This book examines the theories surrounding the origin of oil and the formation of hydrocarbon fields from a hydrogeological perspective. This valuable research perspective is often overlooked, yet it is the deep petroliferous basins that hold the most hydrocarbon accumulations. The fluids at these levels play a crucial part in the formation, preservation, and destruction of mineral deposits. Discovering just how the fluids are formed could shed light on many aspects of practical geology. The book analyzes local and regional regularities in the formation of deep fluids in petroliferous basins. The text discusses the many different theories of oil origin and includes a summary of the theoretical, experimental, and empirical data on petroliferous basins obtained by geochemical, geodynamic, fluidodynamic, and other studies. The authors present existing views on the geodynamics of fluids at deep levels, explore in detail the development of abnormally high formation pressures and consider peculiarities in heat and mass transfer at deep levels for different regions. Key words: • Fluidodynamics • Petroliferous basins • Elision recharge • Hydrocarbon accumulations • Oil formations