Cement channeling: how to predict and prevent

Description of experiments with large-flow loop that measure the velocity of the interface between fluids of varying densities and rheologies. The single-fluid velocity profiles cannot be used to predict interfacial profiles between spacer and cement. The importance of turbulent flow in minimizing channeling-through mechanisms of increased frictional pressure drop and mixing across the annulus is confirmed. Large density differences, both negative and positive, also minimized channeling.