Northwest Sichuan Region Of Triassic Leikoupo In The Reservoir

The paper guided by the theory of carbonate sedimentology, reservoir geology, karstology and the advanced improvement in the world, this thesis, whose main studied objects are outcrop sections, drilling and logging information, it also adopts multi-subjects, multi-techniques synthesis methods and advanced analysis techniques to in-depth and detailed study the strata, rocks, sediment, diagenesis and reservoirs of the Leikoupo Formation of Middle Triassic in northwestern Sichuan Province. The type and characteristics of sedimentary facies and diagenesis are described in detail, and it analyzes its effects on reservoirs, by this way it formulizes the dominated control factors of reservoirs evolution and developed, establishes the modes of important reservoir, predicts the profitable region of good reservoirs.Study suggests that the main reservoir rocks are composed of the dolarenites and grain conglutinate dolomites. The corrosion pore, formed on the secondary cause, is predominant in reservoir space, whereas the dissolve cavities and primary pores are less. Fracture plays the main role in connecting the pores. On the whole, the reservoirs belong to the pore type of moderate porosity and moderate-lower permeability, and the fracture-pore type of moderate porosity and high permeability. It is karst reservoir on basis of secondary dissolve pore that experiences the karst corrosion result of hypergene and burial period, which lies in the high energy bank of the subtidal zone on the limited epicontinental sea. The reservoir characteristics are the final products of sedimentation, diagenesis and the other factors in the geological history as long as two thousand millions.Longitudinally, the reservoirs, with thickness of 50-100m, mainly distribute in the middle part of member 3 of the Leikoupo Formation, and develop below 150—200m from the top of airslake interface. Horizontally, they are developing very well along Zhongba-Shuangyushi, which are favorable for exploration, but developing not so well along Shejianhe—Wangcang and Guanyintan—Tianjingshan and the other places developing less.