Abstract
This study aims to provide new insights into the interactions among an acidic crude-oil, brine with different salinities and clay using flow experiments in montmorillonite-coated micromodels. To this end, a series of oildisplacement experiments are performed in a transparent clay - coated micromodel. In addition, salinityscreening tests, pH and IFT measurements are performed to support the results of flow-experiments. It is shown that during water injection into a clay-coated micromodel, polar components of crude oil partition between oil/water phases and form an emulsified phase. With the 90% reduction in water salinity, the partitioning of crude oil polar components in the aqueous phase is increased. Such partitioning lead to a significant reduction in the pH of the aqueous phase. This observation is supported by an increase in the IFT of oil/brine due to the decrease of crude oil polar components. Salinity screening tests show that there is a critical water salinity, i.e., below the critical point, a large amount of crude oil polar components is partitioned between phases, which can be attributed to the polarization effect. Overall, results show that low salinity water injection benefits from formation of an emulsified phase and wettability alteration to improve oil recovery in the microscale.
NSTL
Elsevier