Stabilizing CO2 Foam by Use of Nanoparticles

Abstract

Summary Foamed fluids have been used for decades to diminish formation damage in nearly all kinds of reservoirs over a wide range of pressures and temperatures. Although water-based fluids are widely used in the oil industry as one of the most-economic hydraulic-fracturing methods, foam is another viable alternative to fracture water-sensitive reservoirs where damage to pore throats is caused by swelling clays or fines migration. CO2 foam not only reduces formation damage by minimizing the quantity of aqueous fluid that enters the formation, but also significantly improves sweep efficiency. Even though surfactant is commonly used to generate stable foam in high-temperature and high-salinity environments, such foam can degrade in these harsh conditions. The main objective of this study is to improve the stability of CO2 foam by the use of a mixture of CO2/alpha olefin sulfonate (AOS) solution with nanoparticles, guar gum, or viscoelastic surfactants (VESs). Foam stability is studied for various solutions by the use of a high-pressure view-chamber (HPVC) setup to find the optimal surfactant and nanoparticle concentration at which higher foam stability in the CO2 foam system can be reached. In addition to surfactant and nanoparticle concentration, the effects of temperature, pressure, and salinity on foam stability were studied. Temperature ranged from 75 to 212°F, and pressure increased from atmospheric to 800 psi. AOS solutions were prepared with brine and surfactant concentrations ranging from 1.0 to 10 wt% of NaCl and zero to 1 wt% of AOS. Temperature and pressure had a negative effect on the foam stability when AOS solutions were used. However, nanoparticles improved the foam stability for AOS, AOS and guar gum, and AOS with VES solutions.

CO2 Foam for Enhanced Oil Recovery Applications

“…In addition to silica, other types of nanoparticles can also be used to improve foam stability. About 0.1 wt% Fe 2 O 3 nanoparticles were able to increase the AOS foam half-life time from 1 to 7 h at 75 ° F and 300 psi [37]. However, these nanoparticles tend to aggregate due to their large surface area, which is confirmed by low absolute zeta potential values.…”

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

“…The increase in nanoparticle concentration (0-5 wt.%) increased the mobility reduction factor from 4000 to 8700 and increased foam stability. It has also been experimentally proven that the presence of nanoparticle creates better foam stability than surfactant or VES fluids and even polymer, and improves mobility control; and efficient for enhancing oil recovery owing to high sweep efficiency and effective viscosity [137][138][139][140][141][142] (Table 2). • Particle size influences porous media retention and transport behavior; SiO 2 with small particle size promote efficient penetration through the porous media…”

Insights into CO2 Foaming Behavior of Ethoxylated Amines

“…In high-salinity environments, the process of foam coalescence starts earlier, and foam collapses at a faster rate. Several authors have investigated the use of alpha-olefin sulfonate (AOS) with additives such as SiO 2 nanoparticles and cocamidopropyl betaine (cocobetaine) viscoelastic surfactant for CO 2 EOR application but only for solutions with salinity up to 8 wt% NaCl [10,11]. These researchers further identified an insolubility threshold at salinity greater than 8 wt%.…”