川东南志留系龙马溪组页岩储层微孔隙结构及连通性研究

Micro-pore structure and connectivity of the Silurian Longmaxi shales, southeastern Sichuan area

刘伟新 鲍芳 俞凌杰 张文涛 张庆珍 卢龙飞 范明

Liu Weixin Bao Fang Yu Lingjie Zhang Wentao Zhang Qingzheng Lu Longfei Fan Ming

中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 2. 中国石化 油气成藏重点实验室, 江苏 无锡 214126

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China 2. SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms, Wuxi, Jiangsu 214126, China

采用CT扫描、聚焦离子束扫描电镜、氩离子抛光—场发射扫描电镜、透射电镜等技术，对川东南志留系龙马溪组页岩进行了微孔隙结构及连通性分析，提出了4种页岩孔隙结构类型：（1）粒间微孔，存在于矿物颗粒之间，数量较少；（2）粒内微孔，分布于粒间分散有机质中及与球状黄铁矿共生的有机质中，少量见于黏土片间的微孔隙；（3）粒缘隙，存在于分散有机质颗粒及矿物颗粒周缘；（4）层（页）理缝，基本平行于页岩沉积层理较大的微裂隙。有机质纳米孔隙呈蜂窝状，呈正态分布，互相连通，孔隙直径主要在30~90 nm之间；孔隙喉道呈单曲线形，喉道宽度主要在7~20 nm之间；层（页）理缝约占页岩孔隙体积的1%~2%，是页岩的优势渗滤通道。微孔隙主要分布于有机质中，是页岩气的主要储集空间，粒缘隙形成页岩连通网络，层（页）理缝为页岩的主要渗滤通道，提出"纳米孔储集、粒缘隙连通、页理缝渗滤"的页岩气连通与流动模式。

Micro-pore structure and connectivity of the Silurian Longmaxi shales in the southeastern Sichuan Basin were studied using CT, FIB-SEM, Ar+-SEM, and TEM techniques. Four modes for micro-pores in shales were determined to be as follows. (1) Intergranular micro-pores which exist between mineral grains and account for a small proportion of the total. (2) Intragranular micro-pores which mainly exist in intergranular dispersed organic matter or symbiosis organic matter with globular pyrite, and some between clay layers. (3) Grain boundary fractures which exist around organic or mineral grains, and work as a connective network for the shales. (4) Interlayer bedding which provides filtration channels. Intraparticle organic nano-pores are bubble like, show a normal size distribution, and are connected to each other. Their diameter mainly ranges from 30-90 nm and throat width ranges from 7-20 nm. Interlayer bedding accounts for 1%-2% of total shale pores and fractures, and are favorable filtration channels. Micro-pores and fractures in organic matter provide the main reservoir space for shale gas, grain boundary fractures form a connective network, while interlayer bedding provides filtration channels.

国家自然科学基金项目（41372130）和中国石化科技部项目（P13089）资助。

https://doi.org/10.11781/sysydz201604453