Comparing laminar and turbulent primary cementing flows

Abstract There is a long standing perception in the cementing community that turbulent regime displacements should be used in primary cementing whenever possible. In this paper, we question this preference and provide evidence that such statements often lead to erroneous conclusions. We show that there is no clear indication that turbulent displacement always outperforms laminar displacement. Indeed, we will show examples where a lower Reynolds number laminar flow outperforms its turbulent counterparts. Our study emphasises that comparisons must always be made within the context of operational constraints, which usually means a bound on frictional pressure regardless of flow regime. Instead of flow regime being the most critical factor, our analysis identifies eccentricity of the annulus as the single most important parameter that significantly influences the displacement outcome. The second contributing factor, in a vertical casing, is the density difference of successive fluids pumped in the annulus.