新构造运动对塔里木盆地油气的控制作用

Control Effect of Neotectonic Movement on Hydrocarbons in Tarim Basin

塔里木盆地周缘存在着强烈的新构造运动,主要表现为强烈的逆冲推覆构造,下更新统西域组(Q1x)在盆地周缘不同地区逆冲推覆在不同的地层之上或者被不同时代的老地层所覆盖,同时其也卷入了不同规模的褶皱之中。三维地震资料的精细解释显示塔里木台盆区志留系以上的地层因新构造运动而产生了区域性的构造反转,不同层位的地层顶面构造高点发生了向南迁移。新构造运动对塔里木盆地油气的控制作用表现为:在塔里木盆地的周缘形成了有利于晚期成藏的大型构造圈闭,并为晚期油气运移提供了成藏的强大动力;对早期形成的古油藏圈闭条件的改造和破坏,导致了古油藏内的油气发生重新运移,从而形成了具有复杂油水界面的现今正在充注的新油藏。

The neotectonic movement around Tarim basin assumes intense thrust nappe structure. The Xiyu formation of Lower Pleistocene （Q1x） in different areas around the basin thrusts into different strata or is covered by old strata in different ages and rolled into folds in different scales. 3D seismic interpretation indicates that regional tectonic inversion occurs in strata above Silurian system in Tarim platform area owing to neotectonic movement, leading to southward migration of top structural highs in different horizons. The neotectonic movement has two effects on controlling hydrocarbons in Tarim basin. One is that some large-scale structural traps favorable for late-stage hydrocarbon accumulation were formed around this basin and provided huge power for hydrocarbon migration in late stage. The other is the movement changed and reconstructed the trap conditions of ancient oil reservoirs shaped in early stage, resulting in the hydrocarbon remigration in them and consequently forming new oil reservoirs with complex oil-water contact and still being charged with fluid nowadays.