ASSESSMENT OF THE POSSIBILITY OF EXPLORING THE WELL'S BACKWATER SPACE BY ACTIVE THERMOMETRY

Abstract

The use of active thermometry based on local induction heating of the casing string has prospects for solving environmental problems in the study of idle wells. With an inductor power of 1 kW, even with small heating times, it is possible to create and register temperature anomalies in the casing.This article explores the possibility of using active thermometry to solve environmental problems in the study of idle wells.The idea is to measure the temperature of the casing before and after heating by the inductor for a certain time. Obviously, with fixed inductor power and heating time, the change in temperature of the section of the casing string heated by the inductor will depend on the heat exchange between the casing string, the downhole environment and the environment in the annular space. In this case, the conditions of heat exchange with the down hole environment at different depths may remain the same, but with the external environment surrounding the column may change. The reason for this may be a change in the contact of the column with the cement, the properties of the cement, the presence of vertical or horizontal fluid flows behind the well, etc.The paper presents a new analytical solution for calculating unsteady temperature in a metal casing caused by induction heating of a section of the column. The solution is based on a one-dimensional analytical model that takes into account heat exchange between the fluid and the casing, heat generation in the metal column when the inductor is turned on, and heat conduction losses in the cement and rock. To obtain a solution, the Laplace integral time transform method was used.The results of the study show that the amount of heating of the column changes depending on changes in heat exchange conditions and changes in the thermal activity of the environment behind the column. Significant differentiation of temperature along the depth of the well can be caused by a violation of the tightness of the cement ring, the movement of formation water and annular flow. This creates the prerequisites for using the active thermometry method to solve environmental problems in developed oil fields.