The Experts below are selected from a list of 32106 Experts worldwide ranked by ideXlab platform
Junlong Zhao - One of the best experts on this subject based on the ideXlab platform.
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In-situ stress distribution and its influence on the coal Reservoir Permeability in the Hancheng area, eastern margin of the Ordos Basin, China
Journal of Natural Gas Science and Engineering, 2019Co-Authors: Junlong Zhao, Dazhen Tang, Wenji Lin, Yong QinAbstract:Abstract During the coalbed methane (CBM) exploration and development, in-situ stress and Permeability are two vital Reservoir evaluation parameters. In this work, with the injection/falloff well test and in-situ stress data of 11 CBM wells in the Hancheng area, eastern margin of the Ordos Basin, China, the distribution of in-situ stress and its influence on the coal Reservoir Permeability were investigated. Results show that the maximum (SH, 10.80–53.84 MPa) and minimum horizontal (Sh, 9.96–31.88 MPa), and vertical principal stresses (Sv, 14.37–36.46 MPa) increase with the increasing burial depth. However, the coal Reservoir Permeability (0.01–0.54 mD) shows a decreasing tendency accompanied by increasing stresses. Three stress fields (I, II, and III) between 532.28 and 1350.55 m could be divided: I is in a compression zone (〈700 m, SH〉Sh ≈ Sv, reverse or strike-slip stress regimes); II is in a tension zone (700–850 m, Sv > SH > Sh, normal stress regime); III is in a compression zone again (>850 m, SH > Sv > Sh, strike-slip stress regime). The top-down in-situ stress regimes result in a “decreasing - increasing - decreasing” Permeability variation. Meanwhile, the lateral stress coefficient, stress ratios decreased slowly while the Reservoir pressures and temperatures show a positive correlation with increasing burial depth.
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Characteristic of In Situ Stress and Its Control on the Coalbed Methane Reservoir Permeability in the Eastern Margin of the Ordos Basin, China
Rock Mechanics and Rock Engineering, 2016Co-Authors: Junlong Zhao, Dazhen Tang, Hao Xu, Yong Li, Song LiAbstract:Coalbed methane (CBM) development faces many challenges, among which in situ stress and Permeability are two of the most important and fundamental factors. Knowledge of the characteristics of these factors is crucial to CBM exploration and development. Based on measured injection/falloff and in situ stress well test data of 55 CBM wells in the eastern margin of the Ordos Basin, correlations between parameters including initial Reservoir pressure, in situ stress, lateral stress coefficient, well test Permeability, and burial depth were determined. The distribution of in situ stress was analyzed systematically and its influence on Permeability was also addressed. The results indicate that the maximum horizontal principal stress (σH 10.13–37.84 MPa, average 22.50 MPa), minimum horizontal principal stress (σh 6.98–26.88 MPa, average 15.04 MPa) and vertical stress (σv 12.30–35.72 MPa, average 22.48 MPa) all have positive correlations with coal burial depth. Stress ratios (σH/σh, σH/σv, and σh/σv) and lateral stress coefficient slowly attenuated with depth. With increase of horizontal principal stresses, coal Reservoir Permeability (0.01–3.33 mD, average 0.65 mD) decreases. The Permeability variation is basically consistent with change of stress state at a certain burial depth, the essence of which is the deformation and destruction of coal pore structures under the action of stresses. Three types of stress fields exist in the area: in the shallow coal seam at burial depths σv > σh), with average Permeability 0.89 mD; from 700 to 1000 m depths, there is a stress transition zone (σH ≈ σv > σh) with average Permeability 0.73 mD; in the deep coal seam with burial depths >1000 m, the vertical principal stress is dominant, demonstrating a normal stress regime (σv > σH > σh) with average Permeability 0.11 mD.
Yong Qin - One of the best experts on this subject based on the ideXlab platform.
