Investigation on the Stability of Janus SiO_2-n Nanoparticle-Assisted Nonionic Surfactant-Stabilized Foam and Its Application in Enhanced Oil Recovery

摘要

The stability of the foam directly impacts the final efficiency of the foam flooding in enhanced oil recovery (EOR). In the present work, a series of Janus SiO_2-n nanoparticles (JSn NPs) with various modification degrees were successfully prepared and employed to improve the stability of the nonionic surfactant polyethylene glycolmonoisodecylether (PMIE)-stabilized foam. The PMIE-JS3 system with a much low JS3 NP concentration (0.1 wt ) displayed extraordinary foamability and stabilizing foam ability via the foam volume, half-life, relative volume decay, and optical microscope photograph measurements. Then, the dynamic surface tension and dilatational viscoelasticity tests were conducted to explore the mechanism. It was found that the PMIE-JS3 system with great interfacial activity and intensive interfacial film highly facilitated the generation of the foam and improved the foam stability. Moreover, the PMIE-JS3-stabilized foam exhibited outstanding stability, even under the influence of crude oil. The sandpack flooding tests indicated that the PMIE-JS3-stabilized foam could effectively plug the high-permeability channels to modify the water injection profile and consequently greatly enhanced tertiary oil recovery (~15.3 of the initial oil in place).