Session: 11-05-02 Well Cementing Theory & Practice-2

Paper Number: 79753

79753 - Experimental Study of Newtonian Laminar Annular Horizontal Displacement Flows With Rotating Inner Cylinder 

During the primary cementing of oil and gas wells, it is increasingly becoming common to slowly rotate the inner casing to aid the mud displacement. We present an experimental study of laminar displacement of Newtonian fluids with rotating inner cylinder. Dimensionless analysis shows that such displacement flows in a horizontal eccentric annular geometry are governed by nine dimensionless parameters. However, following the usual scaling arguments for narrow annulus flows, the number of dimensionless parameters is reduced to five: eccentricity, viscosity ratio, Reynolds number, dimensionless casing rotation speed, and buoyancy number. A carefully designed series of experiments are conducted to investigate the dependency of the flow dynamics on each dimensionless parameter. We consider Newtonian fluids in the study, which are prepared by mixing water with sugar or glycerol to vary the density and viscosity.

We study a wide range of rotational speeds, ranging from 15 to 60 rpm, which are typical of field conditions. The inclusion of casing rotation is able to accelerate the displacement and increase the displacement efficiency with increasing rotational speed, which acts by shearing the fluids azimuthally and facilitating the movement of the narrow side. Under certain conditions the casing rotation is able to change the stratified flow behavior, for both slumping and wide side flows as observed in Renteria & Frigaard (J. Fluid Mech., vol. 905, 2020, A7). The resulting flows can be classified as either azimuthal dispersion or helical displacements. Azimuthal dispersion displacements are found for buoyancy-dominant cases, and the displacing fluid is dispersed uniformly around the azimuthal direction. Helical displacements are found for rotation-dominant cases, and leave behind layers of slowly thinning displaced fluids due to dispersion.

Another notable benefit of casing rotation is improved displacement of bottom side residual fluid. Such phenomenon often can be found for slumping displacements with high buoyancy and eccentricity. Casing rotation can forcefully shear the residual fluid and move it to the wider side, whereas the displacing fluid is directed to the bottom side. The effect of the viscosity ratio is studied by comparing iso-dense fluid pairs with different viscosity ratios. Higher viscosity ratios limit the dispersion of the displacing fluid both axially and azimuthally and the fluid is more constrained along the streamlines.

Presenting Author: Heeseok Jung University of British Columbia

Authors:

Heeseok Jung University of British Columbia
Ian Frigaard University of British Columbia
Ruizi Zhang University of British Columbia
Alondra Renteria University of British Columbia