The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Xinzhe Shen - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of Water-Influx Locations of Horizontal Well Subject to Bottom-Water Drive through Well-Testing Analysis
Geofluids, 2018Co-Authors: Jiazheng Qin, Shiqing Cheng, Le Luo, Xinzhe ShenAbstract:Horizontal well (HW) has been widely applied to enhance well productivity and prevent water coning in the Anisotropic Reservoir subject to bottom-water drive. However, the water-cut increases quickly after only one or two years’ production in China while oil recovery still keeps at a very low level. It becomes a major challenge to effectively estimate production distribution and diagnose water-influx locations. Ignoring the effect of nonuniform production distribution along wellbore on pressure response may cause erroneous results especially for water-influx location determination. This paper developed an analytical method to determine nonuniform production distribution and estimate water-influx sections through well-testing analysis. Each HW is divided into multiple producing segments (PS) with variable parameters (e.g., location, production, length, and skin factor) in this model. By using Green’s functions and the Newman-product method, the novel transient pressure solutions of an HW can be obtained in the Anisotropic Reservoir with bottom-water drive. Secondly, the influences of nonuniform production-distribution on type curves are investigated by comparing the multisegment model (MSM) with the whole-segment model (WSM). Results indicate that the method proposed in this paper enables petroleum operators to interpret parameters of Reservoir and HW more accurately by using well-testing interpretation on the basis of bottom-hole pressure data and further estimate water-influx sections and nonproducing segments. Additionally, relevant measures can be conducted to enhance oil production, such as water controlling for water-breakthrough segments and stimulation treatments for nonproducing locations.
Guoqiang Xing - One of the best experts on this subject based on the ideXlab platform.
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Productivity analysis for a horizontal well with multiple reorientation fractures in an Anisotropic Reservoir
Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 2020Co-Authors: Mingxian Wang, Guoqiang Xing, Zifei Fan, Lun Zhao, Wenqi Zhao, Chengqian TanAbstract:Reorientation fractures may be formed in soft and shallow formations during fracturing stimulation and then affect well productivity. The principal focus of this study is on the productivity analysis for a horizontal well with multiple reorientation fractures in an Anisotropic Reservoir. Combining the nodal analysis technique and fracture-wing method, a semi-analytical model for a horizontal well with multiple finite-conductivity reorientation fractures was established to calculate its dimensionless productivity index and derivative for production evaluation. A classic case in the literature was selected to verify the accuracy of our semi-analytical solution and the verification indicates this new solution is reliable. Results show that for a fixed fracture configuration the dimensionless productivity index of the proposed model first goes up and then remains constant with the increase of fracture conductivity, and optimal fracture conductivity can be determined on derivative curves. Strong permeability anisotropy is a negative factor for well production and the productivity index gradually decreases with the increase of Anisotropic factor. As principal fracture angle goes up, horizontal well’s productivity index increases correspondingly. However, the effect of reoriented fracture angle on the productivity index is not as strong as that of principal fracture angle. When reoriented fracture angle is smaller than principal fracture angle, reoriented factor should be as low as possible to achieve optimal productivity index. Meanwhile, well productivity index rises up with the increase of fracture number and fracture spacing, but the horizontal well has optimal reorientation fracture number and fracture spacing to get the economical productivity. Furthermore, the influence of the rotation of one central reorientation fracture on productivity index is weaker than that caused by the rotation of one external reorientation fracture. In addition, the asymmetrical distribution of one or more reorientation fractures slightly affects the productivity index when fracture conductivity is high enough.
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Pseudo-Steady-State Parameters for a Well Penetrated by a Fracture with an Azimuth Angle in an Anisotropic Reservoir
Energies, 2019Co-Authors: Guoqiang Xing, Mingxian Wang, Jiangyan Dong, Wenqi ZhaoAbstract:Many oil wells in closed Reservoirs continue to produce in the pseudo-steady-state flow regime for a long time. The principal objective of this work is to investigate the characteristics of two key pseudo-steady-state parameters—pseudo-steady-state constant (bDpss) and pseudo-skin factor (S)—for a well penetrated by a fracture with an azimuth angle (θ) in an Anisotropic Reservoir. Firstly, a general analytical pressure solution for a finite-conductivity fracture with or without an azimuth angle in an Anisotropic rectangular Reservoir was developed by using the point-source function and spatial integral method, and two typical cases were employed to verify this solution. Secondly, with the asymptotic analysis method, the expressions of pseudo-steady-state constant and pseudo-skin factor were obtained on the basis of their definitions, and the effects of permeability anisotropy, fracture azimuth angle, fracture conductivity and Reservoir shape on them were discussed in detail. Results show that all the bDpss-θ and S-θ curves are symmetric around the vertical line, θ = 90° and form a hump or groove shape. The optimized fracture direction in an Anisotropic Reservoir is perpendicular to the principal permeability axis. Furthermore, a new formula to calculate pseudo-skin factor was successfully proposed based on these two parameters’ relationship. Finally, as an application of pseudo-steady-state constant, a set of Blasingame format rate decline curves for the proposed model were established.
