江汉盆地潜江凹陷潜江组盐间页岩油储层特征研究——以潜3-10韵律为例

Characteristics of reservoirs for inter-salt shale oil of Qianjiang Formation, Qianjiang Sag, Jianghan Basin: a case study of the E-10 rhythm

刘心蕊 吴世强 陈凤玲 张亮 杜小娟 管文静 梁文川

LIU Xinrui WU Shiqiang CHEN Fengling ZHANG Liang DU Xiaojuan GUAN Wenjing LIANG Wenchuan

中国地质大学(武汉)资源学院, 武汉 430074 中国石化 江汉油田分公司, 武汉 430035

School of Earth Resources, China University of Geosciences(Wuhan), Wuhan, Hubei 430074, China Research Institute of Exploration and Development, SINOPEC Jianghan Oilfield Branch Company, Wuhan, Hubei 430223, China

江汉盆地始新统潜江组盐间页岩油是近年来研究的热点和难点。为了明确盐间页岩储层岩相及其储集物性，综合运用岩心观测、岩石薄片鉴定、X衍射、高压压汞和页岩孔渗等资料，对潜江凹陷潜江组盐间页岩油储层岩相发育特征及其对储集物性的影响进行了研究。该区盐间页岩油储层主要包括富碳纹层状泥质白云岩相、富碳纹层状云/灰质泥岩相和钙芒硝充填富碳纹层状云质泥岩相3种不同类型的岩相类型，前2种岩相的孔隙度明显高于后者。不同岩相孔径分布差异明显，富碳纹层状泥质白云岩相以孔径大于41 nm的孔隙为主，中值孔喉半径为219 nm；而富碳纹层状云/灰质泥岩相和钙芒硝充填富碳纹层状云质泥质相则以孔径小于41 nm的孔隙为主，中值孔喉半径为21 nm。富碳纹层状泥质白云岩相岩性均一，具有良好的储集空间和较大的孔喉结构，页岩储层中的含油性较高，为盐间页岩油储层中的优势岩相，是研究区最有利的页岩油勘探目标。

The inter-salt shale oil of the Eocene Qianjiang Formation in the Jianghan Basin is a hot and difficult research target in recent years. In order to clarify the lithofacies and physical properties of the inter-salt shale reservoirs, based on core observation, thin section observation, X-ray diffraction, high-pressure mercury intrusion and shale porosity and permeability analyses, a case study was carried out for the Qianjiang Formation in the Qianjiang Sag of Jianghan Basin. Results showed that there were three types of lithofacies, including carbonaceous laminar argillaceous dolomites, carbonaceous lamellar dolomitic/lime mudstones and carbonaceous lamellar dolomitic mudstones filled with glauberites. The porosities of the first two lithofacies were significantly higher than that of the latter. The pore size distribution of different lithofacies showed that the carbonaceous laminar argillaceous dolomites were dominated by pores with radius greater than 41 nm, and the median pore-throat radius was 219 nm, while the other two facies were dominated by pores with pore radius less than 41 nm and the median pore-throat radius was 21 nm. The carbonaceous laminar argillaceous dolomites were indicated to be homogeneous in lithology. As reservoir, they have good reservoir space, larger pore-throat structure and higher oil content, and was the dominant facies in the inter-salt shale oil reservoir and is promising to be the most favorable shale oil exploration target in the study area.

国家科技重大专项 2017ZX05049—005

https://doi.org/10.11781/sysydz202102268