The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform
Shahab Gerami - One of the best experts on this subject based on the ideXlab platform.
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A new approach for analysis of production data from constant production rate wells in gas condensate reservoirs
Journal of Natural Gas Science and Engineering, 2014Co-Authors: Milad Arabloo, Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Abstract Production data analysis provides key parameters to a series of reservoir engineering calculations such as reserve estimation, inflow performance calculations, and well production forecast. Although techniques of production data analysis for oil and dry gas reservoirs have advanced significantly over the past few decades, application of these techniques for analyzing production data of gas condensate reservoirs has not been fully studied despite its great practical importance. In this work, a simple yet accurate methodology is presented for reliable estimation of initial gas in place and average reservoir pressure in gas condensate reservoirs. We define new pseudopressure and Material Balance Time functions suitable for gas condensate systems. According to our observations, a Cartesian plot of modified normalized pseudopressure versus modified Material Balance pseudoTime of gas condensate production data yields three distinct regions. In this study we will show that the middle region is unusable and should be distinguished and removed from the analysis. The required input data are bottom hole flowing pressures, gas and condensate production rates, and constant volume depletion (CVD) test data. This study provides example analyses and establishes guidelines for the analysis and interpretation of long term production data in gas condensate reservoirs using developed Cartesian plot.
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New Modification on Production Data of Gas Condensate Reservoirs for Rate Transient Analysis
Petroleum Science and Technology, 2014Co-Authors: A. Sadeghi Boogar, Shahab Gerami, Mohsen MasihiAbstract:Techniques of production data analysis for single-phase oil and gas reservoirs have advanced significantly over the past few years. These techniques range from traditional (i.e., Arps, 1945; Fetkovich, 1980) to modern methods that account for the variation of operating conditions at the wellbore. However, the application of these later methods to gas condensate reservoirs is a challenge. The authors aimed to extend the applicability of modern production data analysis (single-phase flow) to analyze the production data of a gas condensate reservoir (two-phase flow). A single-phase production model consists of (a) a Material Balance equation, (b) the solution of diffusivity equation for gas flow subjected to constant rate and constant pressure boundary conditions, and (c) the presentation of a Material-Balance-Time function. Using a compositional reservoir simulator, long-term production data have been generated over a wide range of the gas condensate reservoir parameters. The simulation result is compared w...
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A New Model for Modern Production-Decline Analysis of Gas/Condensate Reservoirs
Journal of Canadian Petroleum Technology, 2011Co-Authors: Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Modern production-decline analysis is a robust technique for analysis of production data from a well under variable operating conditions. It uses production rates and flowing pressures to provide reliable estimates of recoverable reserves and fluid in place. The mathematics behind this technique is similar to that of pressure-transient theory; however, the focus is different. It deals with long-term variable production data instead of short-term constant-rate transient data. Using modern decline analysis for two-phase-flow conditions (e.g., gas/condensate reservoirs) is under question because of the single-phase-flow assumption in the development of the "Material-Balance Time" function. This is a Time function that converts any decline (e.g., exponential decline) to harmonic decline to account for variable operating conditions. The purpose of this work is to develop a model to use the concepts of modern techniques for analyzing production data of single-porosity gas/condensate reservoirs. For this purpose, the governing flow equation is linearized, using appropriately defined pseudopressure and pseudoTime functions. Then, the solution is obtained for constant-well-rate condition. This is followed by employing the superposition theorem to account for variable well pressure/rate conditions, resulting in definition of two-phase Material-Balance pseudoTime. The solution developed here is coupled with an appropriate Material-Balance equation and used to estimate the average reservoir pressure and original gas in place from analyzing production data. The dependency of relative permeability on capillary number and non-Darcy flow is included in the formulation. Verification of the proposed method is obtained with the analysis of synthetic production data using a series of fine-grid compositional numerical simulations over a typical range of gas/ condensate-reservoir parameters.
