关键词: 四川盆地, 侏罗系, 陆相页岩, 富集条件, 勘探开发有利区

Abstract: Three sets of bathyal lacustrine organic-rich shale are developed in the Jurassic of Sichuan Basin, characterized by superposed development and broad distribution; the bathyal lacustrine shale is characterized by "high TOC, high porosity and high gas content". Recently, new breakthroughs have been made in the exploration of continental shale oil and gas in multiple wells and sections of the Jurassic in Sichuan Basin, boasting of great exploration potential and abundant resources, which are key replacement resources instead of the marine shale gas in Wufeng Formation and Longmaxi Formation. Through comprehensive evaluation of fine-grained rocks, it is found that the continental shale oil and gas have strong heterogeneity. On this basis, a quaternary lithofacies division scheme was established to clarify the main controlling factors for the enrichment and high production of continental shale oil and gas. Specifically, the bathyal lacustrine organic-rich shale provides the material base, good tectonic preservation and high-pressure conditions are the key conditions, appropriate thermal evolution and microfracture development are conducive to hydrocarbon enrichment and flow, and the geology-engineering integrated research can guarantee high production. The Jurassic continental shale oil and gas resources have great potential, with the natural gas equivalent of 6.0×10¹²m³, accounting for 27.7% of the total natural gas resources in Sichuan Basin. This is an important field for increasing reserves and production during the "14th Five-Year Plan" period (2021-2025). Multilayer superimposed shale is developed and bathyal lacustrine shale distributes extensively in northeastern Sichuan, which are important favorable zones for exploration. Sinopec has the total natural gas resources of 2.94 × 10¹²m³ and crude oil of 12.03×10⁸ t in these areas, which are important replacement resource fields for oil-gas exploration and development in Southwest China. The exploration and development of continental shale oil and gas in Sichuan Basin is still in the early stage, and there are still deficiencies in research of fine-grained rock sedimentary reservoirs, reservoir properties, main controlling factors of enrichment and high production, and applicable engineering fracturing technology. It is still necessary to make more efforts to tackle key scientific and technical problems and practice deeply, and strive to achieve greater breakthroughs in the exploitation of continental shale oil and gas in Sichuan Basin during the "14th Five-Year Plan" period and increase reserves and production on a large scale.

Key words: Sichuan Basin, Jurassic, continental shale, enrichment conditions, favorable areas for exploration and development