Quantitative Estimation of Hydrogeological and Geothermal Parameters by Experimental Data

Abstract

Statistical analyses of the results of the temperature measurements carried out in more than 400 long-standing deep boreholes located in Russia, Ukraine, Belarus and other regions have shown that, in most cases, the heat flow in the upper layers of sedimentary material is not constant. In active water-exchange zones and especially in areas of alimentation and discharge of underground waters, the prevailing influence on the thermal field is the convective heat flow component. For one example, the Pripyat depression (Belarus), the method of separation of conductive and convective heat flow components is developed, where the velocities of fluid motion are defined and the quantitative estimation of hydrological parameters is given by temperature measurements. For the comparison of the hydrological characteristics of investigated regions we introduce the concept of the specific convective heat flow, which is invariant about the fluid motion interval. The evaluation of heat flow is impossible without information on the thermal properties of rocks, specifically for heat conductivity and thermal capacity. These parameters are directly connected to the structural performance of rocks, in particular by porosity. Investigation of rocks, identical in elemental composition but with different porosities, has allowed us to make a quantitative connection between porosity and thermal capacity in a temperature range from 25 to 300oС.