松辽盆地的反转构造作用及其对油气成藏的影响

Reverse structures and their impacts on hydrocarbon accumulation in Songliao basin

松辽盆地的反转构造以宽缓的褶曲和长垣背斜为主 ,属小变形量的反转构造。反转构造可划分为 3期 ,即晚白垩世嫩江组沉积末期、明水组沉积末期和新生代晚期。其中 ,嫩江组沉积末期的反转构造最强烈 ,对松辽盆地油气成藏的影响最大 ,主要体现在 :(1)反转构造为油气聚集提供了圈闭 ;(2 )反转构造作用促进了油气再次运移 ;(3)反转构造作用使地层拱张 ,产生了许多裂缝 ,改善了储集性能。

Reverse structures in Songliao basin are mainly wide and gentle folds and placanticline with small deformation.The reverse structures have been formed in three differant stages:at the end of deposition of Nenjiang Formation in Late Cretaceous,at the end of deposition of Mingshui Formation and Late Cenozoic.The strongest reverse structural action that occurred at the end of deposition of Nenjiang Formation would have the largest effect on hydrocarbon accumulation in Songliao basin,including (a) reverse structures provide traps for hydrocarbon accumulation; (b) reverse structural actions promote remigration of hydrocarbons; and (c) reverse structures result in many fractures and thus improve the poroperm characteristics of reservoir rocks.