The Experts below are selected from a list of 18468 Experts worldwide ranked by ideXlab platform
Feixue Yulong - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation on heat extraction performance of a multilateral well enhanced geothermal system with a discrete Fracture network
Fuel, 2019Co-Authors: Xianzhi Song, Jiacheng Li, Gaosheng Wang, Rui Zheng, Feixue YulongAbstract:Abstract Our previous study (Song et al., 2018) proposed a novel enhanced geothermal system (EGS) with multilateral wells and demonstrated that it had greater heat extraction performance than double-well EGS. However, to further enhance the heat extraction performance of multilateral-well EGS, an efficient and complex Fracture network needs to be created to connect injection and production wells. In order to know which kind of discrete Fracture network (DFN) should be created to improve the heat extraction performance of multilateral-well EGS, it is extremely important to investigate effects of DFN on multilateral-well EGS performance. Therefore, in this study, we develop a thermal-hydraulic-mechanical (THM) coupling model to investigate the heat extraction performances of various DFNs. The model is verified by an analytical solution. Based on the model, effects of rock mechanical behavior on Fracture Permeability evolution and EGS heat extraction performance are studied. The sensitivity analysis of reservoir properties and injection temperature on THM coupling process are conducted. Influences of Fracture parameters, including number of Fractures, Fracture length and orientation, on multilateral-well EGS performance are investigated. The results indicate that the rock contraction could increase Fracture Permeability and promote the preferential flow and thermal breakthrough. The injection temperature and reservoir properties have significant effects on the rock deformation and heat extraction performance of multilateral-well EGS. The DFN with complex and longer Fractures and without too many direct connections between lateral wells and Fractures is beneficial for multilateral-well EGS performance. The results of this study provide significant suggestions for the fracturing operation of multilateral-well EGS.
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numerical investigation on heat extraction performance of a multilateral well enhanced geothermal system with a discrete Fracture network
Fuel, 2019Co-Authors: Yu Shi, Gaosheng Wang, Xianzhi Song, Rui Zheng, Feixue YulongAbstract:Abstract Our previous study (Song et al., 2018) proposed a novel enhanced geothermal system (EGS) with multilateral wells and demonstrated that it had greater heat extraction performance than double-well EGS. However, to further enhance the heat extraction performance of multilateral-well EGS, an efficient and complex Fracture network needs to be created to connect injection and production wells. In order to know which kind of discrete Fracture network (DFN) should be created to improve the heat extraction performance of multilateral-well EGS, it is extremely important to investigate effects of DFN on multilateral-well EGS performance. Therefore, in this study, we develop a thermal-hydraulic-mechanical (THM) coupling model to investigate the heat extraction performances of various DFNs. The model is verified by an analytical solution. Based on the model, effects of rock mechanical behavior on Fracture Permeability evolution and EGS heat extraction performance are studied. The sensitivity analysis of reservoir properties and injection temperature on THM coupling process are conducted. Influences of Fracture parameters, including number of Fractures, Fracture length and orientation, on multilateral-well EGS performance are investigated. The results indicate that the rock contraction could increase Fracture Permeability and promote the preferential flow and thermal breakthrough. The injection temperature and reservoir properties have significant effects on the rock deformation and heat extraction performance of multilateral-well EGS. The DFN with complex and longer Fractures and without too many direct connections between lateral wells and Fractures is beneficial for multilateral-well EGS performance. The results of this study provide significant suggestions for the fracturing operation of multilateral-well EGS.
