Macroscopic seepage and microstructural behavior of oil shale using water vapor injection during mining

Lei Wang; Ziqi Wang; Yangsheng Zhao; Runxu Zhang; Dong Yang; Zhiqin Kang; Jing Zhao

doi:10.1016/j.jrmge.2024.10.024

Journal of Rock Mechanics and Geotechnical Engineering (Mar 2025)

Macroscopic seepage and microstructural behavior of oil shale using water vapor injection during mining

Lei Wang,
Ziqi Wang,
Yangsheng Zhao,
Runxu Zhang,
Dong Yang,
Zhiqin Kang,
Jing Zhao

Affiliations

Lei Wang: Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China; State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources, China University of Mining and Technology, Xuzhou, 221116, China; Jinneng Holding Equipment Manufacturing Group, Jinneng Holding, Jincheng, 048006, China; The In-situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation, Taiyuan University of Technology, Taiyuan, 030024, China; Corresponding author. Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China.
Ziqi Wang: Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China; The In-situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation, Taiyuan University of Technology, Taiyuan, 030024, China
Yangsheng Zhao: Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China; The In-situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation, Taiyuan University of Technology, Taiyuan, 030024, China
Runxu Zhang: Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China; School of Safety and Emergency Management Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
Dong Yang: Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China; The In-situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation, Taiyuan University of Technology, Taiyuan, 030024, China
Zhiqin Kang: Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China; The In-situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation, Taiyuan University of Technology, Taiyuan, 030024, China
Jing Zhao: Key Laboratory of In-situ Property Improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, 030024, China; The In-situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation, Taiyuan University of Technology, Taiyuan, 030024, China

DOI: https://doi.org/10.1016/j.jrmge.2024.10.024
Journal volume & issue: Vol. 17, no. 3
pp. 1489 – 1509

Abstract

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In the context of convection-heating-based in situ oil shale retorting, fractures serve as primary pathways for fluid migration and product extraction. This study investigates the permeability and microstructural evolution of oil shale during water vapor injection in single-fracture and no-fracture scenarios. Three types of oil shale are investigated: intact oil shale, oil shale with a single straight crack, and oil shale with a single hydraulic crack. With increasing water vapor temperature, the permeabilities of the intact oil shale and oil shale with a fractured crack exhibit a trend of initial increase, followed by a decrease, and then a subsequent increase. However, the permeability of oil shale with a single straight crack consistently increases and exceeds that of oil shale with a fractured crack. The temperature-dependent permeability changes in fractured oil shale – a slight decrease in fracture cracks and a gradual increase in straight cracks – mainly occur in the range of 300 °C-350 °C. The permeability of oil shale with a straight crack is approximately three times that of oil shale with a fractured crack. This is attributed to the retention of viscous asphaltene and the frictional resistance caused by the rough fracture structure. For the oil shale with a single crack, the crack permeability has a dominant influence on the overall permeability of the rock. The contribution of the permeability of the straight crack exceeds 94.6%, while that of the permeability of the fractured crack is greater than 86.1%. The disparity in the contribution of these two crack structures is evident at 350 °C-550 °C.

Published in Journal of Rock Mechanics and Geotechnical Engineering

ISSN: 1674-7755 (Print)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Engineering (General). Civil engineering (General): Engineering geology. Rock mechanics. Soil mechanics. Underground construction
Website: https://www.sciencedirect.com/journal/journal-of-rock-mechanics-and-geotechnical-engineering

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