Organic-rich mudrocks have complex mineralogy and can be a mixture of inorganic minerals such as quartz, pyrite, calcite, clays and organic matter such as kerogen, bitumen, and pyrobitumen. The volumetric concentration of kerogen in the rock could be up to 30% or even higher . Thus, it is an important constituent of organic-rich mudrocks, and can significantly affect their rock physics and fluid-flow properties. Pores hosted by organic matter comprise the dominant or subsidiary pore network of many shale-gas and shale-oil systems (Loucks and Reed, 2014). Secondary porosity is formed in kerogen as it becomes thermally mature (Loucks et al, 2009; Milliken et al, 2013; Löhr et al, 2015), which causes an increase in surface to volume ratio of kerogen. Therefore, surface properties of kerogen including wettability could significantly impact wettability of organic-rich mudrocks and multiphase fluid flow in these complex formations.