A Mechanism Study of Wettability and Interfacial Tension for EOR Using Silica Nanoparticles

Abstract

Wettability alteration and interfacial tension (IFT) reduction are two important mechanisms for enhanced oil recovery (EOR). The introduction of nanotechnology from the fields of Biology and Material Science to the application in EOR is emerging because nanoparticles have the potential to alter formation factors like wettability and fluid properties like IFT and viscosity. However, a systematic literature review shows that ambiguity exists regarding whether nanoparticles can change wettability and IFT or not and which component in nanofluid plays a role. In this work, we investigated the effects of bare silica nanoparticles on wettability and IFT using a contact angle goniometer. The results showed that the contact angle measurement on quartz plates had relatively large uncertainty while those on calcite plates showed a clear trend that the smaller the nanoparticle size and the larger the nanofluid concentration, the smaller the contact angle. In addition, silica nanoparticles did not have an effect on IFT. Core flooding experiments showed an increase of 8.7% in oil recovery factor by the use of silica nanoparticles, which support the oil recovery mechanism of wettability alteration.

The effect of nanoparticles on reservoir wettability alteration: a critical review

“…The movement behaviour of nanoparticles in porous media has been investigated widely, focusing on the flow, rheological behaviour and adsorption of the nanoparticles on rocks. Oil displacement mechanisms by new nanoparticles are still not explained enough and need more investigation (Agi et al 2018); however, the EOR mechanisms of nanofluids are summarised as follows: disjoining pressure, pore channel plugging, increasing the viscosity of injection fluids, IFT reduction, wettability alteration, and preventing asphaltene precipitation (Jiang et al 2017;Ortega et al 2016;Tarek 2015). Figure 1 presents a schematic of the most common nanofluid EOR mechanisms.…”

“…Disjoining pressure is defined as the pressure required for removing fluids which are in contact with the reservoir rocks due to the adhesion force of fluids/solid surface (Jiang et al 2017). Theoretical and experimental investigations show that the nanofluids reduce oil adsorption on a rock surface by entering a structural disjoining force (film) between the oil and the rock surface and then creating a wedge film structure on the rock surface.…”

The Impact of Nanoparticle Adsorption on Transport and Wettability Alteration in Water-Wet Berea Sandstone: An Experimental Study

“…The ability of nanoparticles to alter the wettability has been extensively studied. Contact angle measurements show that different types of nanoparticle (silicon dioxide, iron oxide, aluminum oxide and titanium dioxide) can reduce contact angle between oil and water, making surface more water wet regardless of initial surface wettability [13][14][15][16]. Microfluidic flooding experiments show that nanofluid flooding can alter wettability of glass grains.…”

Review on enhanced oil recovery by nanofluids

“…In order to avoid the above problems caused by the addition of surfactants into nanofluids, Jiang et al (2017) investigated the effect of nanoparticles addition on the wettability and oil recovery without adding any other chemicals other than silica nanoparticles into the nanofluid. They found that bare silica nanoparticles had an impact on wettability.…”

“…An increase in nanofluid concentration and a decrease in nanoparticle size both result in a decrease in contact angle (makes the substrate more water-wet), which increase the oil recovery by about 8.7%. Jiang et al (2017) reported that bare silica nanoparticles had no influence on IFT between n-decane and nanofluid.…”