Manipulation of surface charges of oil droplets and carbonate rocks to improve oil recovery

Abstract

This work investigates the effect of the surface charges of oil droplets and carbonate rocks in brine and in surfactant solutions on oil production. The influences of the cations in brine and the surfactant types on the zeta-potentials of both oil droplets and carbonate rock particles are studied. It is found that the addition of anionic and cationic surfactants in brine result in both negative or positive zeta-potentials of rock particles and oil droplets respectively, while the zwitterionic surfactant induces a positive charge on rock particles and a negative charge on oil droplets. Micromodels with a CaCO3 nanocrystal layer coated on the flow channels were used in the oil displacement tests. The results show that when the oil-water interfacial tension (IFT) was at 10−1 mN/m, the injection of an anionic surfactant (SDS-R1) solution achieved 21.0% incremental oil recovery, higher than the 12.6% increment by the injection of a zwitterionic surfactant (SB-A2) solution. When the IFT was lowered to 10−3 mM/m, the injection of anionic/non-ionic surfactant SMAN-l1 solution with higher absolute zeta potential value (ζoil + ζrock) of 34 mV has achieved higher incremental oil recovery (39.4%) than the application of an anionic/cationic surfactant SMAC-l1 solution with a lower absolute zeta-potential value of 22 mV (30.6%). This indicates that the same charge of rocks and oil droplets improves the transportation of charged oil/water emulsion in the porous media. This work reveals that the surface charge in surfactant flooding plays an important role in addition to the oil/water interfacial tension reduction and the rock wettability alteration.

Fabrication and Evaluation of Quercetin Nanoemulsion: A Delivery System with Improved Bioavailability and Therapeutic Efficacy in Diabetes Mellitus

“…The negative zeta potential could be attributed to the dissociation of fatty acid adsorbed or the presence of negatively charged ions at the interface. In the present study, the negative zeta potential could be due to the hydroxyl group in the quercetin and ethyl oleate that were employed [41,42].…”

Droplet Shape and Drag Coefficients in Non‐Newtonian Fluids: A Review

“…Most of the research models of droplet movement behavior are established on the assumption that the fluid domain is unbounded, and researchers ignore the wall effect when the droplet diameter to container diameter ratio c is less than 0.12. However, in most practical industrial processes, droplet movement is limited by the wall surface, such as oil droplet harvesting in porous rock [93], microfluidic field [94], etc. The influence of the wall surface on droplet shape changes and drag force increases, which eventually reduces droplet terminal velocity.…”

Wettability Alteration Mechanisms in Enhanced Oil Recovery with Surfactants and Nanofluids: A Review with Microfluidic Applications

“…Based on extensive research exploitation on surfactant-assisted EOR, three major phenomena have been commonly identified as wettability alteration mechanisms by surfactants, namely the ion pairing, adsorption, and micellar formation. In general, carbonate reservoirs are mostly composed of calcite, anhydrite, and dolomite, with a positively charged surface [91]. On the other hand, sandstone reservoirs are composed of quartz and feldspar, which makes their surface negatively charged.…”