Pore Level Displacement Mechanisms During Foam Flooding

ABSTRACT

The foam-drive process has been considered in the oil and gas industry as an enhanced oil recovery method. However, practical application of this process is rather restricted. The main limitation of foam field application is the complexity of its flow behavior in porous media. Nevertheless, the key advantage of foam over any gas drive process is that foam is less mobile than free gas, decreasing gas mobility and thus increasing oil recovery. In addition, it has been demonstrated that the foam flooding process assures substantial recovery of oil not otherwise recoverable by waterflooding or immiscible gas injection. This paper depicts a pore level visualization study, through visual observation of foam flooding in transparent etched-glass micromodels. In this study the effect of aqueous foam flooding and polymer enhanced foam flooding on residual oil recovery efficiency is evaluated. In addition, the effect of foam texture and porous media morphology on foam flood displacement performance is considered. Photographed and videotaped experimental results provide visual demonstration of high oil recovery efficiency, as a result of foam flooding. Image analysis shows that more than 90% of the residual oil in place can be recovered after waterflooding and gasflooding. Ultimately, visual observations demonstrate that foam flood displacement efficiency increases with porous media connectivity. The visualization experiments are also used to identify the pore level displacement mechanisms.

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