酒泉盆地南缘老君庙构造带应力场数值模拟

老君庙构造带处于酒泉盆地南缘新生代前陆冲断带上,纵向上,叠置于早白垩世断陷盆地的南部隆起和石大凹陷之上。利用构造应力场数值模拟计算,分别对酒泉盆地南缘山前冲断带的老君庙构造带新生代平面断裂系统及老君庙构造带西段北东向地质剖面进行应力场分析。通过与油气分布区域的对比,得出了以下结论:应力场数值模拟X方向位移场显示构造带西侧的断层具有左行走滑性质,构造带中部以逆冲为主,东部断层位移具有右行走滑的性质;Y方向位移场显示断层位移具有左行走滑性质。老君庙构造带上高应力区中所圈闭的低应力区是油气聚集最有利的区域,应该把这些应力圈闭区域作为油气勘探的重点,如庙西背斜、老君庙推覆体中盘、下盘以及老君庙背斜翼部等低应力圈闭区。

The Stress Numerical Simulation of Laojunmiao Structural Belt of South Margin, Jiuquan Basin

Laojunmiao structural belt is located in Cenozoic foreland thrust belt of south margin,Jiuquan basin,which is superposed over the south uplift and Shida depression of Early Cretaceous faulted basin.The author adopts the structural stress numerical simulation analysis in this article,and makes the stress analysis separately based on the Cenozoic planar fault system and NE geological profile of Laojunmiao structural belt.Through contrast with the oil distribution area,we can draw the conclusion as the following: X-displacement field shows that fault displacement in the west of structural belt is characteristic of left-lateral slip component;The middle of the structural belt mainly consists of thrust faults;In the east,the fault displacement has the component of right-lateral strike slip;for the Y-displacement,it is characteristic of left-lateral slip.Low stress areas which are surrounded by high stress in the Laojunmiao structural belt are the most advantageous oil accumulation regions.We should take these stress traps as an emphasis in the process of oil exploration,such as low stress traps in Miaoxi anticline,the middle clamping piece,the bottom part of Laojunmiao thrust belt and the wing of Laojunmiao anticline.