四川盆地上二叠统海陆过渡相和深水陆棚相页岩气的勘探潜力

Exploration potential of marine-continental transitional and deep-water shelf shale gas in Upper Permian, Sichuan Basin

赵培荣 高波 郭战峰 魏志红

ZHAO Peirong GAO Bo GUO Zhanfeng WEI Zhihong

中国石化 油田勘探开发事业部, 北京 100728 中国石化 石油勘探开发研究院, 北京 100083 中国石化 江汉油田分公司, 湖北 潜江 433124 中国石化 勘探分公司, 成都 610041

Oilfield Exploration & Development Department, SINOPEC, Beijing 100728, China SINOPEC Petroleum Exploration & Production Research Institute, Beijing 100083, China SINOPEC Jianghan Oilfield Company, Qianjiang, Hubei 433124, China SINOPEC Exploration Company, Chengdu, Sichuan 610041, China

四川盆地上二叠统发育海陆过渡相和深水陆棚相两种类型富有机质页岩，其中海陆过渡相含煤页岩层系主要分布于成都-南充-广安-石柱-涪陵一线以南的龙潭组，页岩单层厚度薄，但累计厚度大，干酪根类型以Ⅲ型为主，现今处于高-过成熟阶段；页岩储集空间以黏土矿物孔、粒间孔、微裂缝为主，有机质孔不发育，页岩含气性好，但由于页岩黏土矿物含量高、脆性矿物含量较低，可压裂性较差，需要进一步攻关适应性工程工艺技术。深水陆棚相富有机质页岩主要分布于四川盆地北部广元-巴中-宣汉-云阳-石柱一带的吴家坪组和大隆组，其中吴家坪组页岩厚度20~80 m，大隆组页岩厚度10~40 m，有机碳含量普遍大于2%，有机质类型以Ⅱ1型为主，处于高成熟-过成熟阶段；页岩储集空间以有机质孔和粒内孔为主，储集性能好，硅质矿物含量高、黏土矿物含量较低，页岩可压裂性好，是四川盆地页岩气勘探的重要领域。

Two types of organic-rich shale, i.e. marine-continental transitional shale and deep-water shelf shale, are well developed in the Upper Permian of the Sichuan Basin. The coal-bearing shale of the marine-continental transitional facies is primarily distributed in the Longtan Formation to the south of Chengdu-Nanchong-Guang'an-Shizhu-Fuling, which has thin individual layers but is cumulatively thick. It is dominated by type Ⅲ kerogen in the high-maturity to over-mature stage. The shale reservoir is primarily composed of clay-mineral-hosted pores, intergranular pores and micro fractures, with a small amount of organic porosity. However, the high clay mineral content and low brittle mineral content result in poor fracturing performance, requiring further engineering work. The organic-rich shale of the deep-water shelf facies is mainly distributed in the Wujiaping and Dalong formations along Guangyuan-Bazhong-Xuanhan-Yunyang-Shizhu in the northern part of the Sichuan Basin, where the Wujiaping and Dalong shales are 20-80 m and 10-40 m thick, respectively. These two shales are rich in organic matter with TOC contents higher than 2%, which are dominated by type Ⅱ1 kerogen at the high-maturity to over-mature stage. The storage space is mainly contributed by organic pores and intragranular dissolution porosity with good storage performance. High siliceous mineral content and low clay mineral content give rise to good fracturing performance, indicating for a good shale gas exploration potential in the Sichuan Basin.

国家自然科学基金企业创新发展联合基金项目“海相深层油气富集机理与关键工程技术基础研究” U19B6003

https://doi.org/10.11781/sysydz202003335