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A semi-analytical model for pressure transient analysis of hydraulic reorientation fracture in an Anisotropic Reservoir
Journal of Petroleum Science and Engineering, 2019Co-Authors: Guoqiang Xing, Yudong Cui, Baohua Wang, Mingyu Shi, Mingxian WangAbstract:Abstract Fracture reorientation can be used to increase well production in an Anisotropic Reservoir. The principal focus of this work is on the transient pressure analysis for a hydraulic reorientation fracture in a rectangular Anisotropic Reservoir. By employing the nodal analysis technique, a set of diffusivity equations are developed to describe the flow in a hydraulic reorientation fracture. Then, a semi-analytical solution is obtained by coupling the point source solution and the discrete fracture solution. The validation of this work is demonstrated by comparing the previous study and the numerical simulation for a reorientation fracture. Five typical flow regimes can be observed on this model's transient response. Flux along the reorientation fracture is also generated to analyze the flux distribution at different time. Furthermore, type curves are obtained to investigate the effect of the key parameters on the transient flow behavior, including principal fracture angle, reoriented fracture angle, permeability anisotropy, fracture conductivity and fracture length ratio. For a rectangular Anisotropic Reservoir, the influence of principal fracture angle, permeability anisotropy and fracture conductivity on the type curves is concentrated in the early-time and middle-time periods, and reoriented fracture angle and fracture length ratio mainly affect the formation linear flow regime.
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Pressure-transient analysis for a vertically fractured well at an arbitrary azimuth in a rectangular Anisotropic Reservoir
Journal of Petroleum Science and Engineering, 2017Co-Authors: Xiaodong Wang, Guoqiang Xing, Junlei WangAbstract:Abstract The principal focus of this paper is on pressure-transient analysis for a finite-conductivity fracture at an arbitrary azimuth in a rectangular Anisotropic Reservoir. An analytical solution is derived by spatial integration of point-source along the direction of the fracture for a fracture at an arbitrary azimuth in a rectangular Reservoir. Furthermore, type curves are generated to investigate the influence of the main parameters on transient pressure behavior, including permeability anisotropy, azimuth of the fracture, Reservoir's outer boundary, and fracture conductivity. Strong effects of horizontal permeability anisotropy and azimuth of a fracture on transient responses can be observed. The more the fracture deviates from the direction of maximum horizontal permeability, lesser the drawdown needed to maintain constant flow rate. Therefore, it seems that the optimum orientation for the hydraulic fracture is perpendicular to the direction of maximum horizontal permeability. Outer boundary size dominates pseudo-steady-state flow and aspect ratio mainly affects the periods of radial flow and compound-linear flow. The existence and duration of bilinear flow and formation linear flow are mainly determined by dimensionless fracture conductivity. This paper provides a theoretical basis for well pattern deployment and fracture configuration in Anisotropic Reservoirs.
Mingxian Wang - One of the best experts on this subject based on the ideXlab platform.
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Productivity analysis for a horizontal well with multiple reorientation fractures in an Anisotropic Reservoir
Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 2020Co-Authors: Mingxian Wang, Guoqiang Xing, Zifei Fan, Lun Zhao, Wenqi Zhao, Chengqian TanAbstract:Reorientation fractures may be formed in soft and shallow formations during fracturing stimulation and then affect well productivity. The principal focus of this study is on the productivity analysis for a horizontal well with multiple reorientation fractures in an Anisotropic Reservoir. Combining the nodal analysis technique and fracture-wing method, a semi-analytical model for a horizontal well with multiple finite-conductivity reorientation fractures was established to calculate its dimensionless productivity index and derivative for production evaluation. A classic case in the literature was selected to verify the accuracy of our semi-analytical solution and the verification indicates this new solution is reliable. Results show that for a fixed fracture configuration the dimensionless productivity index of the proposed model first goes up and then remains constant with the increase of fracture conductivity, and optimal fracture conductivity can be determined on derivative curves. Strong permeability anisotropy is a negative factor for well production and the productivity index gradually decreases with the increase of Anisotropic factor. As principal fracture angle goes up, horizontal well’s productivity index increases correspondingly. However, the effect of reoriented fracture angle on the productivity index is not as strong as that of principal fracture angle. When reoriented fracture angle is smaller than principal fracture angle, reoriented factor should be as low as possible to achieve optimal productivity index. Meanwhile, well productivity index rises up with the increase of fracture number and fracture spacing, but the horizontal well has optimal reorientation fracture number and fracture spacing to get the economical productivity. Furthermore, the influence of the rotation of one central reorientation fracture on productivity index is weaker than that caused by the rotation of one external reorientation fracture. In addition, the asymmetrical distribution of one or more reorientation fractures slightly affects the productivity index when fracture conductivity is high enough.
