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Qiusha Zheng - One of the best experts on this subject based on the ideXlab platform.
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A FRACTAL MODEL FOR GAS Apparent Permeability IN MICROFRACTURES OF TIGHT/SHALE RESERVOIRS
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal d...
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A FRACTAL MODEL FOR GAS Apparent Permeability IN MICROFRACTURES OF TIGHT/SHALE RESERVOIRS
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal dimension and the mean pressure.
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a fractal model for gas Apparent Permeability in microfractures of tight shale reservoirs
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal d...
Shifang Wang - One of the best experts on this subject based on the ideXlab platform.
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A FRACTAL MODEL FOR GAS Apparent Permeability IN MICROFRACTURES OF TIGHT/SHALE RESERVOIRS
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal d...
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A FRACTAL MODEL FOR GAS Apparent Permeability IN MICROFRACTURES OF TIGHT/SHALE RESERVOIRS
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal dimension and the mean pressure.
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a fractal model for gas Apparent Permeability in microfractures of tight shale reservoirs
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal d...
Xiuying Cao - One of the best experts on this subject based on the ideXlab platform.
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A FRACTAL MODEL FOR GAS Apparent Permeability IN MICROFRACTURES OF TIGHT/SHALE RESERVOIRS
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal d...
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A FRACTAL MODEL FOR GAS Apparent Permeability IN MICROFRACTURES OF TIGHT/SHALE RESERVOIRS
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal dimension and the mean pressure.
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a fractal model for gas Apparent Permeability in microfractures of tight shale reservoirs
Fractals, 2017Co-Authors: Shifang Wang, Xiuying Cao, Qiusha ZhengAbstract:The investigation of gas transport in microfractures of tight/shale reservoirs can provide potential applications in predicting shale gas production rates. In this paper, analytical expressions for flow rate and Apparent Permeability are derived based on the fractal theory and the superposition of convection and molecular diffusion transfer. The proposed model relates the flow rate and Apparent Permeability to the microstructural parameters of tight/shale reservoirs, gas properties, the ambient pressure as well as temperature. The model predictions from the present model are compared with existing experimental data sets and are found to be consistent with existing experimental measurements. The effects of microstructural parameters of tight/shale reservoirs on Apparent Permeability are also investigated. The results show that Apparent Permeability increases with temperature, the pore area fractal dimension, the porosity as well as the maximum microfracture width and decreases with the tortuosity fractal d...
Zhangxin Chen - One of the best experts on this subject based on the ideXlab platform.
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On the flow regime model for fast estimation of tight sandstone gas Apparent Permeability in high-pressure reservoirs
Energy Sources Part A: Recovery Utilization and Environmental Effects, 2019Co-Authors: Zhangxin Chen, Xiong Liu, Jie ZhanAbstract:A flow regime-based gas Apparent Permeability model in high-pressure tight sandstone reservoirs is established by bridging molecular kinetics, gas transport mechanisms, and Apparent Permeability. T...
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Image-based core-scale real gas Apparent Permeability from pore-scale experimental data in shale reservoirs
Fuel, 2019Co-Authors: Dongying Wang, Zhangxin Chen, Wenhui SongAbstract:Abstract This paper presents a new upscaling method to derive the core-scale Apparent gas Permeability from an improved pore-scale Permeability model and experimental data, with more rigorous incorporation of varying gas storage/transport mechanisms in nano/micro pores. First, in use of SEM images of a gas-rich shale field example in Sichuan Basin from our lab, pore network models of inorganic-matter (IOM) and organic-matter (OM) are characterized by using a digital-core technique. Next, an improved pore-scale real gas Apparent Permeability is modeled rigorously for both IOM/OM, respectively, with 1) bulk gas transport, gas adsorption, surface diffusion, pore-size confined phase behavior, and stress-dependent rock properties and 2) an additional reduction in inorganic pore sizes by water film adhered on pore surfaces. Core-scale Permeability is then derived by assembling the permeabilities of stochastically distributed IOM/OM patches with different pore network models properties using the Monte Carlo sampling method. The new core-scale Permeability model is validated by pulse-decay Permeability experiment. Moreover, the representative elementary volume (REV) size is determined by analyzing the relative standard deviation of Apparent gas Permeability in cases with different sample sizes. The contributions of different gas transport mechanisms are discussed, and the impacts of stress-dependence for several field examples (i.e., Sichuan, Pierre and Barnett Basins) and water film with varying relative humidity (RH) on core-scale Apparent Permeability are analyzed. This work provides an effective approach to determine the core-scale shale Permeability by directly using pore-scale experimental data, which is a common challenge in the unconventional resources.
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Estimation of Shale Apparent Permeability for Multimechanistic, Multicomponent Gas Production Using Rate Transient Analysis
Energy & Fuels, 2019Co-Authors: Erfan Mohagheghian, Hassan Hassanzadeh, Zhangxin ChenAbstract:Gas-producing shale and ultratight reservoirs are playing a key role in the energy industry and the global gas market. Compositional simulation of gas production from shale media in the presence of different mechanisms such as viscous flow, slip flow (Klinkenberg effect), Knudsen diffusion, sorption, pore radius variation, and real gas effect is a computational challenge. In this work, we present a model that takes into account all of the noted mechanisms of gas transport in shale media. It is shown that the compositional effect of gas in shale media can be lumped into a single component by introducing an Apparent gas Permeability, which can be estimated from the conventional rate transient analysis. The main contribution of this study is a workflow incorporating the relevant physics into a single term (Apparent Permeability) that will substitute the Darcy Permeability. This procedure reduces the simulation runtime substantially and will find applications in reservoir characterization and simulation of pr...
