Nanofluids Development to Improve Oil Recovery: A Synergistic Effect Investigation

Abstract

Various type of nanoparticles has been studied in last decade for improve oil recovery purpose and observed its mechanisms of displacing oil concluded as disjoining pressure that involved wettability alteration, log-jamming, and viscosity effect. This paper focus on the investigation of new potential mechanism of nanoparticles to improve oil recovery with study case in an offshore Malaysian oilfield. The silica-based nanoparticles were used in this study, and additives of polymer and surfactant were involved to improve stability of fluid and observe any potential of novel mechanism. The nanoparticles were characterized under electron microscope, dispersed, and sonicated in saline water as replicated of injected water to be nanofluids for particular concentrations. A degassed crude oil from Malaysian field was used with viscosity of 3 cP. All fluids measured their rheology and fluid properties. A polymer additive was used to improve particles stability dispersed in saline water. Meanwhile, a surfactant additive was added into the formulation to observe any synergetic effect of displacing oil. The interfacial tension (IFT), optical contact angle (OCA), and relative permeability measurement using native cores at reservoir condition to observe potential novel mechanism. The additive showed better performance in term of stability and wettability alteration through IFT reduction and reducing contact angle to render more water-wet through dynamic OCA measurement. The synergistic effect was observed when surfactant added into the nanofluids, and classified as fragmentation. The IFT reduced significantly when nanofluids contact with crude oil from field after 10-20 minutes and oil drop started disintegration. This phenomenon was identified consistently through OCA measurement. It altered surface of rock from medium water-wet to strong water-wet. The relative permeability measurement showed consistent wettability alteration that the curve shifted from water-wet to be stronger water-wet. This observation not only showcases the great potential of nanoparticles but also providing a new reference for synthesizing and formulating nanoparticles as a technique to improve oil recovery.