Numerical model of the two-phase medium weak compressible matrix and some geophysical applications

Since the Boussinesq approximation cannot be applicable to model accumulation of a liquid phase (fluid) within a matrix the numerical model of two-phase medium with weak compressible matrix has been developed. Because of weak compressibility there is a lot of computational difficulties to solve the system of equations by a numerical method with sufficient accuracy. Therefore it has been obtained an asymptotical solution including the Boussinesq approximation as zero-order one. The finite element technique combined with the modified project gradient method is applied to obtain numerical solution for zero-order and following approximations. This method has considerable advantages in accuracy, stability and speed of response in comparison with penalty method and modified Lagrange function method. There has been fulfilled numerical modeling of a fluid accumulation within compressible matrix affected by the upper boundary's relief and variation of the fluid flow's distribution on the lower boundary. The model shear strain field are shown to be different in comparison with Boussinesq approximation. Some features of shear strain distribution have been studied analytically. Several geophysical applications of these model results is presented.