A test well interpretation model consisting of matrix, fractures and vugs is presented in which the permeability of vugs decreases exponentially with pressure drop. A mathematical model which takes into account the effect of wellbore storage and skin factor is calculated in a fully-implicit finite-difference scheme. It is shown that the dimensionless permeability modulus causes a increase of pressure and its derivative. The interporosity-flow factor determines the time of the interporosity flow. The storativity-ratio influences the width and depth of the "concave" in the pressure derivative. The effect of the outer-boundary differs from that of a normal triple medium. The skin factor affects the whole pressure and the "heave" in the pressure derivative curve, while the dimensionless permeability modulus mainly affects the later pressure and pressure derivative.