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A New Model for Modern Production-Decline Analysis of Gas/Condensate Reservoirs
Journal of Canadian Petroleum Technology, 2011Co-Authors: Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Summary Modern production-decline analysis is a robust technique for analysis of production data from a well under variable operating conditions. It uses production rates and flowing pressures to provide reliable estimates of recoverable reserves and fluid in place. The mathematics behind this technique is similar to that of pressure-transient theory; however, the focus is different. It deals with long-term variable production data instead of short-term constant-rate transient data. Using modern decline analysis for two-phase-flow conditions (e.g., gas/condensate reservoirs) is under question because of the single-phase-flow assumption in the development of a "Material-Balance Time" function. This is a Time function that converts any decline (e.g., exponential decline) to harmonic decline to account for variable operating conditions. The purpose of this work is to develop a model to use the concepts of modern techniques for analyzing production data of single-porosity gas/condensate reservoirs. For this purpose, the governing flow equation is linearized, using appropriately defined pseudopressure and pseudoTime functions. Then, the solution is obtained for constant-well-rate condition. This is followed by employing the superposition theorem to account for variable well pressure/rate conditions, resulting in definition of two-phase Material-Balance pseudoTime. The solution developed here is coupled with an appropriate Material-Balance equation and used to estimate the average reservoir pressure and original gas in place from analyzing production data. The dependency of relative permeability on capillary number and non-Darcy flow is included in the formulation. Verification of the proposed method is obtained with the analysis of synthetic production data using a series of fine-grid compositional numerical simulations over a typical range of gas/condensate-reservoir parameters.
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Analyzing the Well Production Data of Composite Dual Porosity Single Permeability Oil Reservoirs
Petroleum Science and Technology, 2011Co-Authors: Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Abstract Analyzing well production data is one of the important methods for estimating reservoir parameters such as hydrocarbon in place. Recent techniques rely on the use of Material Balance Time to account for variable operating conditions. Many dual porosity reservoirs can be modeled by a composite reservoir. So production data analysis of composite dual porosity single permeability reservoirs is of great interest. Apparently, modern methods have not been applied to complex reservoir models such as composite dual porosity single permeability reservoirs. So the purpose of this article is to analyze production data of such reservoirs with the use of Material Balance Time function. In the first step, a Material Balance Time function is defined in the same way as the single porosity reservoirs and its applicability is confirmed by converting a constant well pressure solution to a constant well rate solution with the use of this Time function. It should be noted that the available type curve matching method...
Mohammadhossein Heidari Sureshjani - One of the best experts on this subject based on the ideXlab platform.
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A new approach for analysis of production data from constant production rate wells in gas condensate reservoirs
Journal of Natural Gas Science and Engineering, 2014Co-Authors: Milad Arabloo, Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Abstract Production data analysis provides key parameters to a series of reservoir engineering calculations such as reserve estimation, inflow performance calculations, and well production forecast. Although techniques of production data analysis for oil and dry gas reservoirs have advanced significantly over the past few decades, application of these techniques for analyzing production data of gas condensate reservoirs has not been fully studied despite its great practical importance. In this work, a simple yet accurate methodology is presented for reliable estimation of initial gas in place and average reservoir pressure in gas condensate reservoirs. We define new pseudopressure and Material Balance Time functions suitable for gas condensate systems. According to our observations, a Cartesian plot of modified normalized pseudopressure versus modified Material Balance pseudoTime of gas condensate production data yields three distinct regions. In this study we will show that the middle region is unusable and should be distinguished and removed from the analysis. The required input data are bottom hole flowing pressures, gas and condensate production rates, and constant volume depletion (CVD) test data. This study provides example analyses and establishes guidelines for the analysis and interpretation of long term production data in gas condensate reservoirs using developed Cartesian plot.
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A New Model for Modern Production-Decline Analysis of Gas/Condensate Reservoirs
Journal of Canadian Petroleum Technology, 2011Co-Authors: Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Modern production-decline analysis is a robust technique for analysis of production data from a well under variable operating conditions. It uses production rates and flowing pressures to provide reliable estimates of recoverable reserves and fluid in place. The mathematics behind this technique is similar to that of pressure-transient theory; however, the focus is different. It deals with long-term variable production data instead of short-term constant-rate transient data. Using modern decline analysis for two-phase-flow conditions (e.g., gas/condensate reservoirs) is under question because of the single-phase-flow assumption in the development of the "Material-Balance Time" function. This is a Time function that converts any decline (e.g., exponential decline) to harmonic decline to account for variable operating conditions. The purpose of this work is to develop a model to use the concepts of modern techniques for analyzing production data of single-porosity gas/condensate reservoirs. For this purpose, the governing flow equation is linearized, using appropriately defined pseudopressure and pseudoTime functions. Then, the solution is obtained for constant-well-rate condition. This is followed by employing the superposition theorem to account for variable well pressure/rate conditions, resulting in definition of two-phase Material-Balance pseudoTime. The solution developed here is coupled with an appropriate Material-Balance equation and used to estimate the average reservoir pressure and original gas in place from analyzing production data. The dependency of relative permeability on capillary number and non-Darcy flow is included in the formulation. Verification of the proposed method is obtained with the analysis of synthetic production data using a series of fine-grid compositional numerical simulations over a typical range of gas/ condensate-reservoir parameters.
