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鄂尔多斯盆地中部志丹—吴起地区延长组长10油层组顶部发育一套湖相暗色泥岩,确定该套烃源岩的地质地球化学特征及生烃潜力对该区油气勘探有重要意义。利用岩心和测井资料,研究了长10暗色泥岩的分布特征,通过开展岩石热解、干酪根显微组分、镜质体反射率、可溶有机质族组分及饱和烃色谱—质谱等有机地球化学测试和分析,评价了长10烃源岩的生烃潜力。研究表明,长10暗色泥岩分布广泛,厚度为5～20m;烃源岩有机质丰度和生烃转化率较高,有机质母质中陆源植物生源贡献较大,主要为Ⅱ型和Ⅲ型干酪根,有机质热演化程度达到成熟生油阶段,总体评价为较好—好烃源岩。长10烃源岩的生物标志化合物特征有别于长7烃源岩和长9烃源岩,具有高Pr/Ph值、ααα20R构型C27、C28和C29规则甾烷呈反“L”型分布的典型特征。长10烃源岩的生烃量较大,是鄂尔多斯盆地中生界另外一套重要的有效烃源岩,该套烃源岩的发现为鄂尔多斯盆地中部延长组下组合的深入勘探提供了科学依据。
It is of great significance to determine the geo-geochemical characteristics and hydrocarbon generation potential of this set of source rocks to develop a set of lacustrine dark mudstone at the top of Chang 10 oil layer of Yanchang Formation in the Zhidan-Wuqi area in the central Ordos Basin. Based on the core and well logging data, the distribution characteristics of the Chang 10 dark mudstone were studied. Through the pyrolysis of rocks, kerogen microstructure, vitrinite reflectance, soluble organic components and saturated hydrocarbon chromatography - mass spectrometry Geochemical tests and analyzes to evaluate the hydrocarbon potential of the Chang 10 source rock. The results show that the Chang 10 dark mudstone is widely distributed and has a thickness of 5-20 m. The organic matter abundance and hydrocarbon conversion rate of the source rock are high, and the terrigenous source of organic matter in the organic matter parent contribute more to the source, mainly Type II and III kerogens, The extent of thermal evolution of organic matter reaches the stage of mature oil generation, and the overall evaluation is better - good source rocks. The characteristics of biomarkers of Chang 10 source rock are different from that of Chang 7 and Chang 9 source rocks, and have high Pr / Ph values. The α27α, C28, and C29 regular steranes show a characteristic of “L” Typical Features of Pattern Distribution. The Chang 10 source rock has a large amount of hydrocarbon generation and is another important source rock of the Mesozoic in the Ordos Basin. The discovery of this set of source rocks provides a scientific basis for further exploration of the Yanchang Formation in the central Ordos Basin .