Study of the Synergistic Effect of the Nanoparticle-Surfactant-Polymer System on CO₂Foam Apparent Viscosity and Stability at High Pressure and Temperature

Abstract

The goal of this study is to experimentally investigate the stability and rheological behavior of supercritical CO2 foam in the presence of nanosilica, a surfactant, and a polymer. First, three types of surfactants with different charges were used to generate CO2 foam together with nanosilica under supercritical conditions. The anionic, cationic, and nonionic surfactants each interacted differently with the negatively charged silica nanoparticles (NPs). Owing to its yielding the highest apparent viscosity with nanosilica, the anionic sodium dodecyl sulfate (SDS) surfactant was selected to generate nanosilica-stabilized foam with a polymer to further enhance its apparent viscosity. Second, the thermal resistance of nanosilica-SDS-stabilized CO2 foam was assessed in terms of foam apparent viscosity and stability under reservoir conditions with higher temperatures. Finally, supercritical CO2 foams were generated with a combination of nanosilica, SDS, and 2-hydroxyethyl cellulose (HEC) polymer with various concentrations at different temperatures. Results show that the anionic SDS surfactant yielded higher apparent viscosity and foam stability with nanosilica. An optimal SDS concentration was expected, beyond which no significant improvement on foam apparent viscosity could be found judging from the trend of the experiment result. The cationic surfactant dodecyl trimethylammonium bromide (DTAB) and nonionic Ecosurf EH-9 surfactants performed similarly and did not yield any significant improvement in foam apparent viscosity. The addition of the polymer not only yielded higher apparent viscosity but also improved the thermal resistance of the NP-SDS-HEC-stabilized CO2 foam. For each combination of additives, higher temperatures have consistently shown its undermining effect on foam apparent viscosity and stability. However, the combination of the NP-SDS-HEC CO2 foam system has shown great improvement in foam performance compared to the case of foam stabilized with nanosilica alone. The results of this research suggest a compatibility check among additives within the fluid before further optimization work to ensure synergy among these additives. An interactive mechanism among these additives was proposed, which can explain the experimental results consistently. The results of this research can be used as guidance toward the performance optimization of nanosilica-stabilized CO2 foam for fracturing applications.

Stabilization of natural gas foams using different surfactants at high pressure and high temperature conditions

“…In other words, with temperature increasing, the kinetic energy of the surfactant molecules in the solution becomes larger, and the intermolecular force is weak. Secondly, the viscosity of the solution decreases (Fu & Liu, 2020; Kapetas et al, 2016), which leads to the drainage rate increasing, and results in the foam collapsing easily. Thirdly, the evaporation of liquid becomes violent, and the drainage of the liquid phase strengthens.…”

Application of Polymers for Chemical Enhanced Oil Recovery: A Review

“…Nonetheless, the polymer-stabilized foams have better stability in the presence of temperature. Fu and Liu [ 101 ] evaluated the salinity and thermal resistance of CO 2 foam stabilized in the presence of nanoparticles, surfactants, and hydroxylethylcellulose polymers. They noted that the increase in temperature resulted in the decrease of the apparent viscosity of CO 2 foams and accelerated the drainage of the interfacial film.…”

A Review on Foam Stabilizers for Enhanced Oil Recovery

“…Nanoparticles (NPs) range in size from 1 to 100 nm and have intrinsic properties different from those found in the bulk of the material. With the new technological advances in nanoscience, foam stabilized by NPs has been proven to be a promising route to stable CO 2 foam. , Emulsions stabilized by solid particles were first discovered more than a century ago initially by Ramsden and then Pickering. , However, foam stabilization by NPs got attention only in the last decades. A pioneering study in this regard was conducted by Dickson et al, who generated stable CO 2 foam using surface-modified silica NPs .…”

“…With the new technological advances in nanoscience, foam stabilized by NPs has been proven to be a promising route to stable CO 2 foam. 53,54 Emulsions stabilized by solid particles were first discovered more than a century ago initially by Ramsden and then Pickering. 55,56 However, foam stabilization by NPs got attention only in the last decades.…”