Influence of Surfactants on Hydrocarbon Mobility in Narrow Pores in the Presence of Water

Molecular dynamics simulation has been employed to study the influence of standard surfactants and other additives used in oil production on the mobility of a liquid that occurs in contact with a very thin (comparable with molecular sizes) layer adsorbed on a solid substrate that exhibits affinity for the latter. Both a hydrophilic surface with a thin water layer occurring in contact with decane and a hydrophobic surface with a thin adsorbed decane layer occurring in contact with water were studied. The used surfactants increase the wettability at the water–decane interface, thereby decreasing the mobility of the liquids. At the same time, no correlation has been found with effective volumes of hydrophilic and hydrophobic groups, thus indicating that the limitation of the mobility is not only due to mechanical hindrances created by the low-mobility molecules of the additives. Decane-soluble additives have no significant effect on the mobility.