A coreflood investigation of nanofluid enhanced oil recovery

Recently nanoparticles have become an attractive agent for improved and enhanced oil recovery (IOR & EOR) at laboratory scale. Most researchers have observed promising results and increased ultimate oil recovery by injecting nanoparticle suspension (nanofluid) in laboratory experiments. The objective of this study is to reveal nanofluid possibility for EOR in low to high-permeability sandstone (ss) rocks and investigate suitable concentration. In this study, parameters involved in the structural disjoining pressure mechanism, such as lowering interfacial tensions (IFT) and altering wettability, were studied. Laboratory coreflood experiments were performed in water-wet Berea ss core plugs with permeability in range 9-400 mD using different concentrations of nanofluids. A crude oil from a field in the North Sea was employed and three nanofluid concentrations 0.01, 0.05 and 0.1 wt% were synthesized with synthetic brine. We observed that IFT decreased when hydrophilic nanoparticles were introduced to brine. The IFT decreases as nanofluid concentration increases and this indicates a potential for EOR. Increasing hydrophilic nanoparticles will also decrease contact angle of aqueous phase and increase water wetness. We have also observed that the higher the concentrations of nanofluids, the more the impairment of porosity and permeability in Berea core plugs. Despite that increasing nanofluid concentration shows decreasing IFT and altering wettability, our results indicate that additional recovery is not guaranteed. The processes and results are outlined and also further detailed in the paper to reveal the possible application of nanofluid EOR as a future or an alternative EOR method. (C) 2013 Elsevier B.V. All rights reserved.