Abstract: Upon the revised Horner equation by Seetharam and Jenes. a new method for the early stage interpretation of pressure build-up curve was developed. The results of well test modeling and field application indicated that the results of processing afterflow data and caculating formation parameters by means of this new method are gene-ally identical with the ones of estimating middle stage data of build-up pressure using rype-curve match and Horner's method. Furthermore, this new method is simpler than the type-curve match.

Key words: Well test interpretation, Afterflow, Pressure build-up analysis