates for horizontal wells. Finally, experimental data bases will be used to test the authors' newly developed general mechanistic model for twophase flow
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
In the fifth quarter of this project, progress was made concerning four of the stated objectives of the project. First, extensive sensitivity studies, based on reservoir simulation, have been performed on a field example to assess the effects of wellbore friction, inflow, skin, length, and diameter of the well, etc. on the productivity of a horizontal well. Secondly, the authors have launched a new phase of the project on developing models for scaleup and coarse grid pseudo functions for horizontal wells in heterogeneous reservoirs. The available methods have been applied to an example problem and their performance and limitations have been analyzed. Thirdly, the authors are in the process of developing a new analytical solution for the coning and cresting critical rates for horizontal wells. Finally, experimental data bases will be used to test the authors' newly developed general mechanistic model for twophase flow
Scaleup of miscible flood processes(
)
2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide
Results of a wideranging investigation of the scaling of the physical mechanisms of miscible floods are reported. Advanced techniques for analysis of crude oils are considered in Chapter 2. Application of supercritical fluid chromatography is demonstrated for characterization of crude oils for equationofstate calculations of phase equilibrium. Results of measurements of crude oil and phase compositions by gas chromatography and mass spectrometry are also reported. The theory of development of miscibility is considered in detail in Chapter 3. The theory is extended to four components, and sample solutions for a variety of gas injection systems are presented. The analytical theory shows that miscibility can develop even though standard tieline extension criteria developed for ternary systems are not satisfied. In addition, the theory includes the first analytical solutions for condensing/vaporizing gas drives. In Chapter 4, methods for simulation of viscous fingering are considered. The scaling of the growth of transition zones in linear viscous fingering is considered. In addition, extension of the models developed previously to three dimensions is described, as is the inclusion of effects of equilibrium phase behavior. In Chapter 5, the combined effects of capillary and gravitydriven crossflow are considered. The experimental results presented show that very high recovery can be achieved by gravity segregation when interfacial tensions are moderately low. We argue that such crossflow mechanisms are important in multicontact miscible floods in heterogeneous reservoirs. In addition, results of flow visualization experiments are presented that illustrate the interplay of crossflow driven by gravity with that driven by viscous forces
2 editions published in 1992 in English and held by 0 WorldCat member libraries worldwide
Results of a wideranging investigation of the scaling of the physical mechanisms of miscible floods are reported. Advanced techniques for analysis of crude oils are considered in Chapter 2. Application of supercritical fluid chromatography is demonstrated for characterization of crude oils for equationofstate calculations of phase equilibrium. Results of measurements of crude oil and phase compositions by gas chromatography and mass spectrometry are also reported. The theory of development of miscibility is considered in detail in Chapter 3. The theory is extended to four components, and sample solutions for a variety of gas injection systems are presented. The analytical theory shows that miscibility can develop even though standard tieline extension criteria developed for ternary systems are not satisfied. In addition, the theory includes the first analytical solutions for condensing/vaporizing gas drives. In Chapter 4, methods for simulation of viscous fingering are considered. The scaling of the growth of transition zones in linear viscous fingering is considered. In addition, extension of the models developed previously to three dimensions is described, as is the inclusion of effects of equilibrium phase behavior. In Chapter 5, the combined effects of capillary and gravitydriven crossflow are considered. The experimental results presented show that very high recovery can be achieved by gravity segregation when interfacial tensions are moderately low. We argue that such crossflow mechanisms are important in multicontact miscible floods in heterogeneous reservoirs. In addition, results of flow visualization experiments are presented that illustrate the interplay of crossflow driven by gravity with that driven by viscous forces
Productivity and injectivity of horizontal wells. Annual report for the period, March 10, 1994March 9, 1995 by F. J Fayers(
)
1 edition published in 1995 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 1995 in English and held by 0 WorldCat member libraries worldwide
Gaseous species in fluid inclusions : a tracer of fluids and indicator of fluid processes(
)
1 edition published in 1976 in English and held by 0 WorldCat member libraries worldwide
