南黄海中-古生代海相残留盆地埋藏生烃史模拟及其意义

Modelling of burial and hydrocarbon-generation histories of Meso-Paleozoic marine residual basins in South Yellow Sea and its geologic significance

南黄海南部地区二叠系上统大隆组—龙潭组和三叠系下统青龙组的海相残留盆地形成于印支至燕山运动早期,为一系列的逆冲背斜断垒带组成,与苏北地区南京-安丰对冲带相接,经历克拉通形成、挤压冲断和裂陷走滑三个演化阶段。大隆组—龙潭组和青龙组是其主要的烃源岩。根据构造演化、地层结构的不同,可将南黄海地区划分为两种生烃模式:勿南沙隆起一次深埋藏一次生烃模式,潜山内幕油气藏是主要勘探对象;而在南部坳陷区则为两次深埋藏两次生烃模式,可形成海相和陆相多套含油气系统和油气藏,潜山油气藏、潜山内幕油气藏是其主要勘探对象。

Taking the Upper Permian Dalong-Longtan Formations and the Lower Triassic Qinglong Formation in the southern part of South Yellow Sea as examples, it is discusses exploration and appraisal methods of this remnant marine basin. According to analysis, the residual basin was formed during Indosinian and early Yanshanian. It was composed of a series of thrusted anticline-horst zones and was connected with the Nanjing-Anfeng ramp zone. It experienced three evolutionary stages, including craton formation, compressional thrusting and chasmic strike slipping, which resulted in two hydrocarbon generation modes, with Dalong-Longtan Formations and Qinglong Formation to be the source rocks, respectively. The former has been deeply buried and accompanied by hydrocarbon generation just for one time, just like those in Wunansha uplift, where the buried hill oil and gas reservoirs would be the main exploration targets. The latter has been deeply buried twice and each to be accompanied by hydrocarbon generation, just as those in the southern downwarping region, where several marine and continental petroleum systems and oil and gas accumulations might have been developed.