Device for measuring temperature in downhole during drilling

The paper presents a device for controlling the temperature of the drilling fluid in the borehole during drilling, made on the basis of the mechanical resonators, which have a high Q factor, accuracy and reliability. A model of the device consisting of a mechanical oscillatory system with the fixed permanent magnets and a transducer of mechanical vibrations into electrical ones is designed. The mechanical oscillatory system is formed as a cylindrical bimetal spiral, one end of which is rigidly fixed and the other is free. A transducer of mechanical vibrations into electrical ones is designed as a system of interacting magnetic fields of permanent magnets, fixed to the cylindrical bimetallic spiral, and the coils of driving and detaching of the vibrations that provide transverse vibrations of cylindrical bimetallic spiral. The experiment, in which a dependence of the oscillation frequency on the temperature was studied, is made. A theoretical calculation of the resonant frequency of the device at various temperatures is carried out. A comparative analysis of the experimental and theoretical dependencies of the frequency of the transverse vibrations of a cylindrical bimetallic spiral on temperature is made and the mean relative error of measurement is obtained.