【摘要】 通过烃源岩沉积特征及地球化学实验数据分析,对鄂尔多斯盆地西南缘中上奥陶统烃源岩分布和生烃潜力进行了系统评价。鄂尔多斯盆地西南缘奥陶系烃源岩主要发育在中上奥陶统克里摩里组和乌拉力克组,呈"L"字形围绕中央古隆起分布;它们为一套厚度较大的深水相泥页岩和含泥灰岩沉积。烃源岩生烃母质类型以Ⅰ型干酪根为主,Ⅱ1型次之。有机碳丰度在不同层位不同岩性均有差别;从层位上来看,乌拉力克组和克里摩里组烃源岩TOC平均值分别为0.58%和0.50%,达到中等烃源岩生烃标准;从岩性上来看,泥质烃源岩有机质丰度高于含泥碳酸盐岩。除沙井子地区为低成熟阶段外,鄂尔多斯盆地中上奥陶统海相烃源岩热成熟度均处于高成熟—过成熟阶段。鄂尔多斯盆地中上奥陶统海相烃源岩生烃量合计达48×1012 m3,总资源量为2.3×1012 m3,西部天环北地区和南部淳化地区为2个生烃中心,是下一步勘探的重点方向。更多还原

【Abstract】 Source rocks of the Middle-Upper Ordovician in the western and southern margin of the Ordos Basin were evaluated systematically through analysis of its characteristics in petrology and geochemistry. The source rocks mainly developed in the Kelimoli Formation and the Wulalike Formation,distributed as "L"surrounding the central ancient uplift,which was a thick shale and muddy limestone deposition of deepwater facies.The main kerogen type is type I,and the secondary is typeⅡ1.The TOCvaries in different strata or in different lithology.The average TOCof source rocks in Wulalike Formation and Kelimoli Formation is 0.58%and 0.50%,respectively,which is a kind of medium source rocks according to the evaluation criterion.The TOCin shale is higher than that in muddy carbonate hydrocarbon source rocks in consideration of the lithology.The organic matters in source rocks are in the high-over maturity stage and the kerogen is in the gas-generation stage excepted Shajingzi district.The generated gas amount in the Middle- Upper Ordovician adds up to 48×1012 m3 and the total resources are 2.3×1012 m3.There are two hydrocarbon generation centers,which are northern Tianhuan district in the west margin and Chunhua district in the south margin.The two districts will be the favorable exploration targets in the future.更多还原