Most of the theoretical study on heat and mass transfer in geothermal reservoirs has been based on numerical method. Recently at the 1975 NSF Workshop on Geothermal Reservoir Engineering, Cheng presented a number of analytical solutions based on boundary layer approximations which are valid for porous media at high Rayleigh numbers. according to various estimates the Rayleigh number for the Wairakei geothermal field in New Zealand is in the range of 10005000, which is typical for a viable geothermal field consisting of a highly permeable formation and a heat source at sufficiently high temperature. The basic assumption of boundary layer theory is that heat convective heat transfer takes place in a thin porous layer adjacent to heated or cooled surfaces. Indeed, numerical solutions suggest that temperature and velocity boundary layers do exist in porous media at high Rayleigh numbers. It is worth mentioning that the large velocity gradient existing near the heated or cooled surfaces is not due to viscosity but is induced by the buoyancy effects. The present paper is a summary of the work that we have done on the analytical solutions of heat and mass transfer in a porous medium based on the boundary layer approximations since the 1975 Workshop. As in the classical convective heat transfer theory, boundary layer approximations in porous layer flows can result in analytical solutions. Mathematically, the approximations are the firstorder terms of an asymptotic expansion which is valid for high Rayleigh numbers. Comparison with experimental data and numerical solutions show that the approximations are also accurate at moderate values of Rayleigh numbers. For problems with low Rayleigh numbers where boundary layer is thick, higherorder approximations must be used. 9 refs., 5 figs
1 edition published in 1976 in English and held by 0 WorldCat member libraries worldwide
Most of the theoretical study on heat and mass transfer in geothermal reservoirs has been based on numerical method. Recently at the 1975 NSF Workshop on Geothermal Reservoir Engineering, Cheng presented a number of analytical solutions based on boundary layer approximations which are valid for porous media at high Rayleigh numbers. according to various estimates the Rayleigh number for the Wairakei geothermal field in New Zealand is in the range of 10005000, which is typical for a viable geothermal field consisting of a highly permeable formation and a heat source at sufficiently high temperature. The basic assumption of boundary layer theory is that heat convective heat transfer takes place in a thin porous layer adjacent to heated or cooled surfaces. Indeed, numerical solutions suggest that temperature and velocity boundary layers do exist in porous media at high Rayleigh numbers. It is worth mentioning that the large velocity gradient existing near the heated or cooled surfaces is not due to viscosity but is induced by the buoyancy effects. The present paper is a summary of the work that we have done on the analytical solutions of heat and mass transfer in a porous medium based on the boundary layer approximations since the 1975 Workshop. As in the classical convective heat transfer theory, boundary layer approximations in porous layer flows can result in analytical solutions. Mathematically, the approximations are the firstorder terms of an asymptotic expansion which is valid for high Rayleigh numbers. Comparison with experimental data and numerical solutions show that the approximations are also accurate at moderate values of Rayleigh numbers. For problems with low Rayleigh numbers where boundary layer is thick, higherorder approximations must be used. 9 refs., 5 figs
Productivity and injectivity of horizontal wells. Quarterly report, July 1September 30, 1996(
)
1 edition published in 1996 in English and held by 0 WorldCat member libraries worldwide
This quarterly report reports on the efforts on Task 2, effects of reservoir heterogeneities on performance prediction of horizontal wells. Performance prediction of horizontal and nonconventional wells based on both analytical and numerical tools rarely match actual performance. Even a history matched case with sufficient production data fails to give reliable predictions for long times. In this study the authors explore reasons for the inability of predictive tools to make accurate predictions. They consider a case where a vertical well has been drilled and cored. Then, they generate twenty consistent geostatistical descriptions of permeability and porosity that are all constrained to hard data obtained from the vertical well. Simulations with these realizations show large differences in production rate, WOR and GOR predictions as a result of variations in reservoir properties. It is also shown that the effect of well index (WI) on simulation results is large. Furthermore, for the example considered, analytical models for critical rate and productivity calculations were found to have limited practical use
1 edition published in 1996 in English and held by 0 WorldCat member libraries worldwide
