Simulation Study of Foam Injection into Fractured Reservoirs using an Empirical Approach: Investigation of Matrix Wettability Effect on the Foam Performance

Gas injection has been used as an enhance oil recovery (EOR) method over last decades. However, due to low viscosity of gas and reservoir heterogeneity, this method has low recovery factor. Foam injection has been introduced as a solution to decrease gas mobility, and improve the ultimate oil recovery. In this study, the impact of wettability and capillary pressure on the foam performance has been investigated. In this regard, a fractured reservoir is developed, and three different wettability and capillary pressure condition has been tested. These conditions are changing the wettability from water-wet to mixed wet, along with an assumption of considering the capillary pressure or not. For better accuracy, different foam models were devoted to fracture and matrix. These models are similar to porous medium, and foam model parameters are a result of an optimization algorithm. The simulation outcomes reveal that the generation of foam within the fracture creates a viscous crossflow which leads to displacement of oil and higher recovery factors. The wetting state of the matrix determines the quality of foam, and matrix foam becomes more water-base, as wettability is altered from water-wet to mixed-wet. The results also show that matrix capillary pressure can create a capillary crossflow and harms the efficiency of foam injection by drying out foam in the fracture.