A study on friction loss and holdup ratio in the water lubricated pipeline transportation of heavy oil

Core Annular Flow (CAF) is an economically efficient and environmentally sustainable technology for transporting heavy oil and bitumen, especially compared with conventional methods, such as truck hauling, dilution and heating. In CAF, heavy oil forms the core of the flow and a water sheath encloses this core by forming a continuous layer on the pipe-wall. Power requirements are orders of magnitude lower than those associated with the flow of heavy oil alone. One of the major obstacles to the large scale implementation of this technology is the unavailability of a reliable model for the frictional pressure loss. In this work, a computational fluid dynamics based modeling methodology is validated and analyzed with respect to the measured values of pressure losses in a CAF pipeline. Another subject of interest in the field of CAF hydraulics is modeling the holdup, which simply refers to the in situ volume fraction. The available models do not take into account the process parameters like mass flow rate, viscosity and density. A new modeling approach is introduced in this work that addresses the actual physics of holdup.