鄂尔多斯盆地西南缘中上奥陶统烃源岩特征及勘探潜力  

Geochemical Characteristics and Exploration Potential of the Middle-Upper Ordovician Source Rocks on the Western and Southern Margin of Ordos Basin

作　　者：张月巧[1,2] 郭彦如[2] 侯伟[1,3] 赵振宇[2] 高建荣[2] 

机构地区：[1]中国地质大学能源学院,北京100083 [2]中国石油勘探开发研究院鄂尔多斯分院,北京100083 [3]中国石油煤层气有限责任公司,北京100028

出　　处：《天然气地球科学》2013年第5期894-904,共11页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2011ZX05004-002);中国博士后科学基金资助项目(编号:2012T50121)联合资助

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。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 ＂I.＂ surrounding the central ancient uplift,which was a thick shale and muddy limestone deposition of deep water facies. The main kerogen type is type I,and the secondary is type II 1. The TOC varies in different strata or in different lithology. The average TOC of source rocks in Wulalike Formation and Kelimoli For- mation is 0. 58% and 0.5% ,respectively,which is a kind of medium source rocks according to the evalua- tion criterion. The TOC in shale is higher than that in muddy carbonate hydrocarbon source rocks in con sideration 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 48×10^12m3 and the total resources are 2.3 ×10^12m3. There are two hydrocar bon generation centers, which are no south margin. The two districts will rth be the favorable exploration targets in the future.

关 键 词：鄂尔多斯盆地 海相烃源岩 中上奥陶统 资源潜力 

分 类 号：TE122.112[石油与天然气工程—油气勘探]