A new trap type: Fault-controlled fracture-vuggy trap

Sinopec Northwest Oilfield Company recently struck a billion ton-scale oil/gas discovery-the Shunbei oil and gas field-in the deep carbonates of Shuntuoguole low-uplift, Tarim Basin. A new trap type-fault-controlled fracture-vuggy trap-is found to be the major container for oil and gas in the field. Analyses show that the traps take the fracture-vuggy layers along strike-slip fault zone as reservoirs and the overlying mudstone and local tight carbonates as caprocks. The reservoirs are probably the result of a tectonic disruption of the Middle-Lower Ordovician carbonates under strike-slip faulting that induced the formation of a large number of fractures, vugs and caverns. Based on the style and fragmentation of strike-slip faults as well as the distribution of internal reservoirs in the field, this study classifies the traps into four sub-types: transpression type, translation type, transtension type and composite type. This new type of trap further enriches the theory of marine carbonate reservoirs for oil and gas and provides a scientific basis for future exploration and development in deep and ultra-deep carbonates. © 2022, OIL & GAS GEOLOGY Editorial Board. All right reserved.