白云凹陷恩平组南部物源研究及其油气地质意义

恩平组是珠江口盆地白云凹陷已经获得勘探证实的主要烃源层系。对其物源的清晰认识是潜力烃源和有利储层发育研究的重要基础。基于大量的三维地震解释和有限的钻井资料分析，提出白云凹陷恩平组时期不仅有来自北部盆外物源的输入，同时存在来自南部隆起的物源贡献。已钻井岩石学特征、古地貌分析、地震剖面特征和碎屑锆石年代学特征表明，白云凹陷西南部恩平组具有砂地比超过80%、粒度较粗、发育NE向大规模高角度“S”型前积地震相、具有物源通道的古地貌以及碎屑锆石以中生代岩浆锆石为主的特征，这与凹陷北部盆外具有NW向较平缓的“叠瓦状”前积地震相和较老的前寒武纪—古生代的碎屑锆石年龄的特征截然不同。综合分析认为，恩平组时期白云凹陷的南部隆起物源为白云凹陷西南部提供了充足的陆源物质供给，对白云西南部的优质陆源海相烃源岩的发育有重要作用；同时云开低凸起恩平组砂体埋深浅，粒度粗，是重要的潜在优质储层，具有重要的勘探意义。

PROVENANCE OF ENPING FORMATION IN THE SOUTHERN BAIYUN SAG,PEARL RIVER MOUTH BASIN AND ITS IMPLICATIONS FOR PETROLEUM GEOLOGY

Exploration has proved that the Enping Formation is the major hydrocarbon source rock in the Baiyun Sag, Pearl River Mouth Basin. A clear picture of its provenance is critical for petroleum geological study of this area. 3D seismic interpretation and drilling data indicate that the sediments of Enping Formation sourced not only from the northern provenance outside the basin, but also from the Southern Uplift inside the basin. The petrographical, paleo-geomorphological, seismic data and clastic zircon age from drilling wells suggest that the Enping Formation is characterized by high sandstone/formation ratio, which is over 80%, coarser grains, large-scale, high-angle, "S"-shaped and NE prograding seismic facies, palaeo-geomorphology of channels, and Mesozoic magmatic zircon age. They are completely different from the northern source outside the basin, which has relatively gentle imbricated NW prograding seismic facies, and Precambrian-Paleozoic zircon. Final analysis shows that the delta from the Southern Uplift provides sufficient terrestrial material to the southwest of the Baiyun sag at the stage of the Enping Formation, and plays an important role in the development of high-quality marine source rocks. Meanwhile, the coarse and shallow Enping Formation sandstone in the Southern Uplift is an important potential reservoir and has important exploration significance.