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A New Model for Modern Production-Decline Analysis of Gas/Condensate Reservoirs
Journal of Canadian Petroleum Technology, 2011Co-Authors: Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Summary Modern production-decline analysis is a robust technique for analysis of production data from a well under variable operating conditions. It uses production rates and flowing pressures to provide reliable estimates of recoverable reserves and fluid in place. The mathematics behind this technique is similar to that of pressure-transient theory; however, the focus is different. It deals with long-term variable production data instead of short-term constant-rate transient data. Using modern decline analysis for two-phase-flow conditions (e.g., gas/condensate reservoirs) is under question because of the single-phase-flow assumption in the development of a "Material-Balance Time" function. This is a Time function that converts any decline (e.g., exponential decline) to harmonic decline to account for variable operating conditions. The purpose of this work is to develop a model to use the concepts of modern techniques for analyzing production data of single-porosity gas/condensate reservoirs. For this purpose, the governing flow equation is linearized, using appropriately defined pseudopressure and pseudoTime functions. Then, the solution is obtained for constant-well-rate condition. This is followed by employing the superposition theorem to account for variable well pressure/rate conditions, resulting in definition of two-phase Material-Balance pseudoTime. The solution developed here is coupled with an appropriate Material-Balance equation and used to estimate the average reservoir pressure and original gas in place from analyzing production data. The dependency of relative permeability on capillary number and non-Darcy flow is included in the formulation. Verification of the proposed method is obtained with the analysis of synthetic production data using a series of fine-grid compositional numerical simulations over a typical range of gas/condensate-reservoir parameters.
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Analyzing the Well Production Data of Composite Dual Porosity Single Permeability Oil Reservoirs
Petroleum Science and Technology, 2011Co-Authors: Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Abstract Analyzing well production data is one of the important methods for estimating reservoir parameters such as hydrocarbon in place. Recent techniques rely on the use of Material Balance Time to account for variable operating conditions. Many dual porosity reservoirs can be modeled by a composite reservoir. So production data analysis of composite dual porosity single permeability reservoirs is of great interest. Apparently, modern methods have not been applied to complex reservoir models such as composite dual porosity single permeability reservoirs. So the purpose of this article is to analyze production data of such reservoirs with the use of Material Balance Time function. In the first step, a Material Balance Time function is defined in the same way as the single porosity reservoirs and its applicability is confirmed by converting a constant well pressure solution to a constant well rate solution with the use of this Time function. It should be noted that the available type curve matching method...
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An analytical model for production data analysis of under saturated oil reservoirs subjected to edge aquifer
Journal of Petroleum Science and Engineering, 2011Co-Authors: Mohammadhossein Heidari Sureshjani, Shahab GeramiAbstract:Abstract Analysis of production data is an important method for estimating recoverable reserves and probable life of the reservoirs. Robust techniques for analysis of production data have been developed and widely used for many years. These methods range from the traditional Arps decline method to modern production data analysis. The most recent techniques are based on Material Balance Time to account for variable operating conditions. In these methods, production rate and flowing bottom hole pressure must be known. A major limitation of many existing modern techniques is volumetric assumption of the reservoir. This paper presents a new model that accounts for non-volumetric effects of edge aquifers on production data analysis of single phase oil reservoirs by defining a new Material Balance Time function. This new Time function and Material Balance Time help us to introduce flowing Material Balance (FMB) equations for such reservoirs. Validity of these equations is justified using analytical solutions. For development of analytical solutions, special simplifying assumptions are considered. To justify these assumptions, comparison is made using a commercial numerical reservoir simulator across some ranges of reservoir parameters. Furthermore, based on the validated FMB equations and obtained analytical flow equations, specific procedures are developed for parameter estimation of such reservoirs. The use of these procedures in estimation of oil in place and reservoir external radius is demonstrated using synthetic examples. On the basis of the considered assumptions, the proposed procedures cannot be applied to multi-phase flow conditions, reservoirs with other types of aquifer (such as bottom aquifer), and gas reservoirs. We also show that the given FMB equations are applicable for any irregularly shaped reservoir which is partially contacted with a non-cylindrical limited edge aquifer. For such reservoir geometries, numerical solution is used for justification. This is followed by introducing a simple equation for predicting average reservoir pressure.