This quarterly report reports on the efforts on Task 2, effects of reservoir heterogeneities on performance prediction of horizontal wells. Performance prediction of horizontal and nonconventional wells based on both analytical and numerical tools rarely match actual performance. Even a history matched case with sufficient production data fails to give reliable predictions for long times. In this study the authors explore reasons for the inability of predictive tools to make accurate predictions. They consider a case where a vertical well has been drilled and cored. Then, they generate twenty consistent geostatistical descriptions of permeability and porosity that are all constrained to hard data obtained from the vertical well. Simulations with these realizations show large differences in production rate, WOR and GOR predictions as a result of variations in reservoir properties. It is also shown that the effect of well index (WI) on simulation results is large. Furthermore, for the example considered, analytical models for critical rate and productivity calculations were found to have limited practical use
Scaleup of miscible flood processes for heterogeneous reservoirs. Quarterly report, January 1March 31,1995(
)
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
The current project is a systematic research effort aimed at quantifying relationships between process mechanisms that can lead to improved recovery from gas injection processes performed in heterogeneous Class 1 and Class 2 reservoirs. It will provide a rational basis for the design of displacement processes that take advantage of crossfiow due to capillary, gravity and viscous forces to offset partially the adverse effects of heterogeneity. In effect, the high permeability zones are used to deliver fluid by crossflow to zones that would otherwise be flooded only very slowly. Thus, the research effort is divided into five areas: development of miscibility in multicomponent systems; design estimates for nearly miscible displacements; design of miscible floods for fractured reservoirs; compositional flow visualization experiments and simulation of nearmiscible flow in heterogeneous systems. The status of the research effort in each area is reviewed briefly. In addition, results from porelevel modelling of threephase flow in porous media are presented
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
The current project is a systematic research effort aimed at quantifying relationships between process mechanisms that can lead to improved recovery from gas injection processes performed in heterogeneous Class 1 and Class 2 reservoirs. It will provide a rational basis for the design of displacement processes that take advantage of crossfiow due to capillary, gravity and viscous forces to offset partially the adverse effects of heterogeneity. In effect, the high permeability zones are used to deliver fluid by crossflow to zones that would otherwise be flooded only very slowly. Thus, the research effort is divided into five areas: development of miscibility in multicomponent systems; design estimates for nearly miscible displacements; design of miscible floods for fractured reservoirs; compositional flow visualization experiments and simulation of nearmiscible flow in heterogeneous systems. The status of the research effort in each area is reviewed briefly. In addition, results from porelevel modelling of threephase flow in porous media are presented
Productivity and injectivity of horizontal wells. Annual report, March 10, 1996March 9, 1997(
)
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
Progress is reported on the following tasks: advanced modeling of horizontal wells; heterogeneous effects of reservoirs; development of improved methods for calculating multiphase pressure drops within the wellbore; pseudofunctions; development of multiwell models;testing of HW models with field examples; enhanced oil recovery applications; and application studies and their optimization
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
Progress is reported on the following tasks: advanced modeling of horizontal wells; heterogeneous effects of reservoirs; development of improved methods for calculating multiphase pressure drops within the wellbore; pseudofunctions; development of multiwell models;testing of HW models with field examples; enhanced oil recovery applications; and application studies and their optimization
Productivity and injectivity of horizontal wells. [Quarterly report], March 10, 1993June 30, 1993(
)
1 edition published in 1993 in English and held by 0 WorldCat member libraries worldwide
This project has been set up for the purpose of developing advanced performance prediction methods for horizontal wells (HWs) in heterogeneous reservoirs. The stimulus for this project arises from the fact that HWs are now being drilled in large numbers (e.g., over 900 HWs in 1992) and their benefits have provided the one example of an advanced oil recovery technique which is proving to be a general economic attraction. While the drilling techniques and completion practice have made great advances in the last 5 years, the position on reservoir engineering attributes and optimization of reservoir performance lags behind the other technical areas. This project has eight major objectives, of which in year one the following three tasks are involved: modeling horizontal wells; reservoir characterization; and experimental planning and interpretation. Technical progress of these tasks are presented
1 edition published in 1993 in English and held by 0 WorldCat member libraries worldwide
