| Different from conventional reservoirs,shale fracture network structure is complex,and its self-propped fracture conductivity is a key factor affecting productivity.At present,the research on the conductivity of self-supported fractures is mainly experimental,but the experimental research is influenced by many factors such as limited testing conditions and high sample preparation difficulty.Therefore,the deformation model of rough dislocation fracture under stress and the fluid flow model in rough fracture morphology are completely established in this paper,so as to calculate the simulated conductivity of shale fracture.The fracture width of the rough dislocation fractures established by the combination shows a single peak similar to normal distribution and a very strong fractal feature.Shale stress-strain characteristic model and the generalized hooke’s law is used to calculate elastic stage,and by defining stress mutation coefficient of elastic stage to brittle ductile phase change process,and on this basis,through the discrete micro displacement calculation,discrete micro yuan yuan contact stress deformation calculation to form stress under the action of rough displacement fracture deformation model.A three-dimensional lattice Boltzmann flow model was established to simulate the rough fracture morphology and calculate the simulated conductivity.By conducting conductivity of 6 groups of rock samplesThe simulation results are verified by evaluation experiments.The results show that the established numerical model has good simulation accuracy.The numerical model of shale self-supported fracture conductivity established in this paper can effectively predict and analyze the variation rule of shale self-supported fracture conductivity.The research results can provide basic parameters for shale fracturing design,productivity evaluation and production system optimization,and have reference significance for the flow research in other rough fractures.. |
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