伊宁凹陷构造演化与变形特点分析

Tectonic evolution and deformation characteristics analysis of Yining sag

通过伊犁盆地伊宁凹陷钻井、地质露头、地震、地质综合研究,平衡剖面分析等研究认为,自中生代以来所划分的印支期弱挤压断坳盆地形成、燕山早中期的类前陆挤压盆地形成与发展、燕山晚期的微不均衡整体升降改造、喜山期强烈逆冲推覆不均一湖盆发展等四个构造演化阶段中,印支-燕山期的构造演化是区内二叠系塔姆其萨依组和三叠系白碱滩组烃源岩的油气生成、运聚的最关键时期,所划分的四个构造变形区中霍城-曲鲁海弱变形带和察县-Y2井中等变形带是研究区内地层保存较为完整、圈闭较为发育、油气运聚条件最为有利的区带,是下步油气勘探的主要方向。

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.