Controlling factors and exploration potential of shale gas enrichment and high yield in Permian Dalong Formation, northern Sichuan Basin, SW China

作者：Rui Yong, Hongzhi Yang, Wei Wu, Xue Yang, Yuran Yang, Haoyong Huang · 发表于：Petroleum Exploration and Development · 年份：2025 · DOI：10.1016/s1876-3804(25)60567-2 · 被引用次数：20 · 研究领域：Hydrocarbon exploration and reservoir analysis、Geological Studies and Exploration、Geological and Geophysical Studies

Based on the basic data of drilling, logging, testing and geological experiments, the geological characteristics of the Permian Dalong Formation marine shales in the northern Sichuan Basin and the factors controlling shale gas enrichment and high yield are studied. The results are obtained in four aspects. First, the high-quality shale of the Dalong Formation was formed after the deposition of the Permian Wujiaping Formation, and it is developed in the Kaijiang-Liangping trough in the northern part of Sichuan Basin, where deep-water continental shelf facies and deep-water reduction environment with thriving siliceous organisms have formed the black siliceous shale rich in organic matter. Second, the Dalong Formation shale contains both organic and inorganic pores, with stratification of alternated brittle and plastic minerals. In addition to organic pores, a large number of inorganic pores are developed even in ultra-deep (deeper than 4 500 m) layers, contributing a total porosity of more than 5%, which significantly expands the storage space for shale gas. Third, the limestone at the roof and floor of the Dalong Formation acted as seal rock in the early burial and hydrocarbon generation stage, providing favorable conditions for the continuous hydrocarbon generation and rich gas preservation in shale interval. In the later reservoir stimulation process, it was beneficial to the lateral extension of the fractures, so as to achieve the optimal stimulation performance and increa...