Inversion of Permeability in High Pressure Packer Test under Hydro-Mechanical Coupling of Dual Media
Hydraulic fracturing easily occurs in rock masses under high-pressure packer tests,involving dual water conduction via pores and cracks.This interaction between the seepage and stress fields results in spatial-temporal variations in rock mass permeability parameters.For accurate permeability parameter inversion during high-pressure packer tests,it is recommended to consider the change in permeability coefficient before and after fracture occur-rence under hydro-mechanical coupling of dual media.A hydro-mechanical coupling numerical model is employed to simulate high-pressure packer tests,and parameter inversion is conducted using on-site test data to calculate limestone permeability across different pressure stages.Key findings include:before hydraulic fracturing,as injec-tion pressure increases,permeability and pore water pressure sees distinct boundaries among different pressure sta-ges,with inverted permeability closely aligning with specified formula values.After hydraulic fracturing,rock mass permeability increases by about 2 times,accompanied by sharp declines in matrix pore medium permeability and flow rates.
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