Reservoir-forming Conditions and Exploration Orientation of Southern Thrust Belt, Santanghu Basin

Southern Thrust Belt in Santanghu Basin is located at the south of Central Depression Belt. A southern thrusting nappe fault zone is between these two belts. In addition, the former is very close to Tiaohu and Malang hydrocarbon-generating sags. There are lots of reservoir-seal associations developed at Southern Thrust Belt. The thrusting nappe fault zone was generated by late Hercynian movement and late Yanshanian movement; furthermore, two structural zones of Shibandun and Heidun are developed at the lower wall of fault zone. At present, many reservoirs with multiple sequences, including Hedun P2l, Shibandun C2k, J2x in Xishan’ gou M4-T14 Block, were discovered and demonstrated to a complex hydrocarbon accumulation belt. Reservoir formation and distribution are controlled by structure, lithology, fracture and volcanic rock. In the next, the Permian fractured reservoirs in Southern Thrust Belt should be further studied; the exploration of both Palaeozoic volcanic and Mesozoic sandstone reservoirs will be strengthened; and the exploration strategy should be changed from one point that structural high is drilled in structural reservoirs to some points that channel is drilled in lithological reservoirs, fractured zone is drilled in fractured reservoirs and volcanic body is drilled in volcanic-rock reservoirs.