Abstract: Based on a mathematical model of non-Darcy unsteady seepage flows in low-permeability porous media with moving boundary conditions,a differential equation of propagation velocity for moving boundary was deduced.It indicates that propagation velocity of a moving boundary is proportional to the second derivative of formation pressure with respect to radial distance on the moving boundary.And with Lagrange three-point interpolation formula,finite difference scheme of governing equation near a moving boundary was obtained.Exact position of a moving boundary is able to be tracked.Numerical results show that the front tracking method describes propagation behaviors of moving boundary of non.Darcy unsteady seepage flows in low-permeability porous media well.

Key words: low-permeability porous media, front tracking method, non-Darcy seepage flow, threshold pressure gradient, finite difference method