Xianzhi Song - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation on heat extraction performance of a multilateral well enhanced geothermal system with a discrete Fracture network
Fuel, 2019Co-Authors: Xianzhi Song, Jiacheng Li, Gaosheng Wang, Rui Zheng, Feixue YulongAbstract:Abstract Our previous study (Song et al., 2018) proposed a novel enhanced geothermal system (EGS) with multilateral wells and demonstrated that it had greater heat extraction performance than double-well EGS. However, to further enhance the heat extraction performance of multilateral-well EGS, an efficient and complex Fracture network needs to be created to connect injection and production wells. In order to know which kind of discrete Fracture network (DFN) should be created to improve the heat extraction performance of multilateral-well EGS, it is extremely important to investigate effects of DFN on multilateral-well EGS performance. Therefore, in this study, we develop a thermal-hydraulic-mechanical (THM) coupling model to investigate the heat extraction performances of various DFNs. The model is verified by an analytical solution. Based on the model, effects of rock mechanical behavior on Fracture Permeability evolution and EGS heat extraction performance are studied. The sensitivity analysis of reservoir properties and injection temperature on THM coupling process are conducted. Influences of Fracture parameters, including number of Fractures, Fracture length and orientation, on multilateral-well EGS performance are investigated. The results indicate that the rock contraction could increase Fracture Permeability and promote the preferential flow and thermal breakthrough. The injection temperature and reservoir properties have significant effects on the rock deformation and heat extraction performance of multilateral-well EGS. The DFN with complex and longer Fractures and without too many direct connections between lateral wells and Fractures is beneficial for multilateral-well EGS performance. The results of this study provide significant suggestions for the fracturing operation of multilateral-well EGS.
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numerical investigation on heat extraction performance of a multilateral well enhanced geothermal system with a discrete Fracture network
Fuel, 2019Co-Authors: Yu Shi, Gaosheng Wang, Xianzhi Song, Rui Zheng, Feixue YulongAbstract:Abstract Our previous study (Song et al., 2018) proposed a novel enhanced geothermal system (EGS) with multilateral wells and demonstrated that it had greater heat extraction performance than double-well EGS. However, to further enhance the heat extraction performance of multilateral-well EGS, an efficient and complex Fracture network needs to be created to connect injection and production wells. In order to know which kind of discrete Fracture network (DFN) should be created to improve the heat extraction performance of multilateral-well EGS, it is extremely important to investigate effects of DFN on multilateral-well EGS performance. Therefore, in this study, we develop a thermal-hydraulic-mechanical (THM) coupling model to investigate the heat extraction performances of various DFNs. The model is verified by an analytical solution. Based on the model, effects of rock mechanical behavior on Fracture Permeability evolution and EGS heat extraction performance are studied. The sensitivity analysis of reservoir properties and injection temperature on THM coupling process are conducted. Influences of Fracture parameters, including number of Fractures, Fracture length and orientation, on multilateral-well EGS performance are investigated. The results indicate that the rock contraction could increase Fracture Permeability and promote the preferential flow and thermal breakthrough. The injection temperature and reservoir properties have significant effects on the rock deformation and heat extraction performance of multilateral-well EGS. The DFN with complex and longer Fractures and without too many direct connections between lateral wells and Fractures is beneficial for multilateral-well EGS performance. The results of this study provide significant suggestions for the fracturing operation of multilateral-well EGS.
William J Carey - One of the best experts on this subject based on the ideXlab platform.
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multiphysics lattice discrete particle modeling m ldpm for the simulation of shale Fracture Permeability
Rock Mechanics and Rock Engineering, 2018Co-Authors: Xinwei Zhou, William J Carey, L P Frash, Gianluca CusatisAbstract:A three-dimensional multiphysics lattice discrete particle model (M-LDPM) framework is formulated to investigate the Fracture Permeability behavior of shale. The framework features a dual lattice system mimicking the mesostructure of the material and simulates coupled mechanical and flow behavior. The mechanical lattice model simulates the granular internal structure of shale, and describes heterogeneous deformation by means of discrete compatibility and equilibrium equations. The network of flow lattice elements constitutes a dual graph of the mechanical lattice system. A discrete formulation of mass balance for the flow elements is presented to model fluid flow along cracks and intact materials. The overall computational framework is implemented with a mixed explicit–implicit integration scheme and a staggered coupling method that makes use of the dual lattice topology enabling the seamless two-way coupling of the mechanical and flow behaviors. The proposed model is used for the computational analysis of shale Fracture Permeability behavior by simulating triaxial direct shear tests on Marcellus shale specimens under various confining pressures. The simulated mechanical response is calibrated against the experimental data, and the predicted Permeability values are also compared with the experimental measurements. Furthermore, the paper presents the scaling analysis of both the mechanical response and Permeability measurements based on simulations performed on geometrically similar specimens with increasing size. The simulated stress strain curves show a significant size effect in the post-peak due to the presence of localized Fractures. The scaling analysis of Permeability measurements enables prediction of Permeability for large specimens by extrapolating the numerical results of small ones.
