EFFECT OF FRACTURE AND FLOW ORIENTATION ON TWO PHASE FLOW IN AN OIL WET FRACTURE: RELATIVE PERMEABILITY CURVES AND FLOW STRUCTURES

Naturally fractured reservoirs are among the most complex reservoirs for heavy oil production. A series of laboratory experiments were done to study/visualize the complexity of co‑current water‑heavy‑oil flow in a fracture by using a Hele‑Shaw cell. In these experiments, the effect of fracture and flow orientation, fluid properties and different forces on relative‑permeability curves and flow structures have been evaluated. Application: Flow in fractures and relative‑permeabilities are not well understood. It is obvious that inaccurate relative‑permeability curves lead to large errors in recovery prediction. The results of this study can be applied in reservoir characterisation and numerical simulations. Fracture flow regime maps can be used for reservoir management and production optimization. Results: New relative‑permeability model that accounts for flow and fracture orientation has been proposed and compared to other published models. Flow structure for different flow and fracture orientations were compared each other and with published ones. The results reveal complexity involved in fracture dominated flow and high interference between phases that can only be modeled by using the proposed model. Results show that oil‑water relative‑permeability is not just function of saturation but also fluid and fracture properties, orientation and flow pattern. In contrast with many studies, two‑phase flow in continuous and discontinuous forms was observed. Flow maps derived in this research include numerous new experimental data. Significance: This paper reveals the significance of relative‑permeability curves in reservoir characterization and its complexity. The visualized two‑phase flow structure in the fracture and the transition between the flow regimes provides more understanding of fracture flow dynamics. Given that numerical/analytical reserve and recovery prediction depends strongly on relative permeability, the results of this study help us to simulate and predict flow in fractured reservoir rock more accurately.