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A Novel Integrated Numerical Simulation Scheme for Transient Gas Flow in Shale Matrix
Day 1 Tue November 07 2017, 2017Co-Authors: Jie Zhan, Yifu Han, Allan Fogwill, Kongjie Wang, Hossein Hejazi, Zhangxin ChenAbstract:Abstract The gas flow in shale matrix is of great research interest for optimizing shale gas reservoir development. Due to a nano-scale pore radius, the gas flow in the shale matrix may fall in flow regimes which include viscous flow, slip flow and Knudsen diffusion. On top of that, the adsorbed and free gas is stored in nano-scale organic pores. The gas molecules are attached as a monolayer to pore walls to form a film of gas which is the thickness of the adsorbed layer. When a reservoir is depleted, the attached gas molecules will be released so that the radius of organic pores in which the free gas flows is changeable. Thus a sorption-dependent radius will be introduced to the Apparent Permeability which represents the flow regimes. Stress sensitivity will also be investigated via a two-way coupling geomechanics process. In this paper, we introduce a novel integrated numerical simulation scheme to quantify the above phenomena which is crucial for the shale gas reservoir development. Instead of Darcy's equation, we implement the sorption-dependent Apparent Permeability in the continuity equation to depict the gas flow (viscous flow, slip flow and Knudsen diffusion) in shale matrix. The methodology which was developed by Vasina et al. and validated through comparing with molecular simulation will be implemented to determine the thickness of an adsorbed layer at each time step. The Langmuir adsorption/desorption term is included in the continuity equation as an accumulation term. In addition, lab data for a Bakken reservoir which provides a relationship between a matrix pore radius reduction and the effective stress is integrated into the two-way coupling geomechanical process to simulate a stress-sensitive shale formation. This methodology examines the influence of each mechanism for the shale gas flow in the matrix. Overall, the sorption-dependent Apparent Permeability is smaller than the sorption-independent Apparent Permeability, which leads to the pressure maintenance for the sorption-dependent Apparent Permeability case. The sorption-dependent Apparent Permeability will lead to additional heterogeneity. The Apparent Permeability near a wellbore is bigger than the one far away from the wellbore, which causes the pressure transmit more easily around the production side. With the consideration of geomechanics, the Apparent Permeability is decreased due to the compaction of a nano-scale pore radius, which leads to the maintenance of reservoir pressure. Due to the difference of compaction magnitude for each grid block, geomechanics also creates additional heterogeneity for a nano-pore network in shale matrix, which we should pay more attention to. The sorption-dependent radius is incorporated into the Apparent Permeability model to depict the sorption-dependent Apparent Permeability of shale matrix. We provide a novel integrated methodology to quantify the crucial transient phenomena in the shale matrix, which includes flow regimes, gas adsorption/desorption and stress sensitivity.
Zhongying Han - One of the best experts on this subject based on the ideXlab platform.
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Fractal analysis of shale gas transport through micropores and microfractures
Fractals, 2021Co-Authors: Qi Gao, Songcai Han, Yuanfang Cheng, Yan Chuanliang, Zhongying HanAbstract:In order to commercially develop shale gas reservoirs, it is necessary to understand the gas transport mechanisms in shale matrix and how matrix Permeability evolves during reservoir depletion. In this work, improved Apparent Permeability models to describe gas transport through microstructures (i.e. micropores and microfractures) in organic matter (OM) and inorganic matter (iOM) of shale matrix are proposed. The models are able to consider the combined effects of poromechanics, non-Darcy flow, gas sorption and fractal dimension of microstructures on gas flow behavior. The obtained results indicate that microfracture aperture declines by a larger margin than micropore diameter when reservoir depletes. A greater microstructure size fractal dimension and maximum microstructure size lead to a larger Apparent Permeability, while a greater tortuosity fractal dimension leads to a smaller Apparent Permeability. In shale matrix, the Apparent Permeability of inorganic microstructures is much larger than that of organic microstructures. In OM or iOM, when micropores and microfractures have the same cross-section area, the Apparent Permeability of micropores is larger than that of microfractures. Furthermore, for microstructures in OM, the contribution of different flow regimes to total gas flow varies with pore pressure and microstructure size. For microstructures in iOM, the contribution of slip flow dominates the gas transport. The obtained results provide new insights for understanding gas transport behavior in shale reservoirs from a microscopic perspective.
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Apparent Permeability model for gas transport through micropores and microfractures in shale reservoirs
Fuel, 2021Co-Authors: Qi Gao, Songcai Han, Yuanfang Cheng, Chuanliang Yan, Zhongying HanAbstract:Abstract With the rapid development of horizontal well drilling and hydraulic fracturing techniques, shale gas has become a major source of energy in recent years. However, accurately characterizing the gas flow behaviour and predicting the Permeability evolution in shale matrix is still a challenge at present due to the existence of complex microstructures and volatile reservoir conditions. In this paper, an improved Apparent Permeability model is developed to analyze real gas transport through micropores and microfractures in shale formation. This new model is able to consider the combined effects of poromechanics, non-Darcy flow, gas sorption and fractal distribution of microstructures on gas Apparent Permeability. The results indicate that (1) microfracture aperture decreases more than micropore diameter during reservoir depletion; (2) with pore pressure decreasing, gas Apparent Permeability will continue to increase for smaller size microstructures while the Apparent Permeability will first decrease and then rebound for microstructures with larger size; (3) with pore pressure decreasing, the contribution of slip flow decreases while the significance of Knudsen diffusion increases, and the proportion of surface diffusion first increases and then decreases; (4) with microstructure size increasing, the contribution of slip flow at high pore pressure and the significance of Knudsen diffusion at low pore pressure increase, but the proportion of surface diffusion decreases; (5) gas Apparent Permeability of micropores is larger than that of microfractures when the cross section area is the same, and the larger aspect ratio leads to smaller microfractures Permeability.