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In-situ stress distribution and its influence on the coal Reservoir Permeability in the Hancheng area, eastern margin of the Ordos Basin, China
Journal of Natural Gas Science and Engineering, 2019Co-Authors: Junlong Zhao, Dazhen Tang, Wenji Lin, Yong QinAbstract:Abstract During the coalbed methane (CBM) exploration and development, in-situ stress and Permeability are two vital Reservoir evaluation parameters. In this work, with the injection/falloff well test and in-situ stress data of 11 CBM wells in the Hancheng area, eastern margin of the Ordos Basin, China, the distribution of in-situ stress and its influence on the coal Reservoir Permeability were investigated. Results show that the maximum (SH, 10.80–53.84 MPa) and minimum horizontal (Sh, 9.96–31.88 MPa), and vertical principal stresses (Sv, 14.37–36.46 MPa) increase with the increasing burial depth. However, the coal Reservoir Permeability (0.01–0.54 mD) shows a decreasing tendency accompanied by increasing stresses. Three stress fields (I, II, and III) between 532.28 and 1350.55 m could be divided: I is in a compression zone (〈700 m, SH〉Sh ≈ Sv, reverse or strike-slip stress regimes); II is in a tension zone (700–850 m, Sv > SH > Sh, normal stress regime); III is in a compression zone again (>850 m, SH > Sv > Sh, strike-slip stress regime). The top-down in-situ stress regimes result in a “decreasing - increasing - decreasing” Permeability variation. Meanwhile, the lateral stress coefficient, stress ratios decreased slowly while the Reservoir pressures and temperatures show a positive correlation with increasing burial depth.
Dazhen Tang - One of the best experts on this subject based on the ideXlab platform.
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In-situ stress distribution and its influence on the coal Reservoir Permeability in the Hancheng area, eastern margin of the Ordos Basin, China
Journal of Natural Gas Science and Engineering, 2019Co-Authors: Junlong Zhao, Dazhen Tang, Wenji Lin, Yong QinAbstract:Abstract During the coalbed methane (CBM) exploration and development, in-situ stress and Permeability are two vital Reservoir evaluation parameters. In this work, with the injection/falloff well test and in-situ stress data of 11 CBM wells in the Hancheng area, eastern margin of the Ordos Basin, China, the distribution of in-situ stress and its influence on the coal Reservoir Permeability were investigated. Results show that the maximum (SH, 10.80–53.84 MPa) and minimum horizontal (Sh, 9.96–31.88 MPa), and vertical principal stresses (Sv, 14.37–36.46 MPa) increase with the increasing burial depth. However, the coal Reservoir Permeability (0.01–0.54 mD) shows a decreasing tendency accompanied by increasing stresses. Three stress fields (I, II, and III) between 532.28 and 1350.55 m could be divided: I is in a compression zone (〈700 m, SH〉Sh ≈ Sv, reverse or strike-slip stress regimes); II is in a tension zone (700–850 m, Sv > SH > Sh, normal stress regime); III is in a compression zone again (>850 m, SH > Sv > Sh, strike-slip stress regime). The top-down in-situ stress regimes result in a “decreasing - increasing - decreasing” Permeability variation. Meanwhile, the lateral stress coefficient, stress ratios decreased slowly while the Reservoir pressures and temperatures show a positive correlation with increasing burial depth.
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Characteristic of In Situ Stress and Its Control on the Coalbed Methane Reservoir Permeability in the Eastern Margin of the Ordos Basin, China
Rock Mechanics and Rock Engineering, 2016Co-Authors: Junlong Zhao, Dazhen Tang, Hao Xu, Yong Li, Song LiAbstract:Coalbed methane (CBM) development faces many challenges, among which in situ stress and Permeability are two of the most important and fundamental factors. Knowledge of the characteristics of these factors is crucial to CBM exploration and development. Based on measured injection/falloff and in situ stress well test data of 55 CBM wells in the eastern margin of the Ordos Basin, correlations between parameters including initial Reservoir pressure, in situ stress, lateral stress coefficient, well test Permeability, and burial depth were determined. The distribution of in situ stress was analyzed systematically and its influence on Permeability was also addressed. The results indicate that the maximum horizontal principal stress (σH 10.13–37.84 MPa, average 22.50 MPa), minimum horizontal principal stress (σh 6.98–26.88 MPa, average 15.04 MPa) and vertical stress (σv 12.30–35.72 MPa, average 22.48 MPa) all have positive correlations with coal burial depth. Stress ratios (σH/σh, σH/σv, and σh/σv) and lateral stress coefficient slowly attenuated with depth. With increase of horizontal principal stresses, coal Reservoir Permeability (0.01–3.33 mD, average 0.65 mD) decreases. The Permeability variation is basically consistent with change of stress state at a certain burial depth, the essence of which is the deformation and destruction of coal pore structures under the action of stresses. Three types of stress fields exist in the area: in the shallow coal seam at burial depths σv > σh), with average Permeability 0.89 mD; from 700 to 1000 m depths, there is a stress transition zone (σH ≈ σv > σh) with average Permeability 0.73 mD; in the deep coal seam with burial depths >1000 m, the vertical principal stress is dominant, demonstrating a normal stress regime (σv > σH > σh) with average Permeability 0.11 mD.
