Turbulent Flow of Polymer Fluids Over the Sand Bed in Horizontal Concentric Annulus

Abstract

Turbulent flow of non-Newtonian fluids over stationary sand bed deposits are commonly encountered during the wellbore clean-out operations conducted to remove the cuttings (solids deposited as a result of drilling or post-fracking operations) from the horizontal wellbore. We have investigated the impact of the presence of a stationary sand bed deposit on the characteristics of the flow in a horizontal concentric annulus using Particle Image Velocimetry (PIV)technique. Velocity profiles, Reynolds stresses, and axial turbulence intensities are measured in the lower and upper half of the annulus to assess the impact of the sand bed on the flow. Results show that the presence of the sand bed causes the reduction of the volumetric flow rate in the lower part of the annulus with an associated decrease in the local fluid velocity and the flow turbulence. In the upper part of the annulus, however, increased level of turbulence and flat velocity profiles were observed.