Chunlan Zhao - One of the best experts on this subject based on the ideXlab platform.
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a modified blasingame production analysis method for vertical wells considering the quadratic gradient term
Energies, 2019Co-Authors: Qiao Zheng, Chunlan ZhaoAbstract:Fluid flow in actual oil reservoirs is consistent with Material Balance, which should be described by the nonlinear governing equation, including the quadratic gradient term (QGT). Nonetheless, the widely-used Blasingame production decline analysis (BPDA) is established based on the conventional governing equation neglecting the QGT, which leads to some errors in the interpretation of production data under some conditions, such as wells producing at a large drawdown pressure. This work extends BPDA to incorporate the effect of the QGT by modifying Material Balance Time and normalized rate functions. The step-by-step procedure for the proposed production decline analysis (PPDA) is presented and compared with that for BPDA. The simulated cases for various production scenarios are used to validate PPDA. A field case is employed to show the applicability of PPDA in practice. Comparisons between the results obtained by BPDA and PPDA are analyzed in detail. It is found that BPDA overestimates the permeability and original oil-in-place, while PPDA works well. Compared with BPDA, PPDA can be employed to obtain more accurate original oil-in-place and reservoir properties, especially when wells produce at a large drawdown pressure.
Hongliang Huang - One of the best experts on this subject based on the ideXlab platform.
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A practical method for production data analysis from multistage fractured horizontal wells in shale gas reservoirs
Fuel, 2016Co-Authors: Linsong Cheng, Shijun Huang, Pin Jia, Jin Zhang, Xiang Lan, Hongliang HuangAbstract:Abstract Shale gas reservoirs are characterized by gas adsorption in matrix and complex fracture networks after hydraulic fracturing stimulation, and the properties of which cannot be measured through existing methods. Many linear flow models have been proposed to interpret these properties, however the nonlinearity of desorption and gas compressibility is often neglected when analyzing production data. Moreover, the production rate and bottom hole pressure (BHP) are usually variable, while the control mode in analytical models is either at constant production rate or BHP. Therefore, the nonlinearity should be considered when interpreting production data, and the problem of variable rate and BHP remains to be solved. In this paper, a comprehensive method for analysis of production data with variable rate for multistage fractured horizontal wells in shale gas reservoirs has been put forward, in which the nonlinearity of desorption and compressibility is considered. The classical tri-linear flow model is modified by incorporating desorption in the matrix. New type curves are developed incorporating normalized rate, integration of the rate and derivative of the integration against pseudo-Time. To analyze production data with nonlinear desorption and compressibility, modified Material Balance equation and Material Balance Time are applied to process production data. If the production data of a real shale reservoir is given, the half-length and the permeability of the hydraulic fractures, the permeability of the stimulated reservoir volume can be determined with this method. Finally, a field case is used to demonstrate this method for production data analysis.
Craig Emmitt Roco - One of the best experts on this subject based on the ideXlab platform.
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Reservoir characterization of the Upper and Lower Repetto reservoirs of the Santa Clara field-federal waters, offshore California
2000Co-Authors: Craig Emmitt RocoAbstract:This thesis presents the characterization of the Upper and Lower Repetto reservoirs of the Santa Clara field, which lies seven miles offshore of Ventura County, California. The approaches that we adopted for this reservoir characterization are based on the analysis of field production data. These reservoir characterization approaches include: The application of the Fetkovich/McCray decline type curve to estimate original oil-in-place, drainage area, flow capacity, and a skin factor for each well. This approach requires converting the field production data for each well to dimensionless decline flowrate, dimensionless rate integral, and dimensionless rate integral-derivative functions. These functions are then simultaneously plotted against dimensionless decline Time so that a unique match of these plots can be obtained using the Fetkovich/McCray decline type curve (in this research, data conversion and type curve matching are performed using a software package). The analysis of plots of reciprocal production rate versus Material Balance Time to estimate "movable" or recoverable oil reserves. This new Material Balance approach is used in conjunction with a semi-analytical method of graphical analysis (pressure drop normalized rate versus cumulative oil production), which also provides estimates of recoverable oil reserves. Together, these plotting techniques provide good estimates of the estimated ultimate recovery for each well. Our approaches for the analysis of field production data allow us to provide recovery factors for each well (using our estimates of original oil-in-place and estimated ultimate recovery). Furthermore, we were able to generate maps of original oil-in-place, estimated ultimate recovery, flow capacity, and permeability for both the Upper and Lower Repetto reservoirs.