Principles of temperature mapping

Temperature mapping can be performed by observing temperatures at different depths and by calculating mean gradients for the formations. Temperatures are calculated between wells by using surface temperature and interpolated mean gradients for each formation. Basicly this principle differs from usual technique by using interpolation of mean gradients instead of interpolating mean conductivity and heat flow. In cases where interpolation of gradients are impossible due to insufficient data the gradients can be found by using the relations of the mean gradients for sedimentary sequences. Measurements of conductivity on core samples will contribute to the temperature mapping if the sampling is intensive and the porosity distribution of the formation is known, but unfortunately this is very often not the case.

Calculation of subsurface temperature is important in connection with geothermal energy exploration and the study of maturation of organic matter. This last point was the main reason why a study of subsurface tempe rature in the Danish Central Graben was performed (Jensen 1983).