Page 263 - Enhanced Oil Recovery in Shale and Tight Reservoirs

EOR mechanisms of wettability alteration and its comparison with IFT 245

Figure 9.25 Contact angle changes with time for anionic surfactants AOS and AES.

depends on the rock type. Chen and Mohanty (2014) reported Adibhatla
and Mohanty’s (2008) work that the tested carbonate rock wettability was
not altered by either property alpha olefin sulfonate (AOS) or alkyl aryl sul-
fonate in softened brine, although such data are not found in the original
Adibhatla and Mohanty (2008) paper.
Nonionic surfactants have excellent solubility, high chemical stability,
and high tolerance to hard brine, but their cloud points are low. Chen