渤海湾盆地侵入岩-外变质带油气藏类型及成藏条件

侵入岩－外变质带油藏是渤海湾盆地不容忽视的隐蔽油藏类型。在大量的侵入岩体中，只有侵入岩厚度大于15m，具有有效裂缝带发育、直接嵌置或紧邻成熟烃源岩的（超）浅成侵入岩，以及分布在同生断层附近的、潜山裂缝发育带中的脉岩具备有利成藏条件。侵入岩裂缝储层的形成可能来自构造断裂作用、晚期岩浆底辟或刺穿，或者构造差异升降；不同的裂缝发育机理决定了不同的油藏分布特征。在侵入岩相邻的碎屑岩地层中可能伴生岩浆底辟（或刺穿），或侵入岩侧向遮挡成因的地层油气藏以及变质热液成因的CO2气藏。这些侵入岩－外变质带油藏主要分布在渤海湾盆地陆上探区的砂三段、海域（包括滩海）的沙一段成熟烃源岩中；具有中生界深断裂背景的第三系控洼断层是寻找脉岩油藏的有利地区。

Reservoir types and forming conditions in intrusion rock-exomorphic zone of Bohai Gulf basin

In Bohai Gulf basin, reservoirs in intmsion rock - exomorphic zone are not negligible and belong to subtle reservoirs. For intrusion, only those (super) hypabyssal intrusion rocks with thickness over 15 m, having effective fracture zone, and inserted in or immediately adjacent to mature source rock, and those dikes near contemporaneous fault and within buried hill fracture zone have favorable reservoir forming conditions. Fracture reservoirs of intrusion rock may result from structural faulting, latter magma diapir or piercement, or differential structural uplift and subsidence; different fracture development mechanism resulted in different reservoir distribution. In clastic formation with adjacent intrusion rocks, there might be associated magma diapir (or piercement) , or stratigraphic reservoir formed by lateral barrier of intrusion rock and CO2 gas reservoir of metamorphic hydrothermal origin. These reservoirs in intrusion rock - exomorphic zone of Bohai Gulf basin mainly distributed in mature source rocks in s3 formation onshore and sl formation offshore (including tidal zone) ; Tertiary sag controlling fault exhibiting Mesozoic deep faulting feature is favorable area for finding dike reservoirs.