Abstract: To meet the need of composite reservoir performance analysis, a formation pressure distribution model is developed,which takes into consideration the effect of wellbore storage,skin factor and three kinds of outer boundary conditions—constant pressure outer boundary, closed outer boundary, infinite
boundary. The exact solution of the model in Laplace space is obtained by using Laplace transformation and Bessel function,and the application of the solution is discussed in detail. The method of well testing directly in the Laplace space is particularly described, and the specific procedures of its application are presented.

Key words: pressure distribution, mathematical model, laplace space, performance analysis