Experiments and Simulations to Study Transport and Structure of Foam in Rough Carbonate Fractures

In this paper, we explore the influence of fracture roughness on foam transport and structure. Foam flow is studied using core flood experiments and novel Lattice Boltzmann method simulations for application in fractured porous media. From experiments, it was observed that a fracture with a rough surface decreased the tendency of lamella collapse and increased apparent viscosity in comparison to the saw-cut smooth fracture. In the temperature range of 40 °Cto 60 ℃, foam structure was more stable at lower ends of this temperature range. Using Lattice Boltzmann method simulations, we applied an existing foam algorithm in 2D fracture geometries and qualitatively assessed foam structure in both smooth and rough fracture geometries. We observed that the foam bubbles in the smooth fracture were smaller and more uniform, like a bulk foam. The bubbles in the rough fracture were smaller at the center of the aperture and larger near the fracture surface. In rough fractures, the individual bubbles spanned across the aperture and behaved like individual-lamella porous media foam. For oil and gas production, high apparent foam viscosities from stable foam structures in rough fractures can increase displacement efficiency and oil recovery over gas injection.