Favorable lithofacies and pore characteristics of the Permian Longtan Formation shale in the southern Sichuan Basin  

作　　者：Ya'na Chen Kai Yang Wei Wu Yuran Yang Xue Yang Kai Ma 

机构地区：[1]Hangzhou Geological Research Institute,PetroChina,Hangzhou,Zhejiang,310023,China [2]Earth Exploration and Information Technology Key Laboratory of Ministry of Education,Chengdu University of Technology,Chengdu,Sichuan,610059,China [3]Shale Gas Research Institute of Southwest Oil&Gas Field,PetroChina,Chengdu,Sichuan,610000,China [4]Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan,610059,China

出　　处：《Energy Geoscience》2023年第3期210-219,共10页能源地球科学（英文）

基　　金：supported by the National Natural Science Foundation of China(NNSFC)(Grant No.42272184);2022 Research Program of PetroChina Southwest Oil and Gas Field Company(2022JS-1809).

摘　　要：The marine–continental transitional shale (MCTS) reservoirs of the Longtan Formation (LTF) are widely distributed in the Sichuan Basin. However, the LTF shale exhibits considerable variations in mineral composition and pore characteristics, which makes identifying the 'sweet spot'a challenging task. To address this issue, 10 samples from four typical shale gas wells in the LTF in the southern Sichuan Basin were selected and analyzed for total organic carbon (TOC) content, whole-rock composition using X-ray diffraction (XRD), low-pressure gas adsorption, and high-pressure mercury intrusion. The lithofacies distribution and pore structure of the MCTS were studied to determine the pore structural characteristics and the primary factors influencing pore formation in different types of shale lithofacies in the LTF. The lithofacies of the LTF shale in the study area can be classified into three categories: siliceous clay shale, clay shale and mixed shale. Mineral content has a significant impact on the pore characteristics, while TOC content has a minor effect on the pore volume and specific surface area of micropores and mesopores. It can be inferred that the mesopores in the MCTS are mainly related to clay mineral pores, and mineral dissolution and TOC content are not the primary factors contributing to pore formation.

关 键 词：Pore Characteristics Sweet spot Favor able lithofacies Marine-coninental transitional shale Longtan Fomaion si chuan Basin 

分 类 号：P618.13[天文地球—矿床学]