This project has been set up for the purpose of developing advanced performance prediction methods for horizontal wells (HWs) in heterogeneous reservoirs. The stimulus for this project arises from the fact that HWs are now being drilled in large numbers (e.g., over 900 HWs in 1992) and their benefits have provided the one example of an advanced oil recovery technique which is proving to be a general economic attraction. While the drilling techniques and completion practice have made great advances in the last 5 years, the position on reservoir engineering attributes and optimization of reservoir performance lags behind the other technical areas. This project has eight major objectives, of which in year one the following three tasks are involved: modeling horizontal wells; reservoir characterization; and experimental planning and interpretation. Technical progress of these tasks are presented
Doublets and other allied well patterns(
)
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
Whenever a liquid is injected into an infinite reservoir containing liquid with the same flow properties, the equations of flow are well known. The pressures in such a system vary over time and distance (radius) in ways that depend on the formation and liquid flow properties. Such equations are well knownthey form the basis for the voluminous welltesting literature in petroleum engineering and ground water hydrology. Suppose there are two wellsone an injector and one a producerwith identical rates. The behavior of this system can be calculated using superposition; which merely means that the results can be added independently of each other. When this is done, the remarkable result is that after a period of time there is a region that approaches steady state flow. Thereafter, the pressures and flow velocities in this region stay constant. The size of this region increases with time. This ''steady state'' characteristic can be used to solve a number of interesting and useful problems, both in heat transfer and in fluid flow. The heat transfer problems can be addressed because the equations are identical in form. A number of such problems are solved herein for doublet systems. In addition, concepts are presented to help solve other cases that flow logically from the problems solved herein. It is not necessary that only two wells be involved. It turns out that any time the total injection and production are equal, the system approaches steady state. This idea is also addressed in these notes. A number of useful multiwell cases are addressed to present the flavor of such solutions
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
Whenever a liquid is injected into an infinite reservoir containing liquid with the same flow properties, the equations of flow are well known. The pressures in such a system vary over time and distance (radius) in ways that depend on the formation and liquid flow properties. Such equations are well knownthey form the basis for the voluminous welltesting literature in petroleum engineering and ground water hydrology. Suppose there are two wellsone an injector and one a producerwith identical rates. The behavior of this system can be calculated using superposition; which merely means that the results can be added independently of each other. When this is done, the remarkable result is that after a period of time there is a region that approaches steady state flow. Thereafter, the pressures and flow velocities in this region stay constant. The size of this region increases with time. This ''steady state'' characteristic can be used to solve a number of interesting and useful problems, both in heat transfer and in fluid flow. The heat transfer problems can be addressed because the equations are identical in form. A number of such problems are solved herein for doublet systems. In addition, concepts are presented to help solve other cases that flow logically from the problems solved herein. It is not necessary that only two wells be involved. It turns out that any time the total injection and production are equal, the system approaches steady state. This idea is also addressed in these notes. A number of useful multiwell cases are addressed to present the flavor of such solutions
Productivity and Injectivity of Hoeizontal Wells(
)
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
A number of activities have been carried out in the last three months. A list outlining these efforts is presented below. The Ph. D. Dissertation on developing correlations for breakthrough time and post breakthrough behavior of horizontal wells was successfully defended in March. A paper on this work will be presented in the Fifth SPE Latin American and Caribbean Conference to be held in Rio de Janeiro, Brazil in September. Multilateral wells offer higher productivity than single horizontal wells. However, the increase in their productivity depends on the length and form of the laterals. We have initiated a simulation study to investigate the productivity of multilateral wells in terms of their arrangement and positioning. The experimental work on using horizontal wells as injectors and producers in a gas injection gravity drainage process is progressing. Experimental setup is near completion and trial runs will follow next. Work on generalized gridding methods continued by considering streamline grids. In this approach, gridblock boundaries are aligned along streamlines to better rep resent flow paths governed by heterogeneities. The correct well index for a typical partially penetrating horizontal well could be very different from the classical well index and can be calculated in a semi analytical fashion in which the well pressure is obtained analytically and the well block pressure is computed numerically. In the so called explicit well modeling approach, the need to calculate any well index is eliminated by fine gridding the well. We have studied this second approach and have shown that it can lead to incorrect results. The last activity listed above is the subject of this quarterly report
