Determination of Surface Heat Flow in Mazesta (USSR)

Abstract

A great number of temperature measurements in deep bore-holes are made on the territory of the Soviet Union. The results of these measurements are partly systematized in the work Problems of Geothermie t1). However they can be hardly used for the calculations of heat flow because of the absence of the corresponding determinations of the thermal conductivity of rock cores taken directly from these boreholes. In the present paper the temperature gradient and the thermal conductivity of samples of rocks for the same place are determined and by means of these data the value of the thermal flow is estimated. For temperature measurements the electric resistance thermometer was used that is designed by Dergunov I. D. and improved for the conditions of work in deep bore-holes (up to 4-5 km) at rather high pressures and temperatures. The electrical resistance was measured by means of the compensation methods by a special potentiometer and a high sensitive mirror galvanometer. Four bringing wires are used for doing away with the erratic currents and the influence of the wires. As a result of it the accuracy of the temperature measurements is about 0.01°C. Fig. 1 represents the exterior of the apparatus and the thermometer. The thermometer is a hollow cylinder on the surface of which a copper wire is winded bifllarily, whose resistance is measured. When the cylinder is buried into a bore-hole it is washed by a solution from outside and inside. Together with the application of ftorplast isolation this decreases the thermal inertia of the thermometer down to 1.5 sec. For the sake of strength annular justs are made on the cylinder. The thermometer stands the pressure up to 600 atm and the temperature up to 200°C.