The disclosure presents a technique for predicting the composition of a borehole mud using a thermal conductivity parameter of the mud and a dilution liquid. The mud can be altered by conditions within the borehole, such as material, fluid, and temperature affecting the original mud composition pumped into the borehole location. The mud can be an oil-based, water-based, or another type of mud of a well system. The technique can extract a measured quantity of mud and place it into a mud container. A first thermal conductivity parameter can be calculated for the extracted mud. A dilution liquid can be mixed into the extracted mud in the mud container and a second thermal conductivity parameter calculation can be performed. From the calculated first and second thermal conductivity parameters, the composition of the mud, as well as the fractional proportions of the major components of the mud, can be predicted and computed.