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
A number of activities have been carried out in the last three months. A list outlining these efforts is presented below. The Ph. D. Dissertation on developing correlations for breakthrough time and post breakthrough behavior of horizontal wells was successfully defended in March. A paper on this work will be presented in the Fifth SPE Latin American and Caribbean Conference to be held in Rio de Janeiro, Brazil in September. Multilateral wells offer higher productivity than single horizontal wells. However, the increase in their productivity depends on the length and form of the laterals. We have initiated a simulation study to investigate the productivity of multilateral wells in terms of their arrangement and positioning. The experimental work on using horizontal wells as injectors and producers in a gas injection gravity drainage process is progressing. Experimental setup is near completion and trial runs will follow next. Work on generalized gridding methods continued by considering streamline grids. In this approach, gridblock boundaries are aligned along streamlines to better rep resent flow paths governed by heterogeneities. The correct well index for a typical partially penetrating horizontal well could be very different from the classical well index and can be calculated in a semi analytical fashion in which the well pressure is obtained analytically and the well block pressure is computed numerically. In the so called explicit well modeling approach, the need to calculate any well index is eliminated by fine gridding the well. We have studied this second approach and have shown that it can lead to incorrect results. The last activity listed above is the subject of this quarterly report
Scaleup of miscible flood processes for heterogeneous reservoirs. Quarterly report, April 1, 1994June 30, 1994(
)
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
The current project is a systematic research effort to quantify relationships between process mechanisms that can lead to improved recovery from gas injection processes performed in heterogeneous Class 1 and Class 2 reservoirs. It will provide a rational basis for the design of displacement processes that take advantage of crossflow due to capillary, gravity and viscous forces to offset partially the adverse effects of heterogeneity. In effect, the high permeability zones are used to deliver fluid by crossflow to zones that would otherwise be flooded only very slowly. Thus, the research effort is divided into five areas: (a) Development of miscibility in multicomponent systems, (b) Design estimates for nearly miscible displacements, (c) Design of miscible floods for fractured reservoirs (d), Compositional flow visualization experiments, and (e) Simulation of nearmiscible flow in heterogeneous systems. The status of the research effort in each area is reviewed briefly in the following section
1 edition published in 1994 in English and held by 0 WorldCat member libraries worldwide
The current project is a systematic research effort to quantify relationships between process mechanisms that can lead to improved recovery from gas injection processes performed in heterogeneous Class 1 and Class 2 reservoirs. It will provide a rational basis for the design of displacement processes that take advantage of crossflow due to capillary, gravity and viscous forces to offset partially the adverse effects of heterogeneity. In effect, the high permeability zones are used to deliver fluid by crossflow to zones that would otherwise be flooded only very slowly. Thus, the research effort is divided into five areas: (a) Development of miscibility in multicomponent systems, (b) Design estimates for nearly miscible displacements, (c) Design of miscible floods for fractured reservoirs (d), Compositional flow visualization experiments, and (e) Simulation of nearmiscible flow in heterogeneous systems. The status of the research effort in each area is reviewed briefly in the following section
Scaleup of miscible flood processes. [Quarterly report], January 1April 31, 1992(
)
1 edition published in 1992 in English and held by 0 WorldCat member libraries worldwide
Efficient application of miscible floods to heterogeneous reservoirs requires the designer to take advantage of more than one of the physical mechanisms that act and interact to determine displacement performance. In this report, the investigators summarize the interactions of phase behavior, nonuniform flow, and crossflow and based on novel results obtained during the course of their experimental efforts. They suggest design opportunities for application of gas injection to nearmiscible recovery processes, to enhanced gravity drainage, and even to fractured reservoirs. To design such processes intelligently, the quantitative scaling of the interplay of phase equilibria, reservoir heterogeneity, viscous fingering and particularly crossflow must be understood. In essence, they propose to make use of crossflow, i.e. transport in the direction transverse to the basic flow direction, to sweep portions of reservoirs that can be reached only very slowly by direct displacement. In this report, the core displacement and flow visualization experiments described suggest that the effects of low interfacial tensions (IFT's) and gravity can be used to advantage in the design of multicontact miscible displacements for heterogeneous reservoirs, including fractured reservoirs
