南堡凹陷优质烃源岩的新发现

南堡凹陷是渤海湾盆地油气富集程度极高的凹陷之一。该凹陷Es3^4的有效烃源岩厚250m左右，优质烃源岩厚100m左右，其镜质体反射率在0．8％以上，是南堡凹陷最重要的烃源岩。优质烃源岩有机碳含量高达5％以上，发育的富含有机质黏土层和细粒方解石纹层结构是湖水季节性分层作用和藻类勃发导致的结果，无定形体和藻质体是其有机质的重要来源。生物标志化合物组成特点表明，烃源岩有机质主要来源于水生生物，形成于淡水还原环境，陆源物质输入较少。资源评价表明，Es3^4烃源岩的生油量约为60亿t，主要为优质烃源岩生成，占南堡凹陷总生油量的40％；形成的资源量在7．5亿t左右。图10表2参48

High-quality source rocks in Nanpu Sag

The Nanpu Sag is one of the hydrocarbon-rich depressions in the Bohai Bay Basin. The 4th section of the 3rd member of the Shahejie Formation (Es34) is the most important source rock with 250m effective thickness, about 100m high-quality source rock and above 0.8% vitrinite reflectivity. In the high-quality source rock with TOC exceeding 5% develop clay layers rich in organic material coming from amorphous and algal solids and fine-grained calcite lamination, which are the result of seasonal stratification of lake and algal blooming. The biomarker components indicate that the organic material of the source rock mainly comes from hydro-biont, which existed in a fresh water and deoxidation environment, and to a less extent from land organic matter. The resource evaluation indicates that the oil-generating amount of Es34 is about 6×109t which accounts for 40% of the total in the Nanpu Sag and the resource amount is about 7.5×108t.