Pore-scale description of surfactant-enhanced waterflooding for heavy oil recovery

This study provides new insights into some pore-scale displacement events occurring in the presence of adverse mobility ratio through mixed-wet porous media with different pore throat sizes. This type of flow is normally created in surfactant-based chemical flooding of heavy oil reservoirs. The experiments were carried out in three etched micromodel networks (each with a different pore throat size) containing oleic phase, aqueous surfactant solution, and connate water film. We discussed the first part of the pore-scale mechanisms and events, which were observed in the micromodel experiments, in Yadali Jamaloei and Kharrat (2011). Here we present the second part of our analysis of the pore-scale displacement events and the interactions between oleic phase, aqueous surfactant solution, and connate water film in pore networks with different pore throat sizes. Furthermore, some implications for the pore-scale network modeling of this type of flow are discussed. Finally, the effects of pore throat size on the distribution of the pore-scale capillary number and the mean pore-scale Weber number are evaluated.

► New details of pore-scale events in surfactant flooding of heavy oil reservoirs.
► Each micromodel with a different throat size contains oil, surfactant and brine.
► Pore-scale interactions between oil, surfactant and connate water film are cited.
► Implications for pore-scale network modeling of surfactant flooding are discussed.
► Impact of throat size on pore-scale capillary number and Weber number is examined.