A Study on Reservoir Inversion Methods for Shelf-Edge Reef and Bank-Type Fractured and Dissolved Reservoirs: A Case Study of the Yingxia Section and Penglaiba Formation in the D Area

The oil and gas accumulation patterns in the D study area are clear, primarily controlled by strike-slip faults and beach bodies for both reservoir and trap formation. The carbonate reservoirs in this area are characterized by two main types: First, karst reservoirs controlled by faults, where the surrounding fracture-cavity reservoirs exhibit strong heterogeneity; second, beach-controlled beach-phase reservoirs. By integrating the finely delineated fault breccia zone data volume with the spatial outline data of high-quality reservoirs and the original low-frequency model through scaling and fusion, a new heterogeneous low-frequency model is formed. This model can effectively reflect the heterogeneity of fracture-cavity reservoirs and significantly improves the accuracy of reservoir prediction. The dual-phase control inversion method, applied to the Yijianfang-Yingshan section in the D study area, has shown good results with predictions matching the actual drilling outcomes. However, the dual-phase control inversion results fail to represent the shelf-edge reef and beach bodies. For the Yingshan section and the Penglaiba Formation in the study area, sensitive attributes that can accurately reflect the boundaries of reef and beach bodies were selected to establish a reef and beach phase reservoir model. On the basis of the dual-phase control inversion, the shelf-edge reef and beach body reservoir models were added as constraints to further conduct beach phase reservoir constraints. Compared with the dual-phase control inversion, which can only display fault breccia zones and bead strings, the triple-phase control inversion further characterizes the beach bodies and effectively supports the work in the study area.