A new technique for determining the formation’s thermal conductivity based on the cylindrical probe with a constant heat flow rate

The thermal conductivity of geological formations is a parameter used to estimate the terrestrial heat flow and the geothermal energy resources. This parameter is also essential in environmental studies and the search for hydrocarbons and underground water reserves. A new technique has been developed to determine thermal conductivity formation by constant heat flow.
Earlier, Eppelbaum and Kutasov (2013) analyzed the case of the cylindrical probe with a variable heat flow rate. However, as indicated by experience, in geophysical practice, frequently observed situations have constant (or quasi-constant) heat flow rates. This statement simplifies calculations and allows for more accurate results. It is assumed that core samples or cuttings could determine dry formation density, porosity, and pore fluid saturations. In this case, the volumetric specific heat of formations can be estimated. It is also assumed that the transient temperature-time data are available for a cylindrical probe with a constant heat flow rate placed in a wellbore. The widely known Newton method was used to solve the problem. A semi-analytical equation describing the temperature of the probe wall is used to determine the formation conductivity. The formation thermal diffusivity is also calculated. Finally, a simulated example is presented.