Numerical Investigation of the Most Affecting Parameters on Foam Flooding Performance in Carbonate Naturally Fractured Reservoirs

Abstract

As one of the methods for reducing gas mobility and delaying gas breakthrough time, foam flooding has potentials to play a crucial role in the oil industry. Thus, being used in highly heterogeneous reservoirs, e.g., naturally fractured reservoirs, it can increase sweep efficiency. In this paper, a conceptual 3D model has been used for demonstration of influential factors on foam flooding in naturally fractured reservoirs. A series of numerical analysis on fracture and matrix permeability, fracture spacing, wettability, and foam parameters have been conducted. Furthermore, an investigation of certain phenomena, including diffusion and the block-to-block effect, has been conducted. Based on the simulations, increasing fracture permeability increased GOR in foam flooding, while increasing matrix permeability decreased it. Moreover, regardless of the intensity of the fracture in the models, the foam decreased the gas rate and increased the oil recovery. However, cases with higher fracture spacing ended up having higher GORs. Foam injection performed very well in both water-wet and oil-wet scenarios; however, it performed better in the oil-wet case. While consideration of diffusion increased GOR in model with very low matrix permeability, taking the block-to-block effect decreased GOR and increased oil recovery in all scenarios. Furthermore, the foam injection rate was one of the most critical variables that needed to be optimized. In conclusion, the foam flooding not only tended to decrease GOR drastically but also increased oil recovery significantly in naturally fractured reservoirs. However, different rock, fluid, and injection properties can significantly change the results.