Ultrastable N₂/Water Foams Stabilized by Dilute Nanoparticles and a Surfactant at High Salinity and High Pressure

Abstract

The rapid development of unconventional oil and gas resources presents challenges for foam flooding for reservoirs with high salinity and high heterogeneity at elevated temperatures. In this study, hydrophilic anionic sulfonate-modified nanoparticles (NPs) exhibited a synergistic effect with a cationic surfactant in stabilizing N 2 /water foam in the presence of concentrated divalent ions from ambient temperature up to 70 °C. With low concentrations of both the sulfonated NPs (SNPs) and cationic surfactant, the foams remained stable for 4 days at 50 °C and atmospheric pressure, while the surfactant-stabilized foams collapsed completely in 1 day. This stability mechanism of foams by the SNPs and cationic surfactant is described in terms of phase behavior, bulk shear rheology of the aqueous phase, and the dilational modulus of the gas−brine interface. The high surface elastic dilational modulus E′ observed upon addition of the SNP provided stability against coarsening according to the Gibbs criteria. The cryo-SEM images also showed the compact bubble structure of foams provided by the SNPs. Consequently, very minor changes in the foam bubble size were observed at 208 bar (3000 psi) and 50 °C for up to 48 h with only 0.1 wt % or 0.3 wt % SNPs and 0.01 wt % Arquad 12−50, indicating excellent foam stability. The ability of the surfactant and NPs to stabilize foams at low concentrations broadens the application of foams in subsurface reservoirs at high temperatures and salinities.

Stable CO2/water foam stabilized by dilute surface‐modified nanoparticles and cationic surfactant at high temperature and salinity

“…Long‐term foam stability was measured by the same method as past studies (Adkins et al, 2010; Alzobaidi, Da, et al, 2021; Chen et al, 2023; Da et al, 2022; Zhu et al, 2022). Once isolated in the view cell, foam was observed over time with a Nikon microscope camera.…”

“…There has been extensive research in recent years on developing stable foams. “Ultra‐stable” foams—with coarsening rates of about 100 μm 3 /min—have been designed with N 2 (Da et al, 2022; Singh & Mohanty, 2015; Zhu et al, 2022). Unfortunately, differences in chemistry and solubility make N 2 results difficult to translate to CO 2 foams.…”

Review on Oil Displacement Technologies of Enhanced Oil Recovery: State-of-the-Art and Outlook

“…In recent years, the combination of multiple displacement technologies to increase recovery has been evaluated and proven more effective. For example, water alternating gas (WAG) flooding, − nanoparticle/nanofluid-assisted water alternating gas (NWAG) flooding, − NPs and polymers synergistic combination, − NPs assisting foam flooding, − NPs assisting surfactant flooding, − surfactant alternating gas (SAG) flooding, ,, alkaline surfactant alternated gas (ASAG) flooding, − etc.…”

Interfacial rheology insights: particle texture and Pickering foam stability

“…Interfacial rheology can thus be employed in characterizing the ability of an interface to resist distortion and deformation, key factors when attempting to control the thin film drainage and retard or arrest bubble coarsening in foams [76,77]. For instance, Zhu et al [78] studied the dilational rheological properties of interfaces in presence of hydrophilic anionic sulfonate-modified nanoparticles (28.5 ± 0.2 nm) in tandem with the cationic surfactant Arquad 12-50 using pendant drop tensiometry. It was shown that while the surfactant-laden gas-liquid interface exhibited a negligible storage dilatational modulus κ s ′ ∼ 0-10 mN m −1 , for surfactant concentration of 0.01-0.1 wt.%, the addition of 0.1 wt.% particles to the droplet containing 0.01 wt.% surfactant led to an enhancement in the modulus, κ s ′ ∼ 20 mN m −1 .…”