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.本研究依据中国国家标准《SYT 5163-2010》开展黏土富集实验，以对样品中的各类黏土矿物进行半定量研究。采用接触共振（Contact Resonance, CR）技术，对经水作用后的页岩微观力学特性进行表征。共选取鄂尔多斯盆地陆相页岩样品与四川盆地海相页岩样品中的64个及A16个测试区域进行测试。测试结果表明，陆相页岩与海相页岩的组分存在显著差异。此外，页岩与水作用后，其强度相关力学特性（如储能模量）会出现下降，且脆性矿物与黏土矿物对此的贡献程度各不相同，此类力学特性的变化还会受层理面取向的影响。