Characteristics of fault-karst carbonate reservoirs in the Shunbei No.1 well block, Tarim basin

With the deepening of exploration practice for ultra deep carbonate reservoirs in Tarim basin, a new type of karst reservoirs has been found in the peripheral slope area of the Tahe river. The Shunbei No.1well area is the main production area of the Sinopec Shunbei oilfield, which is a typical fault-karst reservoir. The area has undergone 4 stages of development, a quasi syngenetic karst process on the top surface of Yijianfang formation, bedding strata of the Lianglitage formation and the dissolution of the fractured reservoir, buried karst in the Silurian Santamu formation and the late Permian hydrothermal karst transformation of the late Hercynian. Among them, the control of the 80-120 m emptying leakage below the top surface of Yijianfang formation is the bedding fracture controlled reservoir karst period of the Lianglitage formation. At the same time, it is considered that the necessary conditions for the development of dissolving body reservoirs in the Shunbei No.1 well area is the large-scale strike-slip pull-apart fault in the development region, where the dissection reflectors in the pull-apart section extend over large distances in plane and downward to large depths, marking the high quality and high yield reservoirs; while those in the thrust section show a plywood shape with narrow transverse extension, representing a secondary reservoir space.