储集层沉积的两种极端模式——主动裂谷和被动裂谷

Two extreme modes of reservoir sedimentation: Active rift and passive rift

主动裂谷和被动裂谷是裂谷盆地的两种极端模式,这种极端性在储集层沉积中也得到了充分的体现。地幔热流上隆或板块俯冲引起的主动裂谷盆地,其发育顺序是火山活动在先,裂谷活动在后,储集层沉积为双模式单旋回;大陆岩石圈内拉张应力引起岩石圈强度减弱而形成的被动裂谷盆地,其发育顺序是裂谷活动在先,火山活动在后,储集层沉积为双模式多旋回。储集层的岩石学结构和储集物性与裂谷盆地的这两种极端模式也有很好的对应关系,即断陷期发育物性差的局部性储集层,拗陷期发育物性好的区域性储集层,被动裂谷盆地储集层物性好于主动裂谷盆地。

Active rift and passive rift are the two extreme modes of rift basin. These extreme modes are embodied in the sedimentation of reservoirs. Active rift basins originated from the apophysis of mantle heat flow or the plate subduction have the development sequence of volcanic activity followed by rift activity. The sedimentation of reservoir rocks is bimodal and monocyclic. Passive rift basins originated from the weakening of lithospheric intensity which is caused by extensional stress. The development sequence is rift activity followed by volcanic activity. The sedimentation of reservoir rocks is bimodal and multi-cyclic. The petrologic structure and physical properties of reservoirs also correspond very well with the two modes, that is, local reservoirs of poor properties are developed in the fault depression stage, regional reservoirs of good properties are developed in the depression stage, and the reservoir properties in passive rift basins are better than those in active rift basins.