黄河口凹陷烃源岩有机地球化学特征分析

Organic Geochemical Characteristics of Source Rocks in Huanghekou Sag

为了揭示黄河口凹陷不同层段烃源岩供烃潜力,利用8000余组总有机碳、岩石热解、氯仿沥青“A”、有机元素、镜质体反射率等数据,对12个层段的有机质丰度、有机质类型和成熟度进行分析对比。研究发现,沙三中、沙三下亚段有机质丰度最高,达到极好烃源岩标准;沙一段、沙二段、东三段、沙三上为好烃源岩;沙四-孔店组、东二下亚段、东一段为中等—差烃源岩,东二上亚段、明化镇组与馆陶组未达到烃源岩标准。黄河口凹陷烃源岩有机质类型总体偏腐殖型。其中,沙三中、沙三下、沙一—二段、东三段相对较好,沙三上、沙四-孔店组、东二上、东二下有机质类型普遍较差,主要是Ⅱ_(2)—Ⅲ型。沙四-孔店组烃源岩整体处于成熟—高成熟演化阶段,沙河街组烃源岩整体处于生油窗范围,东营组烃源岩处于未熟—低熟阶段。综合有机质丰度、有机质类型和成熟度指标认为,沙三中、沙三下烃源岩最优,沙一二段、沙三上、沙四-孔店组烃源岩次之,东营组还不能大规模供烃。

In order to reveal the hydrocarbon supply potential of source rocks in different layers in Huanghekou Sag,more than sets of data,including total organic carbon,rock pyrolysis analysis,chloroform bitumen"A",organic elements,vitrinite reflectance,etc.are used to analyze and compare the abundance,type and maturity of organic matter in 12 layers.The results show that Es3^(m) and Es3^(l) are high-quality source rocks with the highest organic abundance;Es1,Es2,Ed3 and Es3^(u) are good source rocks;Es4-Ek,Ed2^(l) and Ed1 are source rocks with medium to poor quality,while Ed2^(u),Nm and Ng are not the source rocks.The organic matter of the source rocks in Huanghekou Sag is generally humic type.The organic matter in Es3^(m),Es3^(l),Es1-2 and Ed3 has good organic matter type,while the organic matter in Es3^(u),Es4-Ek,Ed2^(u) and Ed2^(l) is Ⅱ_(2)-Ⅲ type,which is poor type.Es4-Ek source rocks are generally in mature-highly mature evolution stage.The source rocks of the Shahejie formation are in the range of oil generation window,and the Dongying formation is in immature-low mature evolution stage.According to the analysis of organic matter abundance,type and maturity indexes,it is held that the source rocks of Es3^(m) and Es3^(l) are the best,followed by the source rocks of Es1-2,Es3^(u),Es4-Ek.The Dongying formation is currently unable to supply hydrocarbon on a large scale.