下扬子陆域海相中—古生界烃源岩有机质丰度特征及其岩相古地理

ABUNDANCE OF ORGANIC MATTERS IN MESOZOIC-PALEOZOIC MARINE SOURCE ROCKS OF INLAND AREA OF THE LOWER YANGTZE AND ITS BEARING ON LITHOFACIES PALEOGEOGRAPHY

通过开展陆地野外地质调查及资料收集发现,下扬子陆域海相中—古生界共发育4套主要烃源岩,从烃源岩有机质丰度角度分析,这4套烃源岩都是较好的烃源岩,具有很好的油气远景。结合烃源岩产出的岩相古地理背景,发现泥质烃源岩主要产出于早古生代深水陆棚—盆地相(下寒武统幕府山组和下志留统高家边组)和晚古生代海陆交互相(上二叠统龙潭组),而碳酸盐岩烃源岩则主要产出于碳酸盐岩台地相(下二叠统栖霞组),尤以局限台地相为优。研究沉积相带平面展布特征可以发现,烃源岩有利沉积相带明显具有向南黄海延伸的趋势,从而证明南黄海盆地海相中—古生界具有较好的油气潜力。

Geological survey and research data reveal that there are four sets of marine source rocks in the Mesozoic-Paleozoic of the Lower Yangtze Region.From the perspective of the abundance of organic matters,the four sets of hydrocarbons source rocks are all good enough for hydrocarbon generation.The lithofacies paleogeographic background indicates that the early Paleozoic argillaceous source rocks were mainly deposited in a deep water shelf basinal environment（the Lower Cambrian Mufushan Formation and the Lower Silurian Gaojiabian Formation）,and the late Paleozoic carbonate source rocks deposited in a paralic environment（the upper Permian Longtan Formation）,while the carbonate platform facies is deposited on a restricted platform（lower Permian Qixia Formation）.The spatial distribution of sedimentary facies suggests that the favorable source rocks obviously occur in a tendency to extend to the south Yellow Sea.It means that the marine Mesozoic-Paleozoic in the South Yellow Sea Basin is favorable for hydrocarbon generation and accumulation.