Characteristics and hydrocarbon accumulation controlling factors of Neogene Shawan Formation reservoir in Chepaizi uplift, Junggar Basin

The characteristics of the Neogene Shawan Formation reservoirs in Chepaizi uplift are summarized and analyzed according to their layers, sizes, oil qualities, physical property, origins, and types. Lithological, fault-lithological and fault nose traps are the major traps where Shawan Formation was developed. Reservoir characteristics and sizes vary in different reservoirs. The distribution of oil character is very complex. Based on an analysis of the typical reservoirs, the authors hold that long-term inherited paleouplift, effi-cient blanket-like sand body, fault sealing properties, difference of litholoies and physical properties, and multi-source and multistage accumulation together with storage condition constitute the main controlling factors for the hydrocarbon accumulation. On such a basis, it is pointed out that the blanket sand's lateral pinch zone is the favorable oil accumulation zone. Drilling reveals that the area possesses rich oil resources and shows good prospect for exploration.