LAUSR

During the fracking process in shale, an interaction occurs between shale and fracking fluid that contains a cocktail of chemicals. One of the chemicals used in fracking fluid is often surfactant, which is generally used as a viscofier. However, surfactants also have the potential of significantly influencing the wettability and thus gas desorption–key factors affecting ultimate gas recovery from shale reservoirs. Even though a few studies discussed the ability of surfactants to alter wettability in shale, the implication of that change in adsorption/desorption behavior has never been experimentally investigated beyond hypothetical inferences. In this study, the influence of the wettability change by anionic surfactant on gas adsorption/desorption behavior in shale was investigated through a series of experiments. Baseline wettability readings of two shale samples were established by measuring the contact angles (BG-1 = 22.7°, KH-1 = 35°) between a drop of pure water placed on their polished surfaces, ind...