LAUSR

There is a widely popular perception in the cementing community that the turbulent regime should be used where possible in primary cementing of oil and gas wells. We conduct a detailed numerical study and analyze turbulent annular displacement flows. In particular, we show what roles viscous and buoyancy stresses play in the displacement efficiency. More importantly, we argue that the long-standing industry practice of preferring a turbulent displacement flow over laminar is over-simplistic and questionable. Indeed, we demonstrate that if the flow rate is increased very much when turbulent, steady displacements will be lost.