INVESTIGATION OF TEMPERATURE FIELDS DURING LOCAL INDUCTION HEATING OF THE CASING STRING IN THE WELL

Abstract

One of the important tasks in geophysical studies of operating wells is the detection of behind the casing flows. The traditional complex of geophysical methods (thermometry, flow metering, composition methods, and others) does not always make it possible to detect the movement of fluid behind the well casing. To solve this problem, it is promising to use the method of active thermometry.Research technology using this method involves recording the temperature in the well during induction heating of a small section of metal casing. As a result of heat exchange between the heated section of the column and the liquid flow, a thermal disturbance is created in the annular flow channel. In the presence of behind the casing flow, heat will be carried away from the induction heating region in the direction of liquid movement and will be redistributed in the column above or below the heating interval. By recording the temperature of the casing during induction heating and after turning off the inductor, it is possible to establish the fact of cross-flow and quantify its flow rate.This paper studies the influence of the direction and flow rate of behind the casing flow on the unsteady temperature field in a metal casing during its local induction heating. The problem is solved numerically in the Ansys Fluent software package. The temperature field in the fluid in the wellbore is calculated taking into account free convection.The model temperature distributions obtained for different behind the casing flow configurations (direction, flow rate) can be used for quantitative interpretation, to determine the flow rate in the behind the casing flow channel by comparing actual and model temperature curves. To assess the intensity of behind-the-casing movement, time measurements at a “point” in the induction heating interval are also informative. The direction of flow is determined by the nature of the temperature distribution in depth above and below the induction heating section.