Study on the rheology of foam fracturing fluid with mixture model

Numerical simulation study on the rheology or foam fluid was carried through by treating inner phase as granular fluid with mixture model. The simulation results show that the gas phase is well distributed on cross-section. Besides, the higher the foam quality, the higher the velocity gradient near the wall. For turbulent properties, the turbulent kinetic energy and viscosity increase as the foam quality increases. With the same foam quality, the bigger the bubble diameter, the higher the turbulent viscosity and turbulent kinetic energy. What's more, the foam quality 63% is a catastrophe point at which the rheology of foam fracturing fluid changes sharply. The change trend of turbulent viscosity along radial direction is different between the regions where the foam quality is below and over catastrophe point, and in the latter the change trend is flatter. From the simulation results it can be seen that the mixture model is more applicable and effective to the region where foam quality is over 63%.