鄂尔多斯盆地华池地区三叠系延长组长7段富有机质页岩岩相特征

发布时间：2018-03-04 09:12

本文选题：富有机质页岩　切入点：岩相　出处：《地学前缘》2016年02期 　论文类型：期刊论文

【摘要】：鄂尔多斯盆地三叠系延长组长7油层组发育富有机质页岩和泥岩,目前已成为鄂尔多斯盆地页岩油气勘探的重要层位。综合岩心精细描述、薄片微观结构观察和粒度分析结果,将富有机质页岩和泥岩划分为黑色页岩岩相、纹层状泥岩岩相、粉砂质泥岩岩相。粉砂质泥岩岩相的脆性矿物含量高于黑色页岩岩相和纹层状泥岩岩相,后者比前者具有更高的黄铁矿含量,3种岩相的黏土矿物含量较接近。黑色页岩岩相有机质丰度高,有机质类型以I型干酪根为主,是最有利的富有机质岩相类型,其次为纹层状泥岩岩相。长7油层组沉积时期水体为分层的厌氧环境,有利于有机质的保存,低等水生生物是主要的母质来源。黑色页岩岩相和纹层状泥岩岩相形成于安静、缺少陆源碎屑影响的深湖环境下;粉砂质泥岩岩相形成于受陆源碎屑频繁影响的环境,有较多的陆源高等物质输入湖盆中,造成有机质类型复杂。将岩心精细描述和测井信息紧密结合,揭示了各类岩相纵向发育特征。受基准面变化和沉积物供给能力影响,长73以黑色页岩岩相和纹层状泥岩岩相为主,长72和长71以纹层状泥岩岩相和粉砂质泥岩岩相为主。长73暗色泥岩和页岩的岩相类型好,发育页理缝和纹层缝,有机质类型好、丰度高,是最有利的页岩油气勘探目的层系。
[Abstract]:Organic matter rich shale and mudstone are developed in the formation of Chang 7 of the Triassic Yanchang formation in Ordos Basin, which has become an important horizon for oil and gas exploration of shale in Ordos Basin at present. The organic matter rich shale and mudstone are divided into black shale facies, lamellar mudstone facies, silty mudstone lithofacies. The brittle mineral content of silty mudstone facies is higher than that of black shale facies and lamellar mudstone facies. The latter has higher pyrite content than the former, and the clay mineral content of the three lithofacies is similar. The black shale facies has high organic matter abundance, and the organic matter type is dominated by type I kerogen, which is the most favorable lithofacies with rich organic matter. Secondly, the stratiform mudstone facies. The water body of Chang 7 oil formation is stratified anaerobic environment, which is favorable for the preservation of organic matter. The low aquatic life is the main source of parent material. The black shale facies and lamellar mudstone facies are formed in quiet. The silty mudstone facies are formed in the environment which is frequently influenced by continental clastic, and there is more material input into the lake basin. Because of the complexity of organic matter types, the fine core description and logging information are closely combined to reveal the longitudinal development characteristics of various lithofacies, which are affected by the change of datum level and the supply capacity of sediment. Chang73 is dominated by black shale facies and lamellar mudstone facies, Chang72 and Chang71 by lamellar mudstone facies and silty mudstone facies. High abundance is the most favorable target series for shale oil and gas exploration.
【作者单位】：西安石油大学地球科学与工程学院;西安石油大学陕西省油气成藏地质学重点实验室;中国石油长庆油田分公司勘探开发研究院;低渗透油气田勘探开发国家工程实验室;
【基金】：陕西省自然科学基金项目(2013JQ503) 陕西省教育厅重点科研项目(15JS092) 国家油气重大专项(2011ZX5018001;2011ZX05001;2011ZX05044)
【分类号】：P618.13

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