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Pseudo-Steady-State Parameters for a Well Penetrated by a Fracture with an Azimuth Angle in an Anisotropic Reservoir
Energies, 2019Co-Authors: Guoqiang Xing, Mingxian Wang, Jiangyan Dong, Wenqi ZhaoAbstract:Many oil wells in closed Reservoirs continue to produce in the pseudo-steady-state flow regime for a long time. The principal objective of this work is to investigate the characteristics of two key pseudo-steady-state parameters—pseudo-steady-state constant (bDpss) and pseudo-skin factor (S)—for a well penetrated by a fracture with an azimuth angle (θ) in an Anisotropic Reservoir. Firstly, a general analytical pressure solution for a finite-conductivity fracture with or without an azimuth angle in an Anisotropic rectangular Reservoir was developed by using the point-source function and spatial integral method, and two typical cases were employed to verify this solution. Secondly, with the asymptotic analysis method, the expressions of pseudo-steady-state constant and pseudo-skin factor were obtained on the basis of their definitions, and the effects of permeability anisotropy, fracture azimuth angle, fracture conductivity and Reservoir shape on them were discussed in detail. Results show that all the bDpss-θ and S-θ curves are symmetric around the vertical line, θ = 90° and form a hump or groove shape. The optimized fracture direction in an Anisotropic Reservoir is perpendicular to the principal permeability axis. Furthermore, a new formula to calculate pseudo-skin factor was successfully proposed based on these two parameters’ relationship. Finally, as an application of pseudo-steady-state constant, a set of Blasingame format rate decline curves for the proposed model were established.
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A semi-analytical model for pressure transient analysis of hydraulic reorientation fracture in an Anisotropic Reservoir
Journal of Petroleum Science and Engineering, 2019Co-Authors: Guoqiang Xing, Yudong Cui, Baohua Wang, Mingyu Shi, Mingxian WangAbstract:Abstract Fracture reorientation can be used to increase well production in an Anisotropic Reservoir. The principal focus of this work is on the transient pressure analysis for a hydraulic reorientation fracture in a rectangular Anisotropic Reservoir. By employing the nodal analysis technique, a set of diffusivity equations are developed to describe the flow in a hydraulic reorientation fracture. Then, a semi-analytical solution is obtained by coupling the point source solution and the discrete fracture solution. The validation of this work is demonstrated by comparing the previous study and the numerical simulation for a reorientation fracture. Five typical flow regimes can be observed on this model's transient response. Flux along the reorientation fracture is also generated to analyze the flux distribution at different time. Furthermore, type curves are obtained to investigate the effect of the key parameters on the transient flow behavior, including principal fracture angle, reoriented fracture angle, permeability anisotropy, fracture conductivity and fracture length ratio. For a rectangular Anisotropic Reservoir, the influence of principal fracture angle, permeability anisotropy and fracture conductivity on the type curves is concentrated in the early-time and middle-time periods, and reoriented fracture angle and fracture length ratio mainly affect the formation linear flow regime.
Jiazheng Qin - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis of Water-Influx Locations of Horizontal Well Subject to Bottom-Water Drive through Well-Testing Analysis
Geofluids, 2018Co-Authors: Jiazheng Qin, Shiqing Cheng, Le Luo, Xinzhe ShenAbstract:Horizontal well (HW) has been widely applied to enhance well productivity and prevent water coning in the Anisotropic Reservoir subject to bottom-water drive. However, the water-cut increases quickly after only one or two years’ production in China while oil recovery still keeps at a very low level. It becomes a major challenge to effectively estimate production distribution and diagnose water-influx locations. Ignoring the effect of nonuniform production distribution along wellbore on pressure response may cause erroneous results especially for water-influx location determination. This paper developed an analytical method to determine nonuniform production distribution and estimate water-influx sections through well-testing analysis. Each HW is divided into multiple producing segments (PS) with variable parameters (e.g., location, production, length, and skin factor) in this model. By using Green’s functions and the Newman-product method, the novel transient pressure solutions of an HW can be obtained in the Anisotropic Reservoir with bottom-water drive. Secondly, the influences of nonuniform production-distribution on type curves are investigated by comparing the multisegment model (MSM) with the whole-segment model (WSM). Results indicate that the method proposed in this paper enables petroleum operators to interpret parameters of Reservoir and HW more accurately by using well-testing interpretation on the basis of bottom-hole pressure data and further estimate water-influx sections and nonproducing segments. Additionally, relevant measures can be conducted to enhance oil production, such as water controlling for water-breakthrough segments and stimulation treatments for nonproducing locations.
