Microvisual Observation of Foam Generation and Coalescence Using Micromodels in the Presence and Absence of Oil
Advisor
Anthony R. Kovscek
Abstract
The stability of foam in porous media is extremely important for realizing the advantages of foam injection on gas mobility reduction. The foam texture (i.e., bubbles per volume of gas) achieved is dictated by the foam generation and coalescence processes occurring at the pore level. For foam injection to be widely applied in gas injection projects, we need to understand these pore-scale events that lead to foam stability/instability and be able to model them predictably. Foam flow has been studied for decades but most studies focused on studying foam in the absence of oil. We review the extensive existing literature to identify open questions. Then, we use etched silicon micromodels to study both foam generation and coalescence processes with an emphasis on foam coalescence in the presence of oil. The foam-oil interactions that were observed include: emulsification, lamella pinch-off, hindered foam generation and reduced trapped gas saturation. Some of these mechanisms were implemented in the population balance model by other researchers but never observed while other mechanisms provide direction towards better foam modeling.