中国边缘海盆地构造演化与油气分布富集规律

Characteristics of Tectonic Evolution and Distribution and Enrichment Patterns of Oil and Gas in the Chinese Marginal Basin

中国边缘海盆地处在欧亚、印度—澳大利亚及太平洋三大板块相互作用之新生代最活跃区域,其中,南部边缘海盆地尚受南海裂解扩张作用等多种因素的深刻影响,形成了具有断拗双层结构不同类型伸展型或伸展、走滑、挤压复合型盆地,沉积充填了古近纪断陷裂谷早期中深湖相地层及其烃源岩、古近纪断陷晚期煤系地层及烃源岩、新近纪拗陷期海相地层及其烃源岩,为油气形成奠定了雄厚的物质基础。受区域地质背景影响,边缘海盆地地壳性质及厚度从陆缘区到深海洋盆区具有逐渐递变的特点;盆地沉降沉积中心亦逐渐向深海洋盆迁移,导致其大地热流及地热场向洋盆区逐渐升高增强,加之与晚期新构造运动和烃源供给系统时空上的相互耦合配置,最终控制了边缘海盆地油气分布富集规律。

The Chinese marginal basin is located at the most active Cenozoic era,which is formed by the interaction of Eurasia, India-Australia and the Pacific plates,and its southern marginal basin is still subjected to the impact of the South China Sea cracking and expansion and many other factors,so the rift-depression double-layer structure basins have formed,which have different types,such as extensional or composite strike-slip-extrusion type. The sedimentation has filled in the basin,which is mid-deep lake face strata and hydrocarbon source rocks in the early phase of the Paleogene rift Valley,coal-bearing strata and hydrocarbon source rocks in the late phase of the Paleogene rift,and marine strata and hydrocarbon source rocks in the Neogene depression,which has laid a foundation for oil and gas formation. Due to the impact of the regional geological setting, the characteristics and thickness of the marginal basin crust has gradually graded features from the continental margin area to the deep ocean basin area. The basin subsidence deposition center has gradually migrated to the deep ocean basin,which results in the terrestrial heat flow and geothermal field increasing gradually to the ocean basin,coupled with the space-time mutual coupling configuration between advanced new tectonic movement and source supply system,which ultimately controls and restricts the law of oil and gas distribution and enrichment in marginal basin.