Foam Performance Under Reservoir Conditions

Abstract

Foams that effectively reduce gas permeability were formed over a wide range of experimental conditions. The ability of selected foaming agents to form foam was evaluated in bulk foam measurements, screening core tests, and in reservoir condition core tests. Results reported show that oil usually adversely affected foam performance with higher molecular weight alkanes showing less of an adverse effect for the foaming agents tested. Foam can be effectively generated in an oil-wet porous medium but was shown to be much less effective than in a water-wet medium for the foaming agents studied. High pressure gradients of up to 4524 kPa/m (200 psi/ft) resulted in effective foam generation with an effective foam continuing to 8500 pore volumes of injected nitrogen. The enriched gas mixture used in this study was shown to adversely affect foam even though the foaming agent was selected through screening testing. This showed the importance of including reservoir condition testing prior to the final selection of a foaming agent for a given reservoir application. Effective foaming agents were identified for use in pilot tests in a typical West Texas CO2 flood and in a typical Canadian hydrocarbon miscible flood.

Properties of N2- and CO2-foams as a function of pressure

“…Foam is generally thought to be more efficient (i.e., easier to form and more stable) in waterwet rocks than in mixed/oil-wet porous media (Farajzadeh, et al, 2012b;Rossen, 1996;Schramm et al, 1994Schramm et al, , 1996Suffridge et al, 1989). Though, findings supporting good CO 2foam performance in oil-wet medium have also been reported (Haugen et al, 2014Lescure and Claridge, 1986;Rafati and Hamidi, 2011;Romero-Zeron and Kantzas, 2007).…”

Effects of compositional variations on CO2foam under miscible conditions

“…In the high‐pressure floods, the dense state of the gas acts more like a liquid than like the gas but it does not cause any difficulty in the formation of the foam . Suffridge et al and Mannhardt et al also showed the possibility of foam formation in porous media with hydrocarbon gas under miscible conditions. It should be noted that “foams” are mainly referred to the dispersion of the gas in a liquid phase; whereas, the dispersions of a dense, liquid‐like state of the gas phase or solvent in an aqueous phase might more appropriately be called emulsions .…”

Core-scale sensitivity study of CO2 foam injection strategies for mobility control, enhanced oil recovery, and CO2 storage

“…Foam stability can be reduced with decreasing carbon content in crude oils. It has also been observed elsewhere that a lower number alkanes are more destabilizing than higher number alkanes, because their shorter hydrocarbon chains are more easily imbibed into foam plateau borders to solubilize with surfactants leading to oil spreading and foam instability [10,[37][38][39].…”