A modified true triaxial apparatus for measuring mechanical properties of sandstone coupled with CO2-H2O biphase fluid
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- 作者：Shaobin Hu ; Xiaochun Li ; Bing Bai ; Lu Shi ; Mingze Liu and Haiqing Wu
- 刊名：Greenhouse Gases: Science and Technology
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：7
- 期：1
- 页码：78-91
- 全文大小：1090K
- ISSN：2152-3878
文摘
Mechanical behaviors of rock under biphase or multiphase fluids conditions are key scientific issues currently in geomechanics and geotectonics. In this work, we conducted a series of triaxial experiments using a semipermeable separator method to form a specific composition pressure; we comparatively investigated the mechanical behaviors of sandstone in the conditions of monophase fluids CO2/N2/H2O and biphase fluid CO2-H2O; and we analyzed the strength, elasticity modulus and brittleness of sandstones at different porous fluid conditions. The results showed that the selective adsorption of mineral compositions of sandstone on CO2/N2/H2O has obvious effects on mechanical behaviors. The linear elastic modulus of CO2-H2O coupled sandstone was slightly greater than that of H2O-bearing sandstone, but significantly less than that of CO2- or N2-bearing sandstone. Compared to H2O, CO2 or N2 containing sandstones are mainly subjected to the brittle failure and exhibit no obvious plastic deformation. Overall, the study analyzed the mechanisms of physicochemical interactions of fluid with sandstone minerals from the micro-scales, and revealed the mechanical mechanism between fluids and mineral particles, and established a new effective stress model of sandstone under CO2-H2O biphase condition.