Abstract: Based on the flow behavior of the high energy gas in oil well，the mass and momentum conservation equations of high energy gas flow in fracture are established and the boundary conditions are defined.Besides，the distribution relationship between gas loading rate at the inlet of the fracture and the deflagration gas pressure are qualitatively analyzed by the semi-analytical method.Considering the dynamic response of crack tip，the fracture initiation and propagation under the function of high energy gas are analyzed based on the dynamic energy release rate analyzing method of the fracture mechanics.The fracture velocity and length can be obtained by iterative solution of dynamic energy release rate equation in every time step when loading rate is given，as well as the conditions of fracture initiation and arrest.In the case study，the results further show that dynamic response of high energy gas on fracture greatly influences the ultimate fracture propagation.Compared with quasi-static results，the dynamic process can provide a higher crack arrest pressure，earlier arrest of fracture and a much shorter fracture length.
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Key words: multi-pusle, high energy gas, dynamic response, fracture morphology, modelling