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multiphysics lattice discrete particle modeling m ldpm for the simulation of shale Fracture Permeability
arXiv: Geophysics, 2018Co-Authors: Xinwei Zhou, William J Carey, L P Frash, Gianluca CusatisAbstract:A three-dimensional Multiphysics Lattice Discrete Particle Model (M-LDPM) framework is formulated to investigate the Fracture Permeability behavior of shale. The framework features a dual lattice system mimicking the mesostructure of the material and simulates coupled mechanical and flow behavior. The mechanical lattice model simulates the granular internal structure of shale and describes heterogeneous deformation by means of discrete compatibility and equilibrium equations. The network of flow lattice elements constitutes a dual graph of the mechanical lattice system. A discrete formulation of mass balance for the flow elements is formulated to model fluid flow along cracks. The overall computational framework is implemented with a mixed explicit-implicit integration scheme and a staggered coupling method that makes use of the dual lattice topology enabling the seamless two-way coupling of the mechanical and flow behaviors. The proposed model is used for the computational analysis of shale Fracture Permeability behavior by simulating triaxial direct shear tests on Marcellus shale specimens under various confining pressures. The simulated mechanical response is calibrated against the experimental data, and the predicted Permeability values are also compared with the experimental measurements. Furthermore, the paper presents the scaling analysis of both the mechanical response and Permeability measurements based on simulations performed on geometrically similar specimens with increasing size. The simulated stress-strain curves show a significant size effect in the post-peak due to the presence of localized Fractures. The scaling analysis of Permeability measurements enables prediction of Permeability for large specimens by extrapolating the numerical results of small ones.
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Fracture Permeability behavior of shale
Journal of Unconventional Oil and Gas Resources, 2015Co-Authors: William J Carey, Zhou Lei, Esteban Rougier, Hiroko Mori, Hari S ViswanathanAbstract:Abstract The Fracture-Permeability behavior of Utica shale, an important play for shale gas and oil, was investigated using a triaxial coreflood device and X-ray tomography in combination with finite-discrete element modeling (FDEM). Fractures were generated in both compression and in a direct-shear configuration that allowed Permeability to be measured across the faces of cylindrical core. Shale with bedding planes perpendicular to direct-shear loading developed complex Fracture networks and peak Permeability of 30 mD that fell to 5 mD under hydrostatic conditions. Shale with bedding planes parallel to shear loading developed simple Fractures with peak Permeability as high as 900 mD. In addition to the large anisotropy in Fracture Permeability, the amount of deformation required to initiate Fractures was greater for perpendicular layering (about 1% versus 0.4%), and in both cases activation of existing Fractures are more likely sources of Permeability in shale gas plays or damaged caprock in CO2 sequestration because of the significant deformation required to form new Fracture networks. FDEM numerical simulations were able to replicate the main features of the fracturing processes while showing the importance of fluid penetration into Fractures as well as layering in determining Fracture patterns.
Alec M. Marshall - One of the best experts on this subject based on the ideXlab platform.
