Synergistic Stabilization of Foams by a Mixture of Nanoparticles and Surfactants

Abstract

The goal of this work is to evaluate stabilization of foams by a combination of nanoparticles and surfactants. Hydrophilic silica nanoparticles (NP) and anionic surfactants were used in this study. Static foams were generated using surfactants and surfactant-NP mixtures with and without the presence of a crude oil. The decay of the foam height with time was studied and half-lives were determined. The foam drainage behavior and thickness of the foam lamella were studied by fluorescence microscopy. Aqueous foams were created in-situ by co-injecting the surfactant or surfactant-NP mixtures with nitrogen gas through a Berea sandstone core at a fixed quality. Pressure drop across the core was measured to estimate the achieved mobility reduction factor (MRF). Oil displacement experiments were conducted in Berea cores using surfactant and surfactant-nanoparticle mixture as foaming agents. Static foam tests indicate stabilization effect of nanoparticles on surfactant-nanoparticle foam stability in the absence of crude oil. Lighter crude oils were more destabilizing to foams than heavier oils. Adding nanoparticles even in low concentrations (0.3 wt %) can significantly improve the foam stability and mobility reduction factor in the absence of oil. As the concentration of nanoparticles increased, mobility reduction factor (MRF) of surfactant-nanoparticle foam in a Berea core increased significantly. Fluorescence microscopy elucidated that nanoparticles are trapped in the plateau border as well as lamellas which retard liquid drainage and bubble coalescence. The core floods with a crude oil revealed that the incremental oil recovery by surfactant-NP blend over water flood was about 10% OOIP with an immiscible foam.

A Realistic Look at Nanostructured Material as an Innovative Approach for Enhanced Oil Recovery Process Upgrading

“…Similarly, Singh and Mohanty [136] reported that nanoparticle-surfactant solutions containing only about 0.3 wt.% nanoparticles significantly modified foam mobility ratio. The increase in nanoparticle concentration (0-5 wt.%) increased the mobility reduction factor from 4000 to 8700 and increased foam stability.…”

Nanoparticle Stabilized Foam in Carbonate and Sandstone Reservoirs

“…Nanoparticles are solid minerals, which are chemically more stable in a reservoir environment. They can show the same foam-generating properties as surfactant molecules, and can be used in synergy with surfactants (Singh and Mohanty 2014).…”

“…The contact angle corresponding to the wettability of a nanoparticle adsorbed at the liquid-gas interface determines the stability of the foam generated by the nanoparticle suspension. A contact angle of 90 degrees provides maximum adsorption energy and therefore the highest stability (Singh and Mohanty 2014, Yu et al 2014, Binks 2002 . In addition, a (partially) hydrophilic particle can bridge the interface of a destabilizing foam lamella, and high concentration of the particles in the liquid phase at the Plateau border slows down the capillary drainage rate (Singh and Mohanty 2014).…”

“…One of the mechanisms nanoparticles enhance foam viscosity in a porous medium, is by reducing the rate at which lamellae drain (Binks 2002, Singh andMohanty 2014). The foam column experiment was used to investigate the effectiveness of the silica-based nanoparticles in reducing bulk foam drainage rate.…”

“…The fact that the increase of viscosity is visible only at higher foam qualities could be related to the thickness of foam films. For 'dry' foams with smaller lamella thickness, the mostly hydrophilic particles are better able to bridge lamella (Singh and Mohanty 2014). Secondly, Plateau borders through which foam drains are smaller for dry foams, which increases the relative resistance by particles inside that border.…”