Experimental investigation of water sensitivity effects on microscale mechanical behavior of shale

Clay enrichment experiments were carried out with the Chinese national standards “SYT 5163-2010” to semi-quantitative study of each type of clay mineral in samples. Contact resonance (CR) technique was performed to characterize micromechanics of shale after exposure to water. A total of 64 plus A16 test areas in samples of terrestrial shale in the Ordos Basin and of marine shale in the Sichuan Basin were selected for testing. The results indicated that the compositions of the terrestrial and marine shales were significantly different. Moreover, strength-related mechanical properties, such as storage modulus, of shale would decrease after shale interacts with water, but with different contributions from brittle minerals and clay, as well as variations depending on bedding plane orientation.