Abstract
The role of excess pressures in catagenic processes of the South-Caspian basin (SCB) is investigated. The results allow one to conclude that the SCB (mainly its deep-water part) is characterized by retardation of the transformations from kerogen to oil and of oil to gas, and also by a delay in the transformation of smectite to illite in clay minerals. Periodic intensification of these processes can enhance the development of mud diapirs and mud volcanoes, which act as focal centers for impulsive unloading of hydrocarbon products. The conclusion is that there are increased chances of large hydrocarbon accumulations in the deeply buried overpressured formations.
