潜江凹陷页岩岩相对页岩油储层的控制作用  

CONTROL OF SHALE LITHOFACIES ON THE SHALE OIL RESERVOIR IN QIANJIANG SAG

作　　者：云念寒 王芙蓉[1] 侯宇光[1] 曾宏斌 杨荣岩 YUN Nian-han;WANG Fu-rong;HOU Yu-guang;ZENG Hong-bin;YANG Rong-yan(Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074

出　　处：《地质与资源》2023年第6期750-761,共12页Geology and Resources

基　　金：国家自然科学基金委员会重点项目“陆相页岩油在基质-裂缝体系中的多尺度运移机理研究”(41830431);国家自然科学基金项目“有机质石墨化对南方下古生界海相页岩有机质孔隙结构的影响”(41772143);科学技术部重大专项资助项目“潜江与泌阳凹陷页岩油勘探开发目标评价”(2017ZX05049-005).

摘　　要：在岩心观察与岩石薄片鉴定的基础上,结合XRD技术、氩离子抛光扫描电镜、低温氮气吸附实验、高压压汞测试和岩石热解分析,对江汉盆地潜江凹陷潜江组页岩储层的岩石矿物组成、孔渗和孔隙结构、地球化学特征等进行分析.研究表明,潜江凹陷潜江组页岩主要矿物组成为白云石和黏土矿物,主要发育块状灰质泥岩相、纹层状灰质泥岩相、块状云质泥岩相、纹层状云质泥岩相以及块状泥质云岩相和纹层状泥质云岩相.页岩储层主要发育碳酸盐矿物晶间孔和黏土矿物层间孔,孔径主要分布在2~200 nm,孔隙度多低于20%,渗透率主要为0.1×10^(-3)~100×10^(-3)μm^(2),为低孔低渗—特低渗储层.其中黏土矿物有利于页岩储层微孔和介孔的发育,白云石有利于大孔发育,且生物成因的白云石有助于有机碳的富集和滞留烃的赋存.储层整体表现为纹层状页岩比块状页岩具有相对较高的孔径、较好的孔隙连通性和含油性,尤其在纹层状泥质云岩相中,孔隙度介于5%~15%,渗透率处于1×10^(-3)~10×10^(-3)μm^(2),主要孔径为50~200 nm,连通孔径主要为50~100 nm,TOC含量在1%~3%,S1含量分布在5×10^(-3)~35×10^(-3),OSI值多处于400×10^(-3),是潜江组页岩油储层的优势岩相.The rock mineral compositions,porosity-permeability,pore structure and geochemical characteristics of the shale reservoir of Qianjiang Formation in Qianjiang Sag,Jianghan Basin,are studied on the basis of core observation and rock slice identification,combined with XRD technology,argon ion polishing scanning electron microscopy,low temperature nitrogen adsorption experiment,high pressure Hg injection test and rock pyrolysis analysis.The results show that the shale of Qianjiang Formation is mainly composed of dolomite and clay minerals,developed with massive calcareous mudstone facies,laminated calcareous mudstone facies,massive dolomitic mudstone facies,laminated dolomitic mudstone facies,massive argillaceous dolomite facies and laminated argillaceous dolomite facies.The carbonate mineral intercrystalline pores and clay mineral interlayer pores are mainly developed in the shale reservoir,with the pore size of 2-200 nm,the porosity mostly lower than 20%,and the permeability of 0.1×10^(-3)-100×10^(-3)μm^(2),belonging to low porosity and low-extra low permeability reservoir.Clay minerals are conducive to the development of micropores and mesopores in shale reservoirs,while the dolomites contribute to the development of macropores,and biogenic dolomites help the accumulation of organic carbon and occurrence of residual hydrocarbon.Generally,the laminated shale has higher pore size,better pore connectivity and oil content than the massive shale dose.Especially the laminated argillaceous dolomite facies,with porosity of 5%-15%,permeability of 1×10^(-3)-10×10^(-3)μm^(2),main pore size of 50-200 nm,connected pore size of 50-100 nm,TOC content of 1%-3%,S1 content of 5×10^(-3)-35×10^(-3)and OSI value mostly 400×10^(-3),is the dominant lithofacies of shale oil reservoir in Qianjiang Formation.

关 键 词：页岩油储层 孔隙结构 页岩岩相 潜江组 潜江凹陷 江汉盆地 

分 类 号：P618.13[天文地球—矿床学]