Effect of gap and flow orientation on two-phase flow in an oil-wet gap: Relative permeability curves and flow structures

• ∼30% Of world oil contained in fractured rock where fractures are main flow path.
• Oil–water flow regimes within fracture key to improving oil recovery.
• Hele-Shaw apparatus built to study the flow of oil–water to examine flow patterns.
• Experimental results flow regimes depend on fracture and flow orientation.
• Results reveal that both phases can flow in both continuous and discontinuous forms.

Naturally fractured reservoirs contain about 25–30% of the world supply of oil. In these reservoirs, fractures are the dominant flow path. Therefore, a good understanding of transfer parameters such as relative permeability as well as flow regimes occurring in a fracture plays an important role in developing and improving oil production from such complex systems. However, in contrast with gas–liquid flow in a single fracture, the flow of heavy oil and water has received less attention. In this research, a Hele-Shaw apparatus was built to study the flow of water in presence of heavy oil and display different flow patterns under different flow rates and analyze the effect of fracture orientations on relative permeability curves as well as flow regimes. The phase flow rates versus phase saturation results were converted to experimental relative permeability curves. The results of the experiments demonstrate that, depending on fracture and flow orientation, there could be a significant interference between the phases flowing through the fracture. The results also reveal that both phases can flow in both continuous and discontinuous forms. The relative permeability curves show that the oil–water relative permeability not only depends on fluid saturations and flow patterns but also fracture orientation.