湖泊深水重力流沉积露头精细解剖——以鄂尔多斯盆地瑶曲剖面长7油层组为例

发布时间：2018-02-11 22:27

本文关键词： 沉积露头岩相类型垂向组合湖泊深水重力流长段鄂尔多斯盆地　出处：《地质学报》2017年03期 　论文类型：期刊论文

【摘要】：沉积露头为精细刻画沉积体内部结构、建立准确地下地质模型发挥着不可替代的作用。本文以鄂尔多斯盆地南部瑶曲剖面长7段为例,采用地质学、野外露头沉积学方法,详细剖析了湖泊深水重力流沉积深水岩相的类型、特征、垂向组合及沉积环境。研究表明,瑶曲剖面长7段发育块状细砂岩相、鲍马序列粉砂岩相、水平纹理泥岩相、块状泥岩相、水平层理页岩相、凝灰岩相6种岩相类型,碎屑流沉积、浊流沉积、滑塌沉积、深水原地沉积、火山碎屑沉积5类沉积单元,在垂向上5类沉积单元构成了A、B、C、D 4类垂向分布形式。在此基础上,结合区域地质特征,研究认为长7段发育湖泊、水道型重力流沉积两种沉积体系。湖泊相可进一步确定为半深湖—深湖亚相,深水原地沉积微相,以D类岩相组合最为发育;水道型重力流沉积体系进一步划分为近源水道、远源水道、堤岸、前端朵体4个亚相,包含砂质碎屑流沉积、浊流沉积、滑塌沉积3个微相,近源水道+堤岸形成A类、C类、B类岩相组合,远源水道+堤岸形成B类、C类岩相组合,前端朵叶发育C类岩相组合。剖面相分析表明,研究区优质的烃源岩与重力流砂体可构成较好的"下生上储"的致密岩性油气藏。
[Abstract]:The sedimentary outcrop is a fine description of the internal structure of the sedimentary body and plays an irreplaceable role in the establishment of an accurate geological model. Taking Chang7 member of the Yao qu section in the southern Ordos Basin as an example, geological and outcrop sedimentology methods are used in this paper. The types, characteristics, vertical assemblage and sedimentary environment of deep-water lithofacies in lake deep water gravity flow deposition are analyzed in detail. The results show that block fine sand facies, Baoma sequence siltstone facies, horizontal texture mudstone facies are developed in Chang7 member of Yao qu section. Block mudstone facies, horizontal bedding shale facies, tuff facies 6 types of lithofacies, clastic flow deposits, turbidite deposits, sloughing deposits, deep-water in-situ deposits, pyroclastic deposits, 5 types of sedimentary units, On the basis of the vertical distribution of the five types of sedimentary units in the vertical direction, the authors consider that the Chang 7 member has developed lakes, on the basis of the vertical distribution of the five types of sedimentary units, and in combination with the regional geological characteristics, it is considered that the Chang 7 member has developed lakes. The lacustrine facies can be further determined as semi-deep lacustry-deep lacustrine subfacies, and deep-water in-situ sedimentary microfacies, with D lithofacies assemblage being the most developed, and the watercourse gravity flow sedimentary system can be further divided into near-source channels. There are 4 subfacies of the far source channel, the bank of the dike and the front end of the body, which contain three microfacies: sand clastic flow deposition, turbidite flow deposition and sloughing deposit. The near source water channel embankment forms the A / C type B lithofacies assemblage. B type C lithofacies assemblage is formed along the bank of the far source water channel, and C type lithofacies assemblage is developed in the front flower leaf. The surface facies analysis shows that the high quality hydrocarbon source rock and gravity flow sand body in the study area can form a good tight lithologic reservoir with "lower generation and upper reservoir".
【作者单位】：非常规油气湖北省协同创新中心(长江大学);长江大学地球科学学院;低渗透油气田勘探开发国家工程实验室;中国石油长庆油田公司;中国石油长庆油田公司勘探开发研究院;
【基金】：国家自然科学基金项目(编号41672099) 国家重点基础研究发展计划"973"项目(编号2014CB239003)联合资助成果
【分类号】：P618.13

【相似文献】