Abstract: Determining pressure characteristics of fluid flow from a wellbore provides a method to obtain physical characteristics of a subterranean reservoir. An analytical solution of flow a flow model for an underground dual porosity reservoir is obtained for the transient flow regime of an unsteady flow exhibiting wellbore storage and skin effects. Using either the continuous solution or a set of type curves obtained from that continuous solution, a match is obtained with an experimental data set. The first time derivative of the dimensionless pressure solution to the flow model can also be used to more easily identify the dimensionless time at which the transient period ends. Using classical relationships between known values and information obtained from the type curves, the effective permeability, dimensionless fracture transfer coefficient, the skin factor, the dimensionless wellbore storage coefficient, and the dimensionless storativity ratio can be ascertained for the underground formation.