1 edition published in 1992 in English and held by 0 WorldCat member libraries worldwide
Efficient application of miscible floods to heterogeneous reservoirs requires the designer to take advantage of more than one of the physical mechanisms that act and interact to determine displacement performance. In this report, the investigators summarize the interactions of phase behavior, nonuniform flow, and crossflow and based on novel results obtained during the course of their experimental efforts. They suggest design opportunities for application of gas injection to nearmiscible recovery processes, to enhanced gravity drainage, and even to fractured reservoirs. To design such processes intelligently, the quantitative scaling of the interplay of phase equilibria, reservoir heterogeneity, viscous fingering and particularly crossflow must be understood. In essence, they propose to make use of crossflow, i.e. transport in the direction transverse to the basic flow direction, to sweep portions of reservoirs that can be reached only very slowly by direct displacement. In this report, the core displacement and flow visualization experiments described suggest that the effects of low interfacial tensions (IFT's) and gravity can be used to advantage in the design of multicontact miscible displacements for heterogeneous reservoirs, including fractured reservoirs
Pressure drawdown analysis for the Travale 22 well(
)
1 edition published in 1978 in English and held by 0 WorldCat member libraries worldwide
This work presents preliminary results on the analysis of drawdown data for Travale 22. Both wellhead pressure and flow rate data were recorded in this well for over a period of almost two years. In the past, Barelli et al. (1975) and Atkinson et al. (1977) presented the analysis of five pressure buildup tests. Figure 1 shows the Horner plot for these cases. They found that to have a good match in all cases, it was necessary to assume that the Travale 22 well is intersected by a partially penetrating vertical fracture in a parallelpiped whose bottom side is maintained at constant pressure (boiling front), as shown in Fig. 2. Atkinson et al. also presented an analysis for a pressure interface test run in the TravaleRadicondoli area. In this case, the Travale 22 well was flowing and the pressure recorded at wells R1, R3, R5, R6, R9, and Chl (see Fig. 3) . Analysis of these data showed that pressure interference in this reservoir can be matched by considering pure linear flow (Figs. 4 and 5) . This indicated the possible presence of a vertical fracture intersecting the Travale 22 well. It was determined that fracture is oriented along the N73{sup o}W direction. In addition, the pressure interference data showed that no boundary exists within 2 kilometers from the fracture plane. It was mentioned that linear flow should take place in both horizontal and vertical directions
1 edition published in 1978 in English and held by 0 WorldCat member libraries worldwide
This work presents preliminary results on the analysis of drawdown data for Travale 22. Both wellhead pressure and flow rate data were recorded in this well for over a period of almost two years. In the past, Barelli et al. (1975) and Atkinson et al. (1977) presented the analysis of five pressure buildup tests. Figure 1 shows the Horner plot for these cases. They found that to have a good match in all cases, it was necessary to assume that the Travale 22 well is intersected by a partially penetrating vertical fracture in a parallelpiped whose bottom side is maintained at constant pressure (boiling front), as shown in Fig. 2. Atkinson et al. also presented an analysis for a pressure interface test run in the TravaleRadicondoli area. In this case, the Travale 22 well was flowing and the pressure recorded at wells R1, R3, R5, R6, R9, and Chl (see Fig. 3) . Analysis of these data showed that pressure interference in this reservoir can be matched by considering pure linear flow (Figs. 4 and 5) . This indicated the possible presence of a vertical fracture intersecting the Travale 22 well. It was determined that fracture is oriented along the N73{sup o}W direction. In addition, the pressure interference data showed that no boundary exists within 2 kilometers from the fracture plane. It was mentioned that linear flow should take place in both horizontal and vertical directions
Productivity and injectivity of horizontal wells: quarterly report, July 1, 1993  September 30, 1993(
)
1 edition published in 1993 in English and held by 0 WorldCat member libraries worldwide
