六盘山盆地含油气系统与勘探方向

六盘山盆地经历了晚古生代类克拉通、中生代断陷和新生代再生前陆盆地三个阶段 ,至少经历了三期原型盆地充填 ,沉积盖层厚度大 ,发育三套海陆交互相和断陷湖盆较深湖相烃源岩 ,从而形成了三套含油气系统。这些含油气系统的发育、分布与构造运动息息相关。盆地北部兴仁堡凹陷后期改造以隆升为主 ,仅发育一套含油气系统 ,保存条件差 ;盆地中部海原凹陷晚期构造反转 ,以逆冲褶皱变形为主 ,后期改造较弱 ,发育多套含油气系统 ,勘探前景最好 ;盆地南部后期强烈挤压 ,形成多个逆冲块 ,含油气系统保存条件较差。

PETROLEUM SYSTEM AND EXPLORATION DIRECTION OF LIUPANSHAN BASIN

Liupanshan Basin has experienced three evolution stages : Late Paleozoic sub-cratonic ,Mesozoic faulting and Cenozoic rejuvenated foreland basins.Three periods sedimentary fillings have taken placed at least in the primary-type basin.Thus, there are very thick sedimentary covers and three sets of thick source rocks in the basin, which deposited in continental-oceanic interaction and relatively deep lake environments, forming three petroleum systems.The development and distribution of petroleum systems in the basin are closely related to tectonic movements.The late geological reform of Xinrenbao Depression in the north of the basin dominated by uplifting, only a set of petroleum system was developed here, and its preservative condition was very poor.The late tectonic inversion occurred in the Haiyuan Depression of central part in the basin mainly by thrusting.The folding and deformation was weak at the late geological reconstruction.Many sets of petroleum system with good petroleum exploration prospects were developed in the depression.Late intense compression occurred in the south of the basin, resulting in the development of many thrusted blocks, therefore, the preservative condition of these petroleum systems were relatively poor.