陇东地区延长组层序地层特征及油气勘探意义  

Sequence stratigraphic characteristics of the Yanchang Formation in the Longdong area and their significance for petroleum exploration

作　　者：郭艳琴[1] 李文厚[2] 陈全红[2] 梁积伟[2] 余芳[2] 何卫军[2] 

机构地区：[1]西安石油大学油气资源学院,陕西西安710065 [2]西北大学地质学系,陕西西安710069

出　　处：《中国地质》2007年第3期406-413,共8页Geology in China

基　　金：国家重点基础研究发展计划(973)项目(2003CB214602)资助。

摘　　要：综合应用测井曲线、岩心、野外露头剖面等资料,分析鄂尔多斯盆地陇东地区延长组的层序地层特征及沉积相,在延长组识别出4个三级层序界面,将延长组分为4个三级层序10个体系域,识别出4种主要的沉积体系:扇三角洲、辫状河三角洲、曲流河三角洲及湖泊沉积体系。分析了各体系域沉积体系的平面展布特征,探讨了体系域沉积模式及层序与油气的关系。指出低位体系域中发育的三角洲平原河道及前缘水下分流河道砂体是最主要的储层,水进及高位体系域中发育的浊积岩砂体分布面积大,是潜在的储层、水进和高位体系域中发育的湖相泥、页岩是良好的生油层和盖层,使得陇东地区存在有利的生储盖组合,处于有利的含油气系统之中,具较好的油气勘探前景。Based on data of logs, cores and outcrops, the characteristics of the stratigraphic sequence and sedimentary facies of the Yanchang Formation in the Longdong area, Ordos basin, are studied. Four third-order sequence boundaries are recognized in the formation. The authors divide the formation into four third-order depositional sequences and ten systems tracts. Four main depositional systems are identified： the fan delta, braided river delta, meandering river delta and lacustrine sedimentary systems. The distribution characteristics of the deposifional systems in various systems tracts are analyzed and the deposifional models of the systems tracts and the relationship between depositional sequences and petroleum are also discussed. The authors think that the sand bodies in channels of the delta plain and subaqueous distributary channels in the delta front in the lowstand systems tracts are main reservoirs, the sand bodies of turbidites in transgressive and highstand systems tracts are potential reservoirs, and the lacustrine mudstone and shale developed in transgressive and highstand systems tracts are good source rocks and cap rocks-aU these show that the Longdong area is located in a favorable petroleum-bearing system with favorable source-reservoir-cap assemblages and has good petroleum prospects.

关 键 词：层序地层 沉积体系 延长组 陇东地区 

分 类 号：P539.2[天文地球—古生物学与地层学] TE121.34[天文地球—地质学]