Surfactant loss during chemical enhanced oil recovery (EOR) is a significant challenge. Slow-release technology offers a potential solution by enabling the sustained and controlled release of surfactants. In this study, we synthesized a nanocomposite, mesoporous silica functionalized with thermosensitive poly N-vinyl caprolactam (PNVCL), as a carrier for cetyltrimethylammonium bromide (CTAB). The performance of this nanocomposite carrier (NC carrier) in EOR mechanisms was evaluated, including its ability to reduce interfacial tension (IFT), alter wettability, inhibit surfactant adsorption on carbonate and sandstone rock powders, and improve emulsification. The NC carrier provided a gradual release of CTAB and significantly reduced IFT and contact angle, with a 250 ppm NC carrier solution in formation brine (FW) lowering the IFT to 0.31 ± 0.04 mN/m and the contact angle to 48.75°. The NC carrier also significantly decreased CTAB adsorption, achieving around 70 % reduction in adsorption density at 2000 ppm, with the adsorption isotherm transitioning from Freundlich to Langmuir. Moreover, the NC carrier exhibited high emulsification performance with a minimal aggregation, maintaining a nearly constant O/W droplet size in the range of 1.31–1.68 µm over a two-month period. The considerable performance of the smart NC carrier for EOR under the harsh conditions of FW highlights its potential to overcome surfactant flooding limitations.

 

 https://www.sciencedirect.com/science/article/abs/pii/S0927775725014530