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New well pattern optimization methodology in mature low-permeability Anisotropic Reservoirs
Journal of Geophysics and Engineering, 2017Co-Authors: Jiazheng Qin, Yuetian Liu, Yueli Feng, Yao Ding, Liu LiuAbstract:In China, lots of well patterns were designed before people know the principal permeability direction in low-permeability Anisotropic Reservoirs. After several years' production, it turns out that well line direction is unparallel with principal permeability direction. However, traditional well location optimization methods (in terms of the objective function such as NPV and/or ultimate recovery) are inapplicable since wells are not free to move around in mature oilfield. Thus, well pattern optimization (WPO) of mature low-permeability Anisotropic Reservoir is a significant but challenging task since original well pattern (WP) will be distorted and reconstructed due to permeability anisotropy. In this paper, we investigate the destruction and reconstruction of WP when principal permeability direction and well line direction are unparallel. A new methodology was developed to quantitatively optimize well locations of mature large-scale WP through WPO algorithm on the basis of coordinate transformation (i.e. rotating and stretching). For mature oilfield, large-scale WP has been settled, so it is not economically viable to carry out further infill drilling. This paper circumvents the difficulty by combining WPO algorithm with well status (open or shut-in) and schedule adjustment. Finally, this methodology is applied to an example. Cumulative oil production rates of the optimized WP are higher, and water-cut is lower, which highlights the potential of the WPO methodology application in mature large-scale field development projects.
Wenqi Zhao - One of the best experts on this subject based on the ideXlab platform.
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Productivity analysis for a horizontal well with multiple reorientation fractures in an Anisotropic Reservoir
Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 2020Co-Authors: Mingxian Wang, Guoqiang Xing, Zifei Fan, Lun Zhao, Wenqi Zhao, Chengqian TanAbstract:Reorientation fractures may be formed in soft and shallow formations during fracturing stimulation and then affect well productivity. The principal focus of this study is on the productivity analysis for a horizontal well with multiple reorientation fractures in an Anisotropic Reservoir. Combining the nodal analysis technique and fracture-wing method, a semi-analytical model for a horizontal well with multiple finite-conductivity reorientation fractures was established to calculate its dimensionless productivity index and derivative for production evaluation. A classic case in the literature was selected to verify the accuracy of our semi-analytical solution and the verification indicates this new solution is reliable. Results show that for a fixed fracture configuration the dimensionless productivity index of the proposed model first goes up and then remains constant with the increase of fracture conductivity, and optimal fracture conductivity can be determined on derivative curves. Strong permeability anisotropy is a negative factor for well production and the productivity index gradually decreases with the increase of Anisotropic factor. As principal fracture angle goes up, horizontal well’s productivity index increases correspondingly. However, the effect of reoriented fracture angle on the productivity index is not as strong as that of principal fracture angle. When reoriented fracture angle is smaller than principal fracture angle, reoriented factor should be as low as possible to achieve optimal productivity index. Meanwhile, well productivity index rises up with the increase of fracture number and fracture spacing, but the horizontal well has optimal reorientation fracture number and fracture spacing to get the economical productivity. Furthermore, the influence of the rotation of one central reorientation fracture on productivity index is weaker than that caused by the rotation of one external reorientation fracture. In addition, the asymmetrical distribution of one or more reorientation fractures slightly affects the productivity index when fracture conductivity is high enough.
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Pseudo-Steady-State Parameters for a Well Penetrated by a Fracture with an Azimuth Angle in an Anisotropic Reservoir
Energies, 2019Co-Authors: Guoqiang Xing, Mingxian Wang, Jiangyan Dong, Wenqi ZhaoAbstract:Many oil wells in closed Reservoirs continue to produce in the pseudo-steady-state flow regime for a long time. The principal objective of this work is to investigate the characteristics of two key pseudo-steady-state parameters—pseudo-steady-state constant (bDpss) and pseudo-skin factor (S)—for a well penetrated by a fracture with an azimuth angle (θ) in an Anisotropic Reservoir. Firstly, a general analytical pressure solution for a finite-conductivity fracture with or without an azimuth angle in an Anisotropic rectangular Reservoir was developed by using the point-source function and spatial integral method, and two typical cases were employed to verify this solution. Secondly, with the asymptotic analysis method, the expressions of pseudo-steady-state constant and pseudo-skin factor were obtained on the basis of their definitions, and the effects of permeability anisotropy, fracture azimuth angle, fracture conductivity and Reservoir shape on them were discussed in detail. Results show that all the bDpss-θ and S-θ curves are symmetric around the vertical line, θ = 90° and form a hump or groove shape. The optimized fracture direction in an Anisotropic Reservoir is perpendicular to the principal permeability axis. Furthermore, a new formula to calculate pseudo-skin factor was successfully proposed based on these two parameters’ relationship. Finally, as an application of pseudo-steady-state constant, a set of Blasingame format rate decline curves for the proposed model were established.