Paleozoic Oil And Gas Preservation Conditions In The Eastern Chongqing

The Western Hubei-Eastern Sichuan Area is located at the junction belt between the Eastern Sichuan folded Belt in the Sichuan Basin and Xianexi folded belt , belong to eastern extended part, which is similar to the Eastern-Sichuan Structure in many aspects. For example, they share a structural unit, resulting in the same sedimentary history and the same generation-reservoir-seal assembly as each other. In addition, The Western Hubei-Eastern Sichuan Area has the same structural history and structural style, similar gas reservoir types and preserving conditions as those of the Eastern-Sichuan Structure. Commercial hydrocarbon reservoirs have been discovered in the Upper and Middle Paleozoic in the area. The festern Hubei-Eastern Sichuan area is considered as a st'rategic area for oil & gas exploration of marine strata over the South China. In the area, the Lower Paleozoic is also a new prospective play that should be actively explored, due to its beneficial hydrocarbon-generating conditions.The Lower Paleozoic oil & gas exploration practices within and adjacent to the Well Li-1 in the study area reveal that the preservative conditions are the key factors for petroleum reservoir generation, because the Lower Paleozoic has earlier hydrocarbon-generating times and had experienced reformations and destruction by multi-periodic tectonic movements. This paper attempts to give an evaluation and study of hydrocarbon preserving units, which focuses on tectonic evolutions and time-space evolutions of hydrocarbon preserving conditions, on the basis of systematically collecting and using data from the Well Li-1 and the neighboring area.The study results on hydrocarbon preserving conditions have suggest ed that influenced by latter tectonic movements, especially by the Yanshan~Himalayan tectonic movement, obviously different hydrocarbon preserving conditions occur between the eastern and the western parts bounded by the Qiyue Mountain. The whole Lower Paleozoic hydrocarbon enclosing and preserving conditions for the Shizhu Synclinorium-Fangdoushan antici inorium to the west of Qiyueshan Mountain have the advantage over those of the Qiyueshan antici inorium-Lichuan Synclinorium to the east of Qiyue Mountain. The former is a continuing preserving unit, beneficial to hydrocarbon preservation, which is the target area for the Lower Paleozoic oil & gas exploration.