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Geofluids
Volume 2017, Article ID 8354524, 15 pages
https://doi.org/10.1155/2017/8354524
Research Article

Experimental Study on the Effects of Stress Variations on the Permeability of Feldspar-Quartz Sandstone

1Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130012, China
2Center for Hydrogeology and Environmental Geology Survey, China Geological Survey, Baoding 071000, China
3Key Laboratory of Carbon Dioxide Geological Storage, Center for Hydrogeology and Environmental Geology Survey, China Geological Survey, Baoding 071000, China

Correspondence should be addressed to Fugang Wang; nc.ude.ulj@gnagufgnaw

Received 20 February 2017; Revised 24 June 2017; Accepted 9 August 2017; Published 10 September 2017

Academic Editor: Kundan Kumar

Copyright © 2017 Fugang Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The multistage and discontinuous nature of the injection process used in the geological storage of CO2 causes reservoirs to experience repeated loading and unloading. The reservoir permeability changes caused by this phenomenon directly impact the CO2 injection process and the process of CO2 migration in the reservoirs. Through laboratory experiments, variations in the permeability of sandstone in the Liujiagou formation of the Ordos CO2 capture and storage (CCS) demonstration project were analyzed using cyclic variations in injection pressure and confining pressure and multistage loading and unloading. The variation in the micropore structure and its influence on the permeability were analyzed based on micropore structure tests. In addition, the effects of multiple stress changes on the permeability of the same type of rock with different clay minerals content were also analyzed. More attention should be devoted to the influence of pressure variations on permeability in evaluations of storage potential and studies of CO2 migration in reservoirs in CCS engineering.