Zhufeng Fang - One of the best experts on this subject based on the ideXlab platform.
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An Uncertainty Quantification Framework for Studying the Effect of Spatial Heterogeneity in Reservoir Permeability on CO_2 Sequestration
Mathematical Geosciences, 2013Co-Authors: Dave W. Engel, Yilin Fang, Zhufeng FangAbstract:A new uncertainty quantification framework is adopted for carbon sequestration to evaluate the effect of spatial heterogeneity of Reservoir Permeability on CO_2 migration. Sequential Gaussian simulation is used to generate multiple realizations of Permeability fields with various spatial statistical attributes. In order to deal with the computational difficulties, the following ideas/approaches are integrated. First, different efficient sampling approaches (probabilistic collocation, quasi-Monte Carlo, and adaptive sampling) are used to reduce the number of forward calculations, explore effectively the parameter space, and quantify the input uncertainty. Second, a scalable numerical simulator, extreme-scale Subsurface Transport Over Multiple Phases, is adopted as the forward modeling simulator for CO_2 migration. The framework has the capability to quantify input uncertainty, generate exploratory samples effectively, perform scalable numerical simulations, visualize output uncertainty, and evaluate input-output relationships. The framework is demonstrated with a given CO_2 injection scenario in heterogeneous sandstone Reservoirs. Results show that geostatistical parameters for Permeability have different impacts on CO_2 plume radius: the mean parameter has positive effects at the top layers, but affects the bottom layers negatively. The variance generally has a positive effect on the plume radius at all layers, particularly at middle layers, where the transport of CO_2 is highly influenced by the subsurface heterogeneity structure. The anisotropy ratio has weak impacts on the plume radius, but affects the shape of the CO_2 plume.
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An Uncertainty Quantification Framework for Studying the Effect of Spatial Heterogeneity in Reservoir Permeability on CO2 Sequestration
Mathematical Geosciences, 2013Co-Authors: Zhangshuan Hou, Yilin Fang, David Engel, Guang Lin, Zhufeng FangAbstract:A new uncertainty quantification framework is adopted for carbon sequestration to evaluate the effect of spatial heterogeneity of Reservoir Permeability on CO2 migration. Sequential Gaussian simulation is used to generate multiple realizations of Permeability fields with various spatial statistical attributes. In order to deal with the computational difficulties, the following ideas/approaches are integrated. First, different efficient sampling approaches (probabilistic collocation, quasi-Monte Carlo, and adaptive sampling) are used to reduce the number of forward calculations, explore effectively the parameter space, and quantify the input uncertainty. Second, a scalable numerical simulator, extreme-scale Subsurface Transport Over Multiple Phases, is adopted as the forward modeling simulator for CO2 migration. The framework has the capability to quantify input uncertainty, generate exploratory samples effectively, perform scalable numerical simulations, visualize output uncertainty, and evaluate input-output relationships. The framework is demonstrated with a given CO2 injection scenario in heterogeneous sandstone Reservoirs. Results show that geostatistical parameters for Permeability have different impacts on CO2 plume radius: the mean parameter has positive effects at the top layers, but affects the bottom layers negatively. The variance generally has a positive effect on the plume radius at all layers, particularly at middle layers, where the transport of CO2 is highly influenced by the subsurface heterogeneity structure. The anisotropy ratio has weak impacts on the plume radius, but affects the shape of the CO2 plume.
Yuchao Zeng - One of the best experts on this subject based on the ideXlab platform.
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Orthogonal Test Analysis on Conditions Affecting Electricity Generation Performance of an Enhanced Geothermal System at Yangbajing Geothermal Field
Energies, 2017Co-Authors: Yuchao Zeng, Liansheng Tang, Jing Song, Yifei CaoAbstract:The main conditions affecting electricity generation performance of an enhanced geothermal system (EGS) include Reservoir porosity, Reservoir Permeability, rock heat conductivity, water production rate and injection temperature. Presently there is lack of systematic research the relative importance of the five aforementioned conditions. The orthogonal test method is a statistical approach to analyze multi-factor and multi-level influence on system performance. In this work, based on the geological data at Yangbajing geothermal field, we analyzed the five conditions affecting the electricity generation performance of EGS, and ranked the relative importance of the five factors. The results show that the order of the relative importance of the conditions on electric power is water production rate > injection temperature > Reservoir porosity > rock heat conductivity > Reservoir Permeability; the order of the relative importance of the conditions on Reservoir impedance is Reservoir Permeability > injection temperature > water production rate > Reservoir porosity > rock heat conductivity; the order of the relative importance of the conditions on pump power is water production rate > Reservoir Permeability > injection temperature > Reservoir porosity > rock heat conductivity, and; the order of the relative importance of the conditions on energy efficiency is water production rate > Reservoir Permeability > Reservoir porosity > injection temperature > rock heat conductivity. The construction of an EGS Reservoir should be located at a formation with higher Reservoir porosity or rock heat conductivity, while the determination of Reservoir Permeability, water production rate and injection temperature should be based on the comprehensive target.
