徐家围子断陷深层结构形成与演化的探讨

徐家围子断陷是松辽盆地北部深层最重要的含气断陷。本文根据最新地震和钻井资料综合研究成果,结合前人研究认识,探讨了徐家围子断陷的形成与演化,认为徐家围子断陷在区域构造位置上处于东北地区松辽盆地的北部,处于松辽盆地区域莫霍面隆起的西斜坡上,特定的位置决定了其形成演化的各个阶段受东北地区区域板块构造运动的控制,与松辽盆地的形成与演化具有一定的关系。徐家围子断陷形成与演化可以划分为5个阶段,是太平洋构造域板块间的相互作用和深部热力作用发育演化的结果,这种过程造就了现今南北分块、东西分带、凹隆相间、构造复杂和沉积岩与火山岩并存的地质结构。徐家围子断陷深层现今构造格局受控于近NW向的徐中断裂、近SN向的徐西断裂、近NW向的徐东断裂带和四组近NE向的断裂。本次研究,对以往无法解释的很多地质现象给予了很好的解释,得出了一些崭新的认识,也从宏观上为寻找天然气资源给予了有力指导。

Study on the formation and evolution of deep structure of Xujiaweizi fault depression

Xujiaweizi fault depression is the most important gas-bearing fault depression in the deep of Songliao basin. On the basis of the latest seismic and drilling data research achievements, this article research the formation and evolution of Xujiaweizi fault depression again, combining with the recognition of predecessors. Xujiaweizi fault depression is situated in the north of Songliao basin, and on the western slope of Moho uplift in regional tectonic position, the specific position of Xujiaweizi fault depression has decided that its every stage of formation and evolution is controlled by the tectonic movement of northern regional plate. It also has certain relationship with formation and evolution of Songliao basin. We can divide the formation and evolution of Xujiaweizi fault depression into five stages, which is the result of development and formation course of interaction of Pacific tectonic plates and action of deep thermal. This periodic cycles of processing has created the present geological structure with the characteristic, which is different segmentation from south to north, various zones from east to west, alternating with protruding and sunken belt,structurally complex and sedimentary coexist with volcanic rocks. Xujiaweizi fault depression deep zones are controlled by four sets of faults, such as nearly north-west Xuzhong fault, nearly south-north Xuxi fault, nearly north-west Xudong fault belt and four groups of nearly north-east fault. This research offers well interpretations for a lot of the past geological phenomena we can't explain, and obtains some new recognition, which gives effective guidance to find natural gas resource from macro-level at the same time.