Desorption of crude oil components from silica and aluminosilicate surfaces upon exposure to aqueous low salinity and surfactant solutions

Desorption of crude oil components from silica and aluminosilica was investigated by exposing crystal surfaces in a quartz crystal microbalance (QCM) to low salinity water and surfactant solutions. Increasing amounts of aluminum at the crystal surfaces and increasing amounts of polar components (asphaltenes and resins) in the crude oils enhanced the initial adsorption onto the surfaces. This was attributed to polar interactions. Some of the crude oil components desorbed from the surfaces upon exposure to low salinity water, but the desorption became more pronounced when solutions of sodium dodecylbenzene sulfonate (SDBS) were injected. Generally, the extent of desorption decreased with increasing acid number of the crude oils and increasing aluminum content at the surfaces. This could be explained by divalent calcium ions acting as bridges between dissociated silanols at the surfaces and dissociated crude oil components, or by direct attachment of dissociated crude oil components to positively charged sites at the aluminosilica surfaces. Contact angle measurements showed that the surfaces became more water wet as crude oil components desorbed from the surfaces. The results supported that this type of investigations could be well suited to screen important parameters relevant for water based enhanced oil recovery processes.