渤海湾盆地的复式油气聚集带——以辽河西部、廊固和东濮三个凹陷为例

渤海湾盆地早第三纪区域构造运动以块断差异运动为特征。在拉张应力场作用下,基础岩体持续经受拉裂、滑落和翘倾活动,形成箕状断陷。基础断块的构造格局是半地垒和半地堑相间。与基础断块构造格局相适应,早第三纪凹陷盆地也具隆凹相间的格局。不对称的箕状凹陷就是独立的盆地构造单元、沉积单元和生油单元。渤海湾盆地的复式油气聚集带指不同构造层、多个含油层系、多种类型油气藏在时间上的叠加和在空间上的复合。本文对此概括为四个方面进行论述:(1)基础层和盖层;(2)基础断裂和盖层断裂;(3)基础构造和盖层构造;(4)断裂构造岩相带。

MULTIPLE OIL-GAS ACCUMULATION ZONES IN BOHAI BAY BASIN

Block-faulting differential activity appears to be a feature of regional tectonic-structural movements of Bohai Bay Basin in Paleogene The basement bloks .beceme wedg-shaped downfaults through successive pulling-apart, down-sliping and tilting under tensile stress. The tacicnie regime of the basement block is "half horsts" alternating with "half grabens" , correspondingly, the basic setup of the Palsogen fault depression basin is juxtaposition of uplift and depression units. Asymmetrical wedge-shaped depressions are independent structural units of the basin, usually occurring as an independent sedimentary unit and an independent unit of oil generation. In Bohai Bay Basin, there exist multiple types of traps in several reservoir-systems of different tectonic layers, being supsrimposed one upon another horizontally and vertically and resulting in multiple oil-gas accumulation zones. This subject is discussed in four topics; (1) Basement layers and sedimentary covering strata; (2) Basement faults and contemporaneous faults; (3) Basement structures and sedimentary covering and gravity-structures; (4) Faulting-sturuc tral lithofacies zones