SUMMARY： Realizing the potential of geothermal energy as a cheap, green, sustainable resource to provide for the planet＇s future energy demands that a key geophysical problem be solved first： how to develop and mai...SUMMARY： Realizing the potential of geothermal energy as a cheap, green, sustainable resource to provide for the planet＇s future energy demands that a key geophysical problem be solved first： how to develop and maintain a network of multiple fluid flow pathways for the time required to deplete the heat within a given region. We present the key components for micro-scale particle-based numerical modeling of hydraulic fracture, and fluid and heat flow in geothermal reservoirs. They are based on the latest developments of ESyS-Particle--the coupling of the lattice sofid model （LSM） to simulate the nonlinear dynamics of complex solids with the lattice Boltzmann method （LBM） applied to the nonlinear dynamics of coupled fluid and heat flow in the complex solid-fluid system. The coupled LSM/LBM can be used to simulate development of fracture systems in discontinuous media, elastic stress release, fluid injection and the consequent slip at joint surfaces, and hydraulic fractur- ing; heat exchange between hot rocks and water within flow pathways created through hydraulic fracturing; and fluid flow through complex, narrow, compact and gouge- or powder-f＇flled fracture and joint systems. We demonstrate the coupled LSM/LBM to simulate the fundamental processes listed above, which are all components for the generation and sustainability of the hot-fractured rock geothermal energy fracture systems required to exploit this new green-energy resource.展开更多
Modern geodynamics is based on the study of a large set of models,with the variation of many parameters,whose analysis in the future will require Machine Learning to be analyzed.We introduce here for the first time ho...Modern geodynamics is based on the study of a large set of models,with the variation of many parameters,whose analysis in the future will require Machine Learning to be analyzed.We introduce here for the first time how a formulation of the Lattice Boltzmann Method capable of modeling plate tectonics,with the introduction of plastic non-linear rheology,is able to reproduce the breaking of the upper boundary layer of the convecting mantle in plates.Numerical simulation of the earth’s mantle and lithospheric plates is a challenging task for traditional methods of numerical solution to partial differential equations(PDE’s)due to the need to model sharp and large viscosity contrasts,temperature dependent viscosity and highly nonlinear rheologies.Nonlinear rheologies such as plastic or dislocation creep are important in giving mantle convection a past history.We present a thermal Lattice Boltzmann Method(LBM)as an alternative to PDE-based solutions for simulating time-dependent mantle dynamics,and demonstrate that the LBM is capable of modeling an extremely nonlinear plastic rheology.This nonlinear rheology leads to the emergence plate tectonic like behavior and history from a two layer viscosity model.These results demonstrate that the LBM offers a means to study the effect of highly nonlinear rheologies on earth and exoplanet dynamics and evolution.展开更多
In this paper,dynamic similarity conditions are derived for discrete element simulations by non-dimensionalising the governing equations.These conditions must be satisfied so that the numerical model is a good represe...In this paper,dynamic similarity conditions are derived for discrete element simulations by non-dimensionalising the governing equations.These conditions must be satisfied so that the numerical model is a good representation of the physical phenomenon.For a pure mechanical system,if three independent ratios of the corresponding quantities between the two models are set,then the ratios of other quantities must be chosen according to the similarity principles.The scalability of linear and non-linear contact laws is also investigated.Numerical tests of 3D uni-axial compression are carried out to verify the theoretical results.Another example is presented to show how to calibrate the model according to laboratory data and similarity conditions.However,it is impossible to reduce computer time by scaling up or down certain parameters and continue to uphold the similarity conditions.The results in this paper provide guidelines to assist discrete element modelers in setting up the model parameters in a physically meaningful way.展开更多
文摘SUMMARY： Realizing the potential of geothermal energy as a cheap, green, sustainable resource to provide for the planet＇s future energy demands that a key geophysical problem be solved first： how to develop and maintain a network of multiple fluid flow pathways for the time required to deplete the heat within a given region. We present the key components for micro-scale particle-based numerical modeling of hydraulic fracture, and fluid and heat flow in geothermal reservoirs. They are based on the latest developments of ESyS-Particle--the coupling of the lattice sofid model （LSM） to simulate the nonlinear dynamics of complex solids with the lattice Boltzmann method （LBM） applied to the nonlinear dynamics of coupled fluid and heat flow in the complex solid-fluid system. The coupled LSM/LBM can be used to simulate development of fracture systems in discontinuous media, elastic stress release, fluid injection and the consequent slip at joint surfaces, and hydraulic fractur- ing; heat exchange between hot rocks and water within flow pathways created through hydraulic fracturing; and fluid flow through complex, narrow, compact and gouge- or powder-f＇flled fracture and joint systems. We demonstrate the coupled LSM/LBM to simulate the fundamental processes listed above, which are all components for the generation and sustainability of the hot-fractured rock geothermal energy fracture systems required to exploit this new green-energy resource.
基金supported by the College of Petroleum Engineeing and Geosciences(CPG)at King Fahd University of Petroleum and Minerals,Saudi Arabia.This research was in part funded by the US DoE[Grant DE-SC0019759]the National Science Foundation,USA[Grant EAR-1918126]the NASA Emerging World program,USA[Grant 20-EW20_2-0026].
文摘Modern geodynamics is based on the study of a large set of models,with the variation of many parameters,whose analysis in the future will require Machine Learning to be analyzed.We introduce here for the first time how a formulation of the Lattice Boltzmann Method capable of modeling plate tectonics,with the introduction of plastic non-linear rheology,is able to reproduce the breaking of the upper boundary layer of the convecting mantle in plates.Numerical simulation of the earth’s mantle and lithospheric plates is a challenging task for traditional methods of numerical solution to partial differential equations(PDE’s)due to the need to model sharp and large viscosity contrasts,temperature dependent viscosity and highly nonlinear rheologies.Nonlinear rheologies such as plastic or dislocation creep are important in giving mantle convection a past history.We present a thermal Lattice Boltzmann Method(LBM)as an alternative to PDE-based solutions for simulating time-dependent mantle dynamics,and demonstrate that the LBM is capable of modeling an extremely nonlinear plastic rheology.This nonlinear rheology leads to the emergence plate tectonic like behavior and history from a two layer viscosity model.These results demonstrate that the LBM offers a means to study the effect of highly nonlinear rheologies on earth and exoplanet dynamics and evolution.
文摘In this paper,dynamic similarity conditions are derived for discrete element simulations by non-dimensionalising the governing equations.These conditions must be satisfied so that the numerical model is a good representation of the physical phenomenon.For a pure mechanical system,if three independent ratios of the corresponding quantities between the two models are set,then the ratios of other quantities must be chosen according to the similarity principles.The scalability of linear and non-linear contact laws is also investigated.Numerical tests of 3D uni-axial compression are carried out to verify the theoretical results.Another example is presented to show how to calibrate the model according to laboratory data and similarity conditions.However,it is impossible to reduce computer time by scaling up or down certain parameters and continue to uphold the similarity conditions.The results in this paper provide guidelines to assist discrete element modelers in setting up the model parameters in a physically meaningful way.
