南黄海盆地中部隆起中—古生界海相油气多期成藏——来自CSDP-2井的勘探启示

大陆架科学钻探CSDP-2井不仅完成了南黄海盆地中部隆起的首次钻探，也创造了陆架区2 843.18 m的全取心深钻记录。在CSDP-2井钻遇的三叠系青龙组（T₁q），二叠系大隆组（P₃d）、龙潭组（P_2-3l）、孤峰组（P₂g）、栖霞组（P₁q）和志留系坟头组（S₁f）等多层段岩心中探获了多类型、多级别的油气显示，且二叠系3个油砂样品表明该区曾经历过大规模的油气运聚过程。地球化学分析、油源对比结果表明：1^#油砂和2^#油砂层段均表现出"近源成藏"的特征，其中大隆组1^#油砂中的原油与大隆组、龙潭组上段泥岩的亲缘关系明显，龙潭组2^#油砂中的原油与龙潭组下段、孤峰组和栖霞组烃源岩具有更好的亲缘关系；3^#油砂中的原油成熟度明显偏低，推测其可能来自两侧坳陷区的白垩系、古近系烃源岩；盆地模拟和含烃流体包裹体测温相互印证，明确了CSDP-2井揭露的四套烃源岩与三套储集层之间存在着"接力式"生烃和"波浪式"充注的多期成藏特征，同时得益于三套盖层的良好封盖，彰显了研究区较为广阔的海相油气勘探前景。

Multi-Stage Accumulation of the Meso-Paleozoic Marine Hydrocarbon in Central Uplift of South Yellow Sea:Exploration Significance of Borehole CSDP-2

Supported by the Continental Shelf Drilling Program(CSDP), borehole CSDP-2 is not only the first drilling in the central uplift of the South Yellow Sea basin, but also a full-drilling record with a depth of 2 843.18 m. The multi-types and multi-levels oil and gas have been detected in the cores of the Triassic Qinglong Formation, Permian Dalong, Longtan, Gufeng and Qixia Formations, and Silurian Fentou Formation. Three Permian oil sand samples obtained from borehole CSDP-2 indicate a large-scale migration and accumulation of oil and gas in this study area. The geochemical analysis and oil-source rock correlation reveal the near-source hydrocarbon accumulation in the oil sands of 1# and 2#. Among them, the crude oil in the 1# oil sand of the Dalong Formation has obvious genetic relationship with the source rocks of the Dalong Formation and Upper Longtan Formation, the crude oil in the 2# oil sand of the Longtan Formation is closely related to the source rocks of the Lower Longtan, Gufeng, and Qixia Formations;While the crude oil in the 3# oil sand is in obviously low maturity, which may be derived from the Cretaceous and Paleogene source rocks in the depressions on both sides of the central uplift. The mutual corroboration of basin modelling and temperature measurement of hydrocarbon-bearing inclusions shows the multi-stage hydrocarbon accumulation characteristics with relay hydrocarbon generation and wavy hydrocarbon charging between the four sets of source rocks and three sets of reservoirs in borehole CSDP-2, which is benefited from the good sealing of the three sets of caprocks. It proves a relatively broad exploration prospect for marine oil and gas in the South Yellow Sea basin.