鄂尔多斯盆地佳县地区本溪组—下石盒子组致密砂岩储层差异化成岩特征及成储效应  

Differential diagenetic characteristics and its reservoir formation effect of tight sandstone in the Benxi-Lower Shihezi formations in Jiaxian area,Ordos Basin

作　　者：梁状 刘钰铭[1,2] 陈齐 张皓惟 刘沛沛 刘新强 LIANG Zhuang;LIU Yuming;CHEN Qi;ZHANG Haowei;LIU Peipei;LIU Xinqiang(National Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;College of Geoscience,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]油气资源与工程全国重点实验室,中国石油大学(北京),北京102249 [2]中国石油大学(北京)地球科学学院,北京102249

出　　处：《天然气地球科学》2025年第1期97-113,共17页Natural Gas Geoscience

基　　金：国家自然科学基金(编号:42172154)资助.

摘　　要：针对鄂尔多斯盆地佳县地区致密砂岩气勘探亟待解决的地质问题,揭示储层差异化成岩作用与储层质量的作用关系,利用铸体薄片观察、扫描电镜分析、X射线衍射、流体包裹体岩相学相结合,细致对比不同层位的储层特征、成岩作用类型及特征的差异性,建立佳县地区差异化成岩过程模式。结果表明:本溪组—下石盒子组盒8段储层经历了强烈的压实作用、3期胶结作用和2期溶蚀作用,其中压实作用是导致储层致密化的主要因素,而溶蚀作用则对储层质量有显著改善作用。不同层位的成岩作用强度、致密化过程序列明显存在差异,山2段与本溪组为含煤系底层,距离烃源岩近,经历2期溶蚀作用,次生孔隙发育;太原组多套厚层泥晶灰岩,消耗部分酸性成岩流体,溶蚀作用强度稍弱;下石盒子组盒8段经历强烈压实作用及2期胶结作用,孔隙已基本被填充,且距离源岩较远,晚期溶蚀作用不发育,总体物性较差。明确致密储层差异化成岩特征与储层质量关系,对筛选有利区具有重要的实际意义。To address the geological challenges in tight sandstone gas exploration in Jiaxian area of the Ordos Ba⁃sin,this study aims to reveal the relationship between differential diagenetic processes and reservoir quality,us⁃ing a combination of thin section observations,scanning electron microscopy analysis,X-ray diffraction,and flu⁃id inclusion petrography.Detailed comparisons of reservoir characteristics and differential diagenetic types and features were made among different stratigraphic layers,ultimately establishing a differential diagenetic model for the Jiaxian area.The results indicate that the He 8 section of Lower Shihezi Formation to Benxi Formation reservoirs have experienced intense compaction,two episodes of cementation,and two episodes of dissolution.Compaction is identified as the primary factor contributing to reservoir tightness,while dissolution significantly improves reservoir quality.The intensity and sequence of diagenetic processes vary among different stratigraphic layers.The Shan 2 Member and Benxi Formation,as the lowermost part of the coal-bearing series and in close proximity to the source rocks,have undergone two episodes of dissolution,leading to secondary porosity devel⁃opment.The Taiyuan Formation consists of multiple thick layers of mudstone and limestone,which consume some acidic diagenetic fluids,resulting in a slightly weaker dissolution intensity.The He 8 Member of the Low⁃er Shihezi Formation has undergone intense compaction and two episodes of cementation,with primary porosity mostly filled and limited development of secondary dissolution due to its distant proximity to the source rocks,resulting in overall poor reservoir properties.Understanding the differential diagenetic characteristics and their relationship with reservoir quality in tight reservoirs is of great practical significance for identifying favorable ar⁃eas for exploration and production.

关 键 词：鄂尔多斯盆地 上古生界 致密砂岩 储层质量 差异化成岩特征 

分 类 号：TE122.1[石油与天然气工程—油气勘探]