鄂尔多斯盆地东南部长6段致密砂岩孔喉结构及演化  

Pore Throat Structure and Evolution in Chang 6 Tight Sandstone Reservoirs in Southeastern Ordos Basin

作　　者：严敏 赵靖舟 黄延昭[1,2] 杨振亚 方越 吴和源 YAN Min;ZHAO Jingzhou;HUANG Yanzhao;YANG Zhenya;FANG Yue;WU Heyuan(Northwest University,Department of Geology,Xi’an,Shaanxi 710069,China;Northwest University,State Key Laboratory of Continental Dynamics,Xi’an,Shaanxi 710069,China;Xi’an Shiyou University,School of Earth Sciences and Engineering,Xi’an,Shaanxi 710065,China;Xi’an Shiyou University,Shaanxi Key Laboratory of Hydrocarbon Accumulation Geology,Xi’an,Shaanxi 710065,China;No.5 Oil Production Plant,Changqing Oilfield Company,PetroChina,Xi’an,Shaanxi 710299,China)

机构地区：[1]西北大学地质学系,西安710069 [2]西北大学大陆动力学国家重点实验室,西安710069 [3]西安石油大学地球科学与工程学院,西安710065 [4]西安石油大学陕西省油气成藏地质学重点实验室,西安710065 [5]中国石油长庆油田分公司第五采油厂,西安710299

出　　处：《新疆石油地质》2023年第6期674-682,共9页Xinjiang Petroleum Geology

基　　金：陕西省自然科学基础研究计划项目(2020JQ-767);陕西省教育厅重点科学研究计划项目(20JS128)。

摘　　要：通过铸体薄片、扫描电镜、全岩与黏土矿物X射线衍射、高压压汞、CT扫描等分析测试手段,对鄂尔多斯盆地东南部长6段非均质致密砂岩储集层的成岩-孔隙动态演化开展研究,在此基础上,讨论不同储集空间的成岩-孔喉演化特征。研究区长6段储集层的储集空间分为残余原生粒间孔主导型、溶蚀孔主导型和混合孔型3种;矿物成分和结构成熟度制约储集层的初始孔喉结构;胶结作用及其强度影响储集层的致密程度;溶蚀作用产生的孔喉影响储集性能。若储集层主要受压实作用和绿泥石胶结作用影响,则残余原生粒间孔占主导,孔隙孤立,多表现为中孔-疏网状喉道型储集空间,孔隙度较高,但连通性较差;若受浊沸石胶结和强溶蚀作用影响,则浊沸石溶蚀孔占主导,连通性好,多表现为中孔-类树状喉道型储集空间,为最佳储集空间;储集层经历绿泥石胶结、浊沸石胶结—弱溶蚀作用后,受浊沸石溶蚀孔与残余原生粒间孔共同影响,连通性较好,多表现为微孔、中孔-密网状喉道型储集空间,储集性能介于前两者之间。Based on the analyses of cast thin section,scanning electron microscopy(SEM),X⁃ray diffraction(XRD)of whole rock and clay minerals,high⁃pressure mercury intrusion,and CT scanning,a detailed study was conducted on the dynamic diagenesis⁃pore evolution of the Chang 6 heterogeneous tight sandstone reservoirs in the southeastern Ordos basin.Then the characteristics of diagenesis and porethroat evolution of different reservoir spaces were discussed.The accommodation of Chang 6 reservoir in the study area is classified into 3 types such as reservoir spaces dominated by residual primary intergranular pores,dominated by dissolution pores,and mixed pores.The mineral composition and textural maturity control the initial pore⁃throat structure of the reservoir,cementation and its intensity influence the tightness of the reservoir,and the pore throats formed due to dissolution affect reservoir storage performance.If the reservoir is mainly affected by compaction and chlorite cementation,then residual primary intergranular pores are dominant,and the fractures are isolated,mostly leading to reservoir spaces consisting of mesopores with sparse reticular throats,indicative of good storage but poor connectivity.If the reservoir is influenced by zeolite cementation⁃strong dissolution,then zeolite dissolution pores are dominant,resulting in excellent pore throat connectivity,often appearing as reservoir spaces consisting of mesopores with tree⁃like throats,indicative of the optimal accommodation.If the reservoir has undergone cementation of chlorite,and cementation⁃weak dissolution of zeolite,both zeolite dissolution pores and residual primary intergranular pores contribute to relatively good pore throat connectivity,often exhibiting reservoir spaces consisting of micropores to mesopores with dense reticular throats,with the storage and transportation capacity falling between the above mentioned two.

关 键 词：鄂尔多斯盆地 延长组 长6段 致密砂岩储集层 储集空间 微观孔喉结构 高压压汞 CT扫描 

分 类 号：TE122.2[石油与天然气工程—油气勘探]