evaluation of nano-ctab surfactant for the purpose of enhancing oil recovery in an iranian carbonate reservoir

In this research, hexadecyltrimethyl ammonium bromide (ctab) nano-emulsions were prepared at 0#05 and 0#1 wt% and evaluated in comparison with conventional ctab emulsions# particle size analysis showed that average ctab nano-surfactant particle size was approximately 60 nm, much lower than that of the ctab emulsions# zeta potential analysis was used to evaluate the stability of the emulsion and demonstrated that ctab nano-surfactant was more stable than the normal surfactant# ctab nano-surfactant also showed lower interfacial tension with the crude oil sample, in comparison with ctab surfactant# the interfacial tension was more decreased by increasing the surfactant concentration# wettability tests with carbonate rock powder, oil and ctab emulsion/nano-emulsion showed that these surfactants are able to alter the rock wettability toward more water-wet condition# spontaneous imbibition tests were performed at 50 0c on the oil saturated carbonate core samples with brine, surfactant and nano-surfactant, respectively# however, stable emulsions of oil in the aqueous phase made estimating the amount of oil recovery impossible#