Methods to Invert Temperature Data and Heat Flow Data for Thermal Conductivity in Steady-State Conductive Regimes

Temperature and heat flow data carry specific information about the distribution of thermal conductivity variations which is not available in other geophysical data sets. Thus, thermal data constitute important complementary data sets in the multiphysics-based imaging and characterization of earth's subsurface. The quantitative interpretations that accompany this effort can be carried out by determining thermal conductivities from temperature or heat flow data. Towards this goal, we develop inversion methods based on Tikhonov regularization and numerical solution of the differential equations governing the steady-state heat equation. Numerical simulations using these methods yield insights into the information content in thermal data and indicate it is similar to that in potential-field data. We apply the temperature inversion method to borehole temperature data from the Cooper Basin in Australia, a well-studied geothermal prospect. The methods and insights presented in this study pave the way for imaging the subsurface through recovered thermal conductivities and for joint quantitative interpretations of thermal data with other common geophysical data sets in various geoscientific applications.