北黄海西部海底沥青的地球化学特征

GEOCHEMICAL BEHAVIOR OF SUBMARINE BITUMEN IN THE WEST OF THE NORTH YELLOW SEA BASIN

为了预测北黄海西部海域的含油气远景,利用沉积物矿物鉴定、红外光谱和有机气相色谱对150个站位542个表层样和柱状样中的沥青进行分析测试,结果表明,北黄海西部海域存在相当数量的沥青组分,主要分布在粒度较细的研究区西部,主要走向NNE,其次为NW。不同深度沥青颗粒的OEP值显示,北黄海西部海底存在轻微油污染。结合前人对北黄海烃源岩和前中生界基底的研究成果以及沥青高含量分布区的位置,预测沉积物中的沥青组分可能来自另一套烃源岩——下古生界灰岩。

In order to forecast the hydrocarbon potential of the western part of North Yellow Sea basin （NYSB）, sediment mineral identification,infrared spectrum, and organic gas chromatogram have been used to analyze the bitumen from 542 surface and column samples. The analytical results show that a large quantity of bitumens exist in the west part of NYSB, mainly distributed in the west fine-grained areas with a dominant strike of NNE and a minor NW. The OEP from different depth shows that the submarine sediments encountered a slight oil pollution. On the basis of the existing results of source rocks and pre-Mesozoic basement of NYSB, and according to the distribution of high content bituments, it is inferred that the bitumens could be from another source rock--lower Paleozoic limestone.