吐哈盆地台北凹陷洼陷区侏罗系断裂特征及控藏作用OA

Fault system is a key geological factor controlling hydrocarbon accumulation in Shengbei,Qiudong and Xiaocaohu sub-sags of Taibei Sag in Tuha Basin.However,the geometric characteristics,evolutionary process of these fault systems and their control on hydrocarbon accumulation are still unclear,significantly resericting hydro-carbon exploration in Jurassic Taipei Sag.Based on geological and geophysical data,development characteristics and evolution processes of faults in 3 sub-sag zones of Taibei Sag(Shengbei,Qiudong and Xiaocaohu sub-sags)are analyzed through fault structure analysis,fault sealing evaluation and structural fracture prediction techniques,ex-ploring the controlling effect of faults on Jurassic hydrocarbon accumulation.The results show that,Jurassic sub-sag zones in Taibei Sag mainly develop 2 types of fault systems including thrust and strike-slip,with deformation domi-nated by thrust faults and supplemented by strike-slip faults.Regional detachment layers in Xishanyao Formation and Badaowan Formation control the layered deformation of faults in sub-sag zones,with intense deformation above the detachment layers and weak deformation below.Jurassic faults can be divided into Yanshanian active faults,Hi-malayan active faults and long-term active faults.The faults mainly formed during middle Yanshanian period,devel-oped and were finalized during Himalayan period,exhibiting inherited development characteristics.Hydrocarbon accumulation is jointly controlled by fault-caprock configurations and structural fractures.The degree of fault dam-age to caprocks governs hydrocarbon migration and accumulation,while structural fractures significantly improve the pore structure and flow capacity of tight sandstone reservoirs.The research provides guiding significance for un-derstanding hydrocarbon accumulation and further exploration deployment in this area.