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Elastic–Brittle–Plastic Behaviour of Shale Reservoirs and Its Implications on Fracture Permeability Variation: An Analytical Approach
Rock Mechanics and Rock Engineering, 2018Co-Authors: Mohsen S. Masoudian, Mir Amid Hashemi, Ali Tasalloti, Alec M. MarshallAbstract:Shale gas has recently gained significant attention as one of the most important unconventional gas resources. Shales are fine-grained rocks formed from the compaction of silt- and clay-sized particles and are characterised by their fissured texture and very low Permeability. Gas exists in an adsorbed state on the surface of the organic content of the rock and is freely available within the primary and secondary porosity. Geomechanical studies have indicated that, depending on the clay content of the rock, shales can exhibit a brittle failure mechanism. Brittle failure leads to the reduced strength of the plastic zone around a wellbore, which can potentially result in wellbore instability problems. Desorption of gas during production can cause shrinkage of the organic content of the rock. This becomes more important when considering the use of shales for CO_2 sequestration purposes, where CO_2 adsorption-induced swelling can play an important role. These phenomena lead to changes in the stress state within the rock mass, which then influence the Permeability of the reservoir. Thus, rigorous simulation of material failure within coupled hydro-mechanical analyses is needed to achieve a more systematic and accurate representation of the wellbore. Despite numerous modelling efforts related to Permeability, an adequate representation of the geomechanical behaviour of shale and its impact on Permeability and gas production has not been achieved. In order to achieve this aim, novel coupled poro-elastoplastic analytical solutions are developed in this paper which take into account the sorption-induced swelling and the brittle failure mechanism. These models employ linear elasticity and a Mohr–Coulomb failure criterion in a plane-strain condition with boundary conditions corresponding to both open-hole and cased-hole completions. The post-failure brittle behaviour of the rock is defined using residual strength parameters and a non-associated flow rule. Swelling and shrinkage are considered to be elastic and are defined using a Langmuir-like curve, which is directly related to the reservoir pressure. The models are used to evaluate the stress distribution and the induced change in Permeability within a reservoir. Results show that development of a plastic zone near the wellbore can significantly impact Fracture Permeability and gas production. The capabilities and limitations of the models are discussed and potential future developments related to modelling of Permeability in brittle shales under elastoplastic deformations are identified.
Tsuneo Ishido - One of the best experts on this subject based on the ideXlab platform.
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pressure transient behavior during cold water injection into geothermal wells
Geothermics, 1998Co-Authors: Shinsuke Nakao, Tsuneo IshidoAbstract:During injection testing, the pressures in geothermal wells used for reinjection sometimes initially increase but then decline as injection continues. Injection tests carried out at the Yutsubo geothermal field in Kyushu, Japan, exhibit this peculiar behavior. During injection testing of Yutsubo well YT-2, the observed downhole pressures eventually began to decline despite sustained injection rates. We have carried out numerical simulation studies using a radial flow model to examine this behavior. Double porosity (MINC) models are adopted, in which the Fracture porosity increases as a result of both cooling and pressure build-up, and the Permeability is very sensitive to porosity changes. This extreme sensitivity of Fracture Permeability to porosity appears to be necessary to reproduce the late-time pressure decline, and suggests that Fractures were opened by injection-induced cooling near the well.
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pressure transient behavior during cold water injection
Proceedings Twenty-First Workshop on Geothermal Reservoir Engineering Stanford University Stanford CA January 22-24 1996, 1996Co-Authors: Shinsuke Nakao, Tsuneo IshidoAbstract:During injection testing, pressures in geothermal wells sometimes decline after an initial period of increase despite continued injection. The injection tests carried out at the Yutsubo geothermal field in Kyushu, Japan exhibit this peculiar behavior. During injection testing of Yatsubo well YT-2, observed downhole pressures eventually began to decline despite sustained injection rates. We have carried out numerical simulation studies using a radial flow model to examine this behavior. Double porosity ("MINC") models are adopted, in which the Fracture porosity increases due both to cooling and to pressure buildup, and the Permeability is very sensitive to porosity changes. This extreme sensitivity of Fracture Permeability to porosity appears to be necessary to reproduce the late-time pressure decline, and suggests that Fractures were opened by injection-induced cooling near the well.
