Three-dimensional in-situ stress modeling of heterogeneous reservoirs with local faults

The Luzhou block in the Sichuan Basin has a smooth overall stratum, slight dip angle, and few fractures. Still, anticlines, folds, and faults are locally developed, and the distribution of in-situ stress is complicated. Since the in-situ stress field significantly influences on-site fracturing design, it is imperative to grasp the regional in-situ stress field's distribution law. The finite element method was employed to model the in-situ stress of the shale gas reservoir in the Luzhou block. The locally embedded fault network method was used to construct the primary faults in the formation. The information of in situ stresses in whole the geometric model and main shale gas reservoir layers, and on the fault surfaces can be acquired. The in-situ stress information of this area and a single local area was predicted, including stress gradients and stress disturbance range. The changes in the in-situ stress field are limited to the vicinity of the stress disturbance zone, and the changes in the formation stress far away from the fault are not apparent. The vertical stress of the Longmaxi formation is greatly influenced by the stress disturbance zone near the fault.