Experimental study on mechanical properties of granite after reaction with supercritical carbon dioxide at high temperature and high pressure

Authors

Hui XUE, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, China
Biao SHU, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, ChinaFollow
Jun-jie CHEN, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, China
Wei LU, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, China
Yong-peng HU, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, China
Yi-min WANG, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, China
Fan ZENG, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, China
Ruo-chen HUANG, School of Geosciences and Info-physics, Central South University, Changsha, Hunan 410083, China

Abstract

In order to study the effect of supercritical carbon dioxide (ScCO2) on the mechanical properties of granite located in and near the core of the CO2-based enhanced geothermal system (EGS) region, fluid–rock interaction experiments were conducted at 210, 240 and 270 ℃. Three test conditions were used: (1) ScCO2 and dry granite; (2) ScCO2, water vapor and granite; and (3) ScCO2 and granite soaked in water for 24 h. The P-wave velocity, uniaxial compressive strength (UCS), and Young’s modulus of all ScCO2- treated granite samples and one untreated granite sample were obtained by carrying out the wave velocity tests and uniaxial compression tests. The wave velocity tests showed that the P-wave velocities of all ScCO2-treated granite samples were reduced compared to that of the untreated sample. The uniaxial compression test showed that the UCS and Young’s modulus were almost not affected. From the failure mode, it can be seen that the untreated granite more likely presented the brittle tensile failure, while the treated sample showed more likely shear failure. As the temperature increased, the failure mode became more and more close to shear failure. Experimental results showed that the ScCO2 induced slight damage to the granite under dry or a little water condition, causing a slight decrease in the brittleness, and a small increase in the plasticity. The P-wave velocity decreased slightly and the impact on the granite strength can be negligible. Therefore, the interaction of CO2–rock will not cause obvious effect on the mechanical properties of granite located in and near the core of the CO2–EGS region.

Graphic Abstract

Recommended Citation

XUE, Hui; SHU, Biao; CHEN, Jun-jie; LU, Wei; HU, Yong-peng; WANG, Yi-min; ZENG, Fan; and HUANG, Ruo-chen (2022) "Experimental study on mechanical properties of granite after reaction with supercritical carbon dioxide at high temperature and high pressure," Rock and Soil Mechanics: Vol. 43: Iss. 2, Article 4.
DOI: 10.16285/j.rsm.2021.6165
Available at: https://rocksoilmech.researchcommons.org/journal/vol43/iss2/4