Application of sustainable foaming agents to control the mobility of carbon dioxide in enhanced oil recovery

Carbon dioxide (CO₂) flooding is a conventional process in which the CO₂ is injected into the oil reservoir to increase the quantity of extracting oil. This process also controls the amount of released CO₂ as a greenhouse gas in the atmosphere which is known as CO₂ sequestration process. However, the mobility of the CO₂ inside the hydrocarbon reservoir is higher than the crude oil and always viscous fingering and gravity override problems occur during a CO₂ injection. The most common method to overcome these problems is to trap the gas bubbles in the liquid phase in the form of aqueous foam prior to CO₂ injection. Although, the aqueous foams are not thermodynamically stable, special care should be considered to ensure bulk foam preparation and stability. Selection of a proper foaming agent from a large number of available surfactants is the main step in the bulk foam preparation. To meet this purpose, many chemical and crude oil based surfactants have been reported but most of them are not sustainable and have disposal problems. The objective of this experimental study is to employ Lignosulfonate and Alkyl Polyglucosides (APGs) as two sustainable foaming agents for the bulk foam stability investigations and foam flooding performance in porous media. In the initial part, the bulk foam stability results showed that APGs provided more stable foams in comparison with Lignosulfonate in all surfactant concentrations. In the second part, the results indicated that the bulk foam stability measurements provide a good indication of foam mobility in porous media. The foaming agent’s concentration which provided the maximum foam stability also gave the highest value of mobility reduction in porous media.