Abstract: There exist non Darcy's flow and starting pressure in a low permeability reservoir according to analyses of experiments and effect of low velocity non Darcy's flow. This paper proposed mathematic model for well test analysis of perfectly describing non Darcy's flow with starting pressure gradient and its solution, and offered type curve of non Darcy's flow under inner and outer boundaries. The type curve is not only helpful to well test interpretation, but also can be used as a powerful tool to correctly understand and study special law of low permeability reservoirs.

Key words: low permeability reservoir, non Darcy 's flow, mathematic model, curve, application