The method of heat flow measurements studies the natural thermal field of the earth, caused by the internal heat sources and the thermal properties of rocks. When performing the thermal exploration, the temperature and its vertical thermal gradient or heat flow are recorded. The lateral and depth distribution of these parameters contains information about the thermal properties and geological structure of the explored region or object. Exothermic (heat-generating) and endothermic (heat-absorbing) processes occurring in oil and gas deposits appear in the thermal field in the form of local anomalies and represent a valuable prospecting indicator.