CHARACTERISTIC PROPERTIES OF THE THERMAL FIELD IN AN IDLE WELL WITH AN INDUCTION HEATER IN THE PRESENCE OF BEHIND-CASING FLUID MOVEMENT

The characteristic properties of the fi elds of local fl uid velocity and temperature of an idle well (in the absence of fl uid motion in the borehole) have been investigated under the conditions of local induction heating of a metal pipe (casing string, or pipe) in the presence of behind-casing fl uid movement, viz., vertical fl uid fl ow passing over the pipe on the outside, on the basis of a numerical solution of the Navier–Stokes equation in the Oberbeck–Boussinesq approximation in the Ansys Fluent engineering package. It has been established that in the absence of behind-casing fl uid movement, the region of disturbance of temperature and local fl uid velocity fi elds in which a vortex motion is formed due to natural heat convection does not exceed 1.5 m above the heating area. If there is fl uid movement, the size of the perturbed region displays a multiple vertical increase, which results from the casing pipe′s warmup above the area of induction impact due to heat exchange with an ascending fl ow in the casing string borehole annulus. The sensitivity of the temperature of the inner casing pipe surface and the borehole fl uid temperature to the presence of behind-casing fl uid movement has been demonstrated. Qualitative and quantitative criteria indicating the presence of behind-casing fl uid movement above the induction heating area have been suggested. A comparison has been made of the results of numerical calculations with the experimental data obtained using a laboratory setup.
The characteristic properties of the fi elds of local fl uid velocity and temperature of an idle well (in the absence of fl uid motion in the borehole) have been investigated under the conditions of local induction heating of a metal pipe (casing string, or pipe) in the presence of behind-casing fl uid movement, viz., vertical fl uid fl ow passing over the pipe on the outside, on the basis of a numerical solution of the Navier–Stokes equation in the Oberbeck–Boussinesq approximation in the Ansys Fluent engineering package. It has been established that in the absence of behind-casing fl uid movement, the region of disturbance of temperature and local fl uid velocity fi elds in which a vortex motion is formed due to natural heat convection does not exceed 1.5 m above the heating area. If there is fl uid movement, the size of the perturbed region displays a multiple vertical increase, which results from the casing pipe′s warmup above the area of induction impact due to heat exchange with an ascending fl ow in the casing string borehole annulus. The sensitivity of the temperature of the inner casing pipe surface and the borehole fl uid temperature to the presence of behind-casing fl uid movement has been demonstrated. Qualitative and quantitative criteria indicating the presence of behind-casing fl uid movement above the induction heating area have been suggested. A comparison has been made of the results of numerical calculations with the experimental data obtained using a laboratory setup.
Author:  F. F. Davletshin, R. Z. Akchurin, A. Sh. Ramazanov, R. A. Valiullin, R. F. Sharafutdinov, and I. V. Kanafin
Keywords:  induction heating, temperature, fresh-water horizons, idle well, behind-casing fl uid movement, natural heat convection
Page:  385