For processes involving gas injection, such as enhanced oil recovery (EORa) and CO2 storage operations, the use of foam makes it easier to control gas mobility. Improving these processes requires thorough knowledge of the foam’s flow properties in porous media.
However, the structure of the confining medium, the pore surface state (wettability), the presence of oil and the composition of the injected gas are all parameters that can influence the stability of the foam and its flow properties. Experimental research is thus required to study these phenomena under various temperature and pressure conditions.
The tests conducted to date have involved the co-injection of brines (containing surfactants) and gases of variable compositions (CO2 and CO2 + CH4, N2). They were carried out in the presence and absence of oil, and in waterwetting or partially oil-wetting porous media. The determination of the role of these parameters and their combined Foam rheology in porous media influences was facilitated by the use of an experimental set-up reducing the experimentation time by 30%.
The results obtained(1, 2) demonstrate, in particular, a significant reduction in foam viscosity in porous media with altered wettability (AW curve on the figure).
Future experiments with transparent porous micromodels, coupled with an in situ foam observation technique, will provide invaluable information for understanding the complex interactions between porous media, injected fluid properties and the flow of the foams formed.
a - Enhanced Oil Recovery.
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