Geological prospecting and exploration for oil and gas is a set of industrial and R&D activities for geological study of subsurface resources, identification of promising areas, discovery of fields, their evaluation and pre-development. The final objective of geological prospecting is preparation of subsurface resources. The main principle of geological prospecting is the comprehensive geological study of subsurface resources when along with oil and gas exploration all associated components (petroleum gas and its composition, sulfur, rare metals, etc.), possibility and practicality of their production or utilization are investigated; hydrogeological, mining, engineering, geological and other studies are performed; natural, climatic, socioeconomic, geological and economic conditions and their changes caused by future field development are analyzed.