Energy & Fuels, Vol.32, No.7, 7319-7325, 2018
Electrical Double-Layer Expansion Impact on the Oil Quartz Adhesion for High- and Low-Salinity Brines
Expanding the electrical double layer of minerals through low-salinity brine injection has been suggested as a possible enhanced oil recovery mechanism. To investigate this theory, we measured the potential of different minerals, namely, sands from Fontainebleau, Ottawa, and Landes, a sample from a sandstone outcrop, and one crude oil. c-potential measurements can be used to quantify the surface charges of materials; therefore, experiments associated with this technique were performed to predict the behavior of repulsion or attraction between materials in different salinity and pH conditions. We showed that there is no significant difference between the xi potentials of the tested materials. We did, however, observe that the different sands and sandstone have dissimilar adhesion behaviors. No correlation was found between the electrokinetic measurements performed on the minerals and their response to crude oil introduced into the system. The adhesion results obtained for the Landes and Ottawa sands were perfectly in line with what was expected from xi-potential measurements, but the Fontainebleau sand and sandstone exhibited different behaviors. For the tested minerals, we showed that xi-potential changes may not be only responsible for a low-salinity brine effect concerning a system oil/brine/rock systematically characterized in a coreflood with an observed additional recovery.