Abstract: This paper developed a nonlinear flow numerical model with starting pressure gradient of de- formation medium zone, in light of such properties of Tuoshi low permeability reservoir as developed natural fractures, non-constant payzone permeability occurred during oilfield development, in-situ fluid flow that is not in accordance with Darcy's Law,and starting from deformation medium percolation theory. Also, it presented equations for well output and pressure under the condition of stable nonlinear flow for deformation medium, and made comparisons of well output under the conditions of Darcy's flow for elastic medium and deformation medium, as well as non-Darcy's flow for elastic medium and nonlinear flow of deformation medium. Study showed that well output for deformation medium nonlinear flow is the lowest at the same producing pressure differential.

Key words: low permeability, reservoir, percolation, nonlinear, elastic medium, deformation