Abstract:

Rift basins are defined as some sedimentary basins that have undergone rifting movement during a particular evolutional period in geologic history. The deep strata in rift basin are the main oilbearing and gasbearing intervals with burial depth more than 3500 m in China and over 4000 m overseas. Reservoirs in deep strata dominantly developed in the Mesozoic and Cenozoic rift basins in Eastern China, and  huge reservoirs in global rift basins mainly occurred in the Cretaceous and the Upper Paleozoic. The types of oil reservoir in deep horizons are various, including porosity type, fracture type, dissolved cavityfracture type, porosityfracture type, etc. Migration direction of hydrocarbon in deep horizons was predominantly vertical. The traps were often related to lithology and faults, and thus the structurallithologic composite traps formed. In addition, movements of halite also played an important role in the formation of traps, mainly forming composite type of traps.

Key words: rift basin, deep buried strata, geological characteristics, petroleum enrichment