Tectonic evolution and deformation characteristics analysis of Yining sag

Through comprehensive research of drilling,geological outcrop,seismic and geology,as well as equilibrium profile analysis of Yining sag in Yili basin,there were four tectonic evolution stages in all since Mesozoic period,namely the weak extrusion fault depression basin formation in IndoChinese epoch,foreland compressional basin formation and development in early-mid Yanshanian epoch,micro imbalance integral lifting transformation in late Yanshanian epoch,and thrust nappe strongly heterogeneity development of lacustrine basin in late Himalayan epoch.Tectonic evolution in Indo-Chinese and Yanshanian epoch was the key period for hydrocarbon generation and migration of Permian Tamqisayi formation and Triassic Baijiantan formation.Among the four tectonic deformation zones,the Huocheng Quluhai weak deformation belt,as well as the deformation zone in Chaxian Y2 well are relatively intact,with good trap development,good hydrocarbon migration and accumulation conditions,and it is the main direction of hydrocarbon exploration for next step.