Numerical Simulation of Fracture Width Influencing Law on Reservoir Permeability after Fracturing

Based on the fluid-solid coupling theory in porous media, a finite element simulation model for dynamic fracture creation is established and the finite element simulation program is developed, and then relevant finite element simulation is conducted on the permeability distribution under the simultaneous influence of fracture creation and pressure-released production. Research results demonstrate that the permeability distribution law after fracturing is similar for fractures with different widths, and the permeability distribution shapes in ellipse. When the maximal fracture width is greater than or equal to 6mm, the influence region on the permeability increases apparently with the increment of fracture width, so does the influence in the vicinity of the wellbore. The fracture creation and pressure-released production alternately dominates the alteration of permeability in different regions. Dynamic fracture creation plays a more important role in permeability alteration within the region less than 5m away from the wellbore axis. The larger for the fracture width, the more sensitive for the permeability alteration gradient is observed in the region in the vicinity of the wellbore. In the region 20m away from the wellbore axis, the pressure-released production affect more apparently since dynamic fracture creation has a negligible effect in the region. Key words:Fluid-solid coupling; Permeability; Fracture; Wellbore; Simulation