Abstract: The sensitivity coefficients to the porosity are derived from the initial boundary value problems for the fluid equations in porous media by the Green's Reciprocity Principle. The sensitivity coefficients of wellbore pressure to the porosity are obtained by the Peaceman's equation and calculated with a numerical method for the 3D transient anisotropic fluid equation in porous media and verified with the direct method. The computed results are in agreement with those obtained with the direct method.

Key words: porosity, sensitivity coefficients, numerical calculation, Green's Reciprocity Principie, geophysics inversion