Abstract
In order to evaluate the effect of boundary conditions, particularly that of topography, on heat flow in mountainous areas utilization of boundary element method for solving Laplace's equation is proposed. Numerical solution by this method and the actual data of precise tem-perature logging are compared for a well located at the center of a valley in a two dimensional topographic profile, assuming non-uniformness of mean surface temperature due to the slope attitude of the ground surface. In the case of H-3 hole with a depth of 250 m in Sengan Area, observed temperature gradient decreases down to the bottom, which agrees well with the numerical solution with the undisturbed geothermal gradient value of 5.0×10-2°C/m. A comment is also made on the deviation of observed temperature gradient from the numerically generated temperature log at isolated short intervals.
