南黄海古生代盆地原型演变与烃源岩发育特征

Paleozoic basin prototype evolution and source rock development in the South Yellow Sea

朱伟林 陈春峰 张伯成 万延周 付晓伟 张银国

ZHU Weilin CHEN Chunfeng ZHANG Bocheng WAN Yanzhou FU Xiaowei ZHANG Yinguo

同济大学 海洋地质国家重点实验室, 上海 200092 中海石油(中国)有限公司 上海分公司, 上海 200335 中国地质调查局 青岛海洋地质研究所, 山东 青岛 266071

State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China Shanghai Branch of CNOOC China Ltd., Shanghai 200335, China Qingdao Institute of Marine Geology, China Geological Survey, Qingdao, Shandong 266071, China

钻井及露头证实下扬子陆区发育下寒武统幕府山组、上奥陶统五峰组—下志留统高家边组、二叠系3套烃源岩。盆地发育时期的动力学环境决定该时期的盆地原型，盆地原型影响盆内岩相及烃源岩展布。幕府山组沉积时期，南黄海盆地表现为张裂背景下的被动陆缘克拉通盆地，盆地相及深水陆棚相呈环带状围绕古隆起或台地发育，为烃源岩发育优势相带，推测南黄海盆地中部隆起及北部幕府山组烃源岩发育较好；五峰组—高家边组沉积时期，南黄海盆地表现为挤压背景下的前陆盆地，盆地相、斜坡相、深水陆棚相由西北向东南依次呈条带状分布，盆地相、深水陆棚相为烃源岩发育优势相带，预测五峰组—高家边组烃源岩主要在南黄海地区中北部发育且有一定厚度；上二叠统龙潭组沉积时期，南黄海盆地表现为挤压背景下的活动大陆边缘坳陷型盆地，在该盆地中各沉积相带呈环带状分布，三角洲相、潮坪相、沼泽相为烃源岩发育优势相带，发育龙潭组品质中等—好的烃源岩；预测龙潭组烃源岩在南黄海盆地中部发育，是南黄海盆地古生界的次要烃源岩。

Drill samples and outcrops confirmed that three sets of source rocks developed in the Lower Yangtze Block area, namely, the Lower Cambrian Mufushan Formation, the Upper Ordovician Wufeng Formation-the Lower Silurian Gaojiabian Formation, and the Permian. This tectonic environment determined the evolution of the basin, which then affected the distribution of lithofacies and source rocks. During the deposition of the Lower Cambrian Mufushan Formation, the South Yellow Sea Basin was a passive continental cratonic margin basin undergoing regional extension. The basin facies and deep-water shelf facies developed around the paleo-uplift or platform, which were the dominant facies for the development of source rocks. It was predicted that this set of source rock developed well in the Middle Uplift and the northern part of the South Yellow Sea Basin. During the depositing of Wufeng and Gaojiabian formations, the South Yellow Sea Basin was a compressional foreland basin. The basin facies, slope facies and deep-water shelf facies were distributed in strips from the northwest to the southeast of Lower Yangtze area. The basin facies and deep-water shelf facies were dominant facies in which source rocks developed well. It was predicted that the source rocks of Wufeng-Gaojiabian formations were distributed mainly in the middle and north part of the South Yellow Sea Basin. During the deposition of the Upper Permian Longtan Formation, the South Yellow Sea Basin experienced active continental margin convergence. The sedimentary facies in the basin were scattered in ring belts. Delta and tidal flat facies were dominant with moderate to good quality source rocks. It was predicted that the source rocks of the Longtan Formation developed in the middle part of the South Yellow Sea Basin, which was the secondary source rock of Paleozoic in the South Yellow Sea Basin.

中国—东盟海上合作基金项目 12120100500017001

https://doi.org/10.11781/sysydz202005728