Transient Flow In Naturally Fractured Reservoirs And Its Application To Devonian Gas Shales

Devonian shale gas reservoirs typically are characterized by a low storage, high flow-capacity natural fracture system fed by a high storage, low flow-capacity rock matrix. In this study analytical solutions are developed to analyze the basic fractured reservoir parameters that control well productivity. These parameters include fractured system porosity and permeability, matrix porosity and permeability, and matrix size. It is shown that the conventional well test method does not usually work for fractured Devonian shale gas reservoirs. For most cases, the semi-log plot of the drawdown then buildup data does not show 2 parallel straight lines with a vertical separation. Numerical solutions also are used to include the Klinkenberg effect and desorption in the shale matrix. 18 references.