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ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Economic Geology
Volume 13 - 2025 | doi: 10.3389/feart.2025.1524678
This article is part of the Research Topic Formation Mechanism and Heterogeneity Evaluation of Lacustrine Shale Reservoirs View all 5 articles
Pore characteristics of clay minerals in the Qingshankou Shale,Songliao Basin,China: unravelling the the effects of illitization
Provisionally accepted- Research Institute of Petroleum Exploration and Development (RIPED), Beijing, China
Clay minerals are key components of lacustrine shale. The transformation of clay minerals, particularly illitization, plays a crucial role in reservior quality. However, this process has yet to be fully understood. In this study, the Cretaceous Qingshankou Shale(QSK shale) samples were cored from the Gulong Sag,Songliao Basin to analyze the pore characteristics of clay minerals and the illitization process using FE-SEM, Qemscan, XRD, and nitrogen adsorption. The main findings are: ① Clay minerals in the QSK shale are mainly illite and illite/smectite mixed layers, with an average content of over 40%. Intensive illitization resulted in a high(>60%)illite content in clay minerals; ② Pores in clay minerals are the main storage spaces in the QSK shale. Illite and illite/smectite mixed layers mainly develop micropores and mesopores with an equivalent pore size of less than 50nm. Chlorite develops macropores with an equivalent pore size of 50-100nm as well as narrow and long pores larger than 800nm; microcracks are important for connecting clay mineral pores; ③ The QSK shale has undergone illitizations of illite/smectite mixed layer and albite, with the illitization of illite/smectite mixed layer as the main process. The clay mineral porosity increases with the illite content up to 30% due to illitization, which improves the overall reservoir property. Further illitization, however, reduces the porosity.
Keywords: Clay Minerals, Illitization, Gulong shale, Pore characteristics, reservoir performance 0 Introduction
Received: 08 Nov 2024; Accepted: 07 Mar 2025.
Copyright: © 2025 Jiang, Zhu, Wu, Zhang, Yu, Guan and Ding. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Xiaohua Jiang, Research Institute of Petroleum Exploration and Development (RIPED), Beijing, China
Rukai Zhu, Research Institute of Petroleum Exploration and Development (RIPED), Beijing, China
Songtao Wu, Research Institute of Petroleum Exploration and Development (RIPED), Beijing, China
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