Wettability alteration during foam flooding in an oil-wet glass bead pack by using a surfactant-silicon dioxide nanofluid.

Abstract

The stability of foam inside porous media is sensitive to the rock’s wettability where it is stable in a water-wet system, however, has a detrimental effect in an oil-wet system. Hence, this study utilized hydrophilic silicon dioxide (SiO2) and partially hydrophobic silicon dioxide (PH SiO2) nanoparticles in the presence of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactant while altering the oil-wet glass bead pack during foam flooding. The increase of foam apparent viscosity and mobility reduction factor (MRF) indicate the increase of the water-wetness. In the static test, we observed that both surfactant-nanoparticles systems successfully altered the carbonate rock from an oil-wet to water-wet, and improved half-life foam stability. However, the type of surfactant and nanoparticles that produced the lowest contact angle during the wettability alteration static test was an inverse sequence to the oil displacement during the foam flooding dynamic test. Three mechanisms that contributed to oil displacement in the oil-wet glass bead pack were foam stabilization, wettability alteration, and oil-water interfacial tension (IFT) reduction. Since foam stabilization and wettability alteration are crucial in an oil-wet system for foam flooding, supposedly, the silicon dioxide nanoparticles will be utilized in current foam-enhanced oil recovery (EOR) worldwide, especially in the carbonate reservoirs.