| Author's Name: ZHANG Qin1,2,3, QIU Zhen1,2,3, LIANG Feng1,2,3, LIU Wen1,2,3, KONG Weiliang1,2,3,
WANG Yuman1,2,3, PANG Zhenglian1, GAO Wanli1,4, CAI Guangyin1,2,3,
QU Tianquan1,4, JIANG Chong1,4 |
| Institution: 1. PetroChina Research Institute of Petroleum Exploration and Development；2. National Energy Shale Gas
Research and Development (Experiment) Center；3. CNPC Key Laboratory of Coal-rock Gas； |
| Abstract: |
| Three marine shale formations of the Middle-Upper Permian—the Gufeng Formation (P2g), the 3rd member of
the Wujiaping Formation (P3w3) and the 1st member of the Dalong Formation (P3d1), are well developed in the northeastern
Sichuan Basin, representing promising new targets for enhancing shale gas reserves and production. Based on extensive
core testing data, this study analyzes their geochemical characteristics, reservoir features and proposes corresponding
development strategies to provide theoretical support for shale gas exploration in China. The key findings are as follows: (1) All three shale formations exhibit high organic matter abundance, with average total organic carbon (TOC) contents of
9.82% (P2g), 6.60% (P3w3) and 6.01%(P3d1), respectively. The organic matter is classified as type II1, and the maturity(Ro)
exceeds 2.0%, indicating significant hydrocarbon generation potential. The Gufeng Formation is dominated by siliceous
shale and calcareous shale facies, whereas P3w3 and P3d1 primarily consist of siliceous shale and mixed shale facies. The
brittleness index of all three formations exceeds 70%. Organic pores are the dominant pore type, with mesopores serving
as the primary pore category. (2) The P3w3 exhibits well-developed laminated fractures, highest pore connectivity index
(average value of 5.17), high porosity and high gas content; the P2g has moderate pore connectivity index (average value
of 2.57), high porosity and gas content; the P3d1 shows poor laminated fracture development, the lowest pore connectivity
index(average value of 1.69), the lowest porosity value and relatively high gas content. (3) Compared to the Longmaxi
Formation in southern Sichuan Basin, these three shale formations are characterized by high TOC content, high brittleness
index, high gas content, thin thickness and deep burial depth. Targeted development technologies are thus required.
Favorable areas for shale gas enrichment of these three formations are primarily distributed in the southeastern segment of
the Kaijiang-Liangping Trough and the Chengkou-Fengjie-Lichuan-Shizhu area of the Chengkou- E'xi Trough. |
| Keywords: Middle-Upper Permian; Gufeng Formation; 3rd member of Wujiaping Formation; 1st member of Dalong For⁃
mation; reservoir characteristics; shale gas; northeastern Sichuan Bain |
|
投稿时间：
2025-07-01 |
|