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Analysis of influencing factors of production performance of enhanced geothermal system: A case study at Yangbajing geothermal field
Energy, 2017Co-Authors: Yuchao Zeng, Liansheng Tang, Yifei CaoAbstract:Deep geological exploration indicates that there is a high-temperature fractured granite Reservoir at depth of 950–1350 m in well ZK4001 in the north of Yangbajing geothermal field, with an average temperature of 248 °C and a pressure within 8.01–11.57 MPa. In this work we established a conceptual and numerical model of this granite Reservoir, evaluated heat production and electricity generation potential from this fractured Reservoir by means of numerical simulation, and analyzed main factors affecting the heat production performance. The results indicate that in the reference case the system attains an electric power of 29.5–25.1 MW, a Reservoir impedance of 0.12–0.21MPa/(kg/s), a pump power of 0.7–1.6 MW and an energy efficiency of 41.1–15.7 during a 50 year period. Main factors affecting the electric power are water production rate and injection temperature. Main factors affecting the Reservoir impedance are the Reservoir Permeability, the water production rate and the injection temperature. Main factors affecting the pump power are the Reservoir Permeability, the water production rate and the injection temperature. Main factors affecting the energy efficiency are the Reservoir Permeability, the water production rate and the injection temperature. Within certain ranges main measures to improve the Reservoir performance are to increase the Reservoir Permeability or adopt more reasonable water production rate and injection temperature.
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numerical simulation of electricity generation potential from fractured granite Reservoir through vertical wells at yangbajing geothermal field
Energy, 2016Co-Authors: Yuchao Zeng, Jiemin Zhan, Nengyou WuAbstract:Yangbajing geothermal field is the first high-temperature hydrothermal convective geothermal system in China. Research and development of the deep fractured granite Reservoir is of great importance for capacity expanding and sustaining of the ground power plant. The geological exploration found that there is a fractured granite heat Reservoir at depth of 950–1350 m in well ZK4001 in the north of the geothermal field, with an average temperature of 248 °C and a pressure of 8.01–11.57 MPa. In this work, electricity generation potential and its dependent factors from this fractured granite Reservoir by water circulating through vertical wells are numerically investigated. The results indicate that the vertical well system attains an electric power of 16.8–14.7 MW, a Reservoir impedance of 0.29–0.46 MPa/(kg/s) and an energy efficiency of about 29.6–12.8 during an exploiting period of 50 years under reference conditions, showing good heat production performance. The main parameters affecting the electric power are water production rate and injection temperature. The main parameters affecting Reservoir impedance are Reservoir Permeability, injection temperature and water production rate. The main parameters affecting the energy efficiency are Reservoir Permeability, injection temperature and water production rate. Higher Reservoir Permeability or more reasonable injection temperature or water production rate within certain ranges will be favorable for improving the electricity generation performance.
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numerical simulation of heat production potential from hot dry rock by water circulating through two horizontal wells at desert peak geothermal field
Energy, 2013Co-Authors: Yuchao ZengAbstract:In this work, heat production potential from hot dry rock by water circulating through two horizontal wells was numerically investigated based on the geological data of well DP23-1 under the enhanced geothermal system (EGS) project at Desert Peak geothermal field. The results indicate that the desirable electricity production power and energy efficiency can be obtained under suitable Reservoir Permeability, water production rate and injection temperature; meanwhile water flow impedance remains at a relative lower level. The sensitivity analysis indicates that the electricity production power mainly depends on the water production rate and the injection temperature; the water flow impedance mainly depends on the Reservoir Permeability, water production rate and injection temperature; the energy efficiency mainly depends on the Reservoir Permeability and the water production rate. The heat production performance will be improved when the Reservoir Permeability, the water production rate and the injection temperature are under reasonable conditions. However, this study is based on that the fractured Reservoir is equivalent to a homogeneous porous medium and there is no water loss in the Reservoir, so the practical energy output and efficiency of water circulating through two horizontal wells at Desert Peak geothermal field needs further study in the future.
