Production Performance of Perforation Clusters during Multistage Fracturing in Shale Gas Reservoirs

Gas production from each perforation cluster has an obvious difference along with the horizontal wellbore in shale gas reservoirs. Some special perforation clusters evenly do not produce any gas, which means that those perforation clusters are not fractured. In shale gas reservoirs, only when the shale gas section was fractured with equal volumes of fracturing fluids, gas can be produced evenly. In this study, a stress theory around the perforation tunnel considering the stress around the wellbore and an induced stress by leaking of the fluid and the tunnel is presented. The results show that (1) fractures will quickly be created at two of the three perforation clusters and then the fracture of the cluster initiates. (2) The rate through each cluster is different, and the fracture volume created will have a big difference. (3) The fracture distribution between three perforation clusters are different, thus shale gas production also will be different. The theory and the method presented in this paper, can be used for different reservoirs besides shale gas reservoirs, thus it can be applied and referred widely.