A number of research activities have been carried out in the last three months. A list outlining these efforts is presented below followed by brief description of each activity in the subsequent sections of this report: (1) The available analytical solutions in the literature for steady state critical rates of horizontal wells are examined. Application of these methods to a cresting example show significant uncertainties in prediction of critical rates. (2) Sensitivity computations have been run for evaluating the effects of shale distribution on the performance of horizontal wells in heterogeneous reservoirs. (3) A number of single phase (water and oil) and twophase (water and air) experiments have been completed in the Marathon Wellbore Model and the collected data are being analyzed. (4) A presentation of our project was given in the International Technology Forum DEA44/67 on Horizontal, Slimhole, and Coiled Tubing, held by Maurer. (5) Our draft review report entitled ''Opportunities for Horizontal Wells and Problems in Predicting Their Performance'' has been completed
1 edition published in 1993 in English and held by 0 WorldCat member libraries worldwide
A number of research activities have been carried out in the last three months. A list outlining these efforts is presented below followed by brief description of each activity in the subsequent sections of this report: (1) The available analytical solutions in the literature for steady state critical rates of horizontal wells are examined. Application of these methods to a cresting example show significant uncertainties in prediction of critical rates. (2) Sensitivity computations have been run for evaluating the effects of shale distribution on the performance of horizontal wells in heterogeneous reservoirs. (3) A number of single phase (water and oil) and twophase (water and air) experiments have been completed in the Marathon Wellbore Model and the collected data are being analyzed. (4) A presentation of our project was given in the International Technology Forum DEA44/67 on Horizontal, Slimhole, and Coiled Tubing, held by Maurer. (5) Our draft review report entitled ''Opportunities for Horizontal Wells and Problems in Predicting Their Performance'' has been completed
Productivity and injectivity of horizontal wells. Quarterly report, January 1, 1995March 31, 1995(
)
1 edition published in 1995 in English and held by 0 WorldCat member libraries worldwide
This report presents skin factor calculations for vertical, horizontal, and deviated wells. Calculations for perforation, damage zone, crushed zone, nondarcy flow, and pressure drop due to the gravel packs are included
1 edition published in 1995 in English and held by 0 WorldCat member libraries worldwide
This report presents skin factor calculations for vertical, horizontal, and deviated wells. Calculations for perforation, damage zone, crushed zone, nondarcy flow, and pressure drop due to the gravel packs are included
Productivity and injectivity of horizontal wells. Quarterly report, October 1December 31, 1996(
)
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
This report describes progress on Tasks 1 and 4, Correlations for cresting behavior in horizontal wells. Research work on developing coarse grid methods to study cresting in horizontal wells was continued. The previous correlations for optimum grid size, breakthrough time, and post breakthrough behavior (i.e., wateroil ratio) were further tested and optimized. Procedures to derive pseudofunctions either using numerical correlations or coarse grid simulations have been proposed and successfully tested. The results reported here and other calculations show that the correlations developed in this work can be applied to a wide range of conditions for predicting the water breakthrough time (BT) and the wateroilratio (PBB) for horizontal wells. All of the correlations are based on the assumption of twophase, twodimensional flow in homogeneous reservoirs
1 edition published in 1997 in English and held by 0 WorldCat member libraries worldwide
This report describes progress on Tasks 1 and 4, Correlations for cresting behavior in horizontal wells. Research work on developing coarse grid methods to study cresting in horizontal wells was continued. The previous correlations for optimum grid size, breakthrough time, and post breakthrough behavior (i.e., wateroil ratio) were further tested and optimized. Procedures to derive pseudofunctions either using numerical correlations or coarse grid simulations have been proposed and successfully tested. The results reported here and other calculations show that the correlations developed in this work can be applied to a wide range of conditions for predicting the water breakthrough time (BT) and the wateroilratio (PBB) for horizontal wells. All of the correlations are based on the assumption of twophase, twodimensional flow in homogeneous reservoirs
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 United States Department of Energy Office of Scientific and Technical Information Distributor
 United States Department of Energy Sponsor
 National Energy Technology Laboratory (U.S.) Researcher
 United States Office of the Assistant Secretary for Fossil Energy Sponsor
 United States Department of Energy Geothermal Division Researcher
 Stanford University Petroleum Research Institute
 Stanford University School of Earth Sciences
 Kovscek, Anthony R. Author
 Stanford Geothermal Program (U.S.)
 United States National Petroleum Technology Office
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Stanford University. Department of Energy Resources Engineering
Stanford University. School of Earth Sciences
Stanford University. Dept. of Petroleum Engineering
Stanford University. Petroleum Engineering Department
Stanford University. School of Earth Sciences. Department of Petroleum Engineering
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