Abstract: Aimed at the polluted zone produced around a well in the course of drilling, completing and producing and the heterogeneous conditions of triple-medium carbonate reservoirs, a well test interpretation model for triple-medium composite reservoir with consideration of skin effect and wellbore storage effect is developed. Through Laplace transformation, the Laplace space analytic solution has been obtained, and converted into real space solution by means of the numerical inversion of Stehfest. The pressure and the pressure derivative bilogarithmic type curves have been drawn up. From the physical percolation mechanism, the curve shape characteristics and the flow phase are analyzed and divided, obtaining the effects of inner-and outer-zone permeability ratio, inner-zone radius, interporosity flow coefficient and storativity ratio on the pressure behavior of such a reservoir. The results indicate that when the value of the permeability of inner zone is less than that of outer zone, the pressure derivative curves of these two zones will go down. On the contrary, when the value of the permeability of inner zone is bigger than that of outer zone, the pressure derivative curves of them will go up. It is concluded that the radius of inner zone determines the time of pressure transmitting to the boundary of the outer zone; the interporosity flow coefficient determines the coming time of crossflow; the storativity ratio affects the degree and the lasting time of crossflow. These results can be used for study of percolation of tripe-medium composite reservoirs and for analyses of pressure behavior and well test.

Key words: triple-medium, composite reservoir, mathematic model, well test