@article {LIU2019103295,
	title = {Indentation size and loading rate sensitivities on mechanical properties and creep behavior of solid bitumen},
	journal = {International Journal of Coal Geology},
	volume = {216},
	year = {2019},
	pages = {103295},
	abstract = {Creep behavior of rocks could impair fracture conductivity and wellbore stability during gas production from highly matured organic-rich shales in South China, of which the organic matter is mainly in the form as solid bitumen and is thought to be a major contributor for the creep deformation. To get a better insight into this phenomenon, this paper for the first time characterizes the mechanical properties and creep behavior of a millimeter-sized solid bitumen sample by using quasi-static state creep tests and Dynamic Mechanical Analysis in nanoindentation, and reports their dependences on indentation size and loading rate, respectively. Mechanical properties (including hardness and Young\&$\#$039;s modulus) are found to be negatively related with both indentation size and loading rate. The extremely small creep strain rate sensitivity (m) of solid bitumen indicates a localized shear flow inside. And m exhibits slightly positive dependences on indentation size and loading rate. The potential mechanisms controlling the deformation of solid bitumen under indentation are also discussed.},
	keywords = {Creep, Mechanical properties, Nanoindentation, Solid bitumen},
	issn = {0166-5162},
	doi = {https://doi.org/10.1016/j.coal.2019.103295},
	url = {https://www.sciencedirect.com/science/article/pii/S0166516219304100},
	author = {Yuke Liu and Yongqiang Xiong and Kouqi Liu and Chao Yang and Pingan Peng}
}
