Study On Paleostructure Restoration And Gas-controlling Action Of Carboniferous-Permian In The South Of The Qinshui Basin

By using geological,drilling,geophysical data and organic geochemistry analyses,the process of palaeostructure recovery experiences from Balanced section technique,denudation recovery technique and seismic data interpretation.The Carboniferous-Permian Formation's palaeostructure can be recovered by the point-plane comprehensive consideration,combined with a variety of recovery methods.By choosing the best method and the optimal data,the ancient fracture system and compaction correction should be consideredduring the process of palaeostructure recovery.The recovery result has a guiding significance to oil and gas exploration and evaluation of the south of Qinshui Basin area.The south of Qinshui Basin area experienced strong extruding deformation such as Yanshanian movements and middle Hercynian-Himalayan movements,Different uplift and extensional movement of the basin controls the migration of the erosion area and the evolution of the long depression.By comparing with different strata denudation calculating method and alladvantages and disadvantages,finally choose interval transit time method to restore the top surface of Permian formation,combined with other recovery methods,found the top Permian strata denudation thickness overall performance on the grounds of North South and east west trend to decrease,the erosion trend line is North East and denudation scope with the period of tectonic evolution by denudation center around to expand.On this basis,taking into account the formation of the compaction correction,the evolution history of the study area can be analysed by making the balanced section,and the use of petromod simulation,in order to select the best simulation results.Based on Calculating the top surface of the Taiyuan Formation?T₇?and the top surface of Shanxi Formation?T₅?in early Yanshanian,late Yanshanian and middle Himalayan ancient buried depth,the top surface of Taiyuan Formation?T₇?and the top surface of Shanxi Formation?T₅?in the corresponding period of ancient tectonic can be restored,with superposition of the corresponding period of pale-fracture system.The results show that the study area experience Yanshan early uplifted movement,the North fracture areas experience the most intensely.the buried depth of Shanxi Formation is commonly 610 to 3800m and the buried depth of Taiyuan Formation is commonly 670³900m;In late Yanshanian period,the buried depth of Shanxi Formation is commonly 540³500m,the buried depthofTaiyuanFormationiscommonly600³560m;Inmiddle Hercynian-Himalayan period,the buried depth of Shanxi Formation is commonly 400²400 m.the buried depth of Taiyuan Formation is commonly 500²500m.The denudation of the whole region has certain synchronization.Uplift area is mainly located in the surrounding area and the southern basin in the study area.