Reconstruction Of Burial History Of The Upper Triassic Xujiahe Formation In The Middle Of Sichuan Area And Discussion On Controlling Factors Of Gas-water Distribution In Key Structure

The upper Triassic is one of the important oil enrichment in Si chuan basin,it's abundant in petroleum deposits.But it's not yet studied the general tectonic evolution of the Triassic,and it's not realized really the inherited structural highs in the sedimentation ,and affected to know the Gas and Water Distributing Law in this area.and affected to know the Enrichment characteristics of oil and gas and the selection of roll exploration objects of Xujiahe Formation of the upper Triassic in this area.On the basis of reading a great amount of materials, the paper calculated and restored the burial history 120 wells at the Xujiahe formation and the overlying formation in the middle of Sichuan, combining with the gas-water relation analysis, sedimentation and tectonics of Xujiahe formation in the middle of Sichuan were restored systematically and key paleostructure evolution and gas-water contact was researched and the following conclusion were gained:(1) According to Algorithm analysis on paleoburial depth in different period, the regional paleostructure evolution in Xujiahe formation of the Middle Sichuan presents long-time succeeding developed from depression at west of Sichuan and Suinan-longnvsi uplift, at Tongjiang area of North of Sichuan depression was a slope during sedimentation of Xujiahe formation and Ziliujing formation , lasted for Shaximiao depression. It located in the high point of paleostructure in Suinan, Moxi, Longnvsi, Nanchong area, and it's the oil and gas advantageous accumulation zone.(2) Through burial history restoring on 21 wells of Nanchong structure, palaeostructure evolution in Xujiahe formation' of Nanchong structure in the upper Triassic shows traits of similarity and succeeding at Xujiahe formation.(3) By study on paleostructure, tectonics today and gas-water distribution of Nanchong structure it shows that the gas reservoir in Xujiahe formation was controlled by tectonic evolution and property of reservoir.(4) Through analysis of burial history restoring on Moxi structure,Moxi structure formed...