Hydrocarbon fields below the Earth's surface are distributed extremely irregularly in geological space and in time. More than 226 oil and gas bearing sedimentary basins have now been discovered on Earth, in which approximately 50,000 crude hydrocarbon fields with proven oil reserves of 152 billion tonnes have been discovered. However, only a few of the basins (the Persian Gulf, West Siberia, Volga-Ural, Timan-Barents Sea, Mexican and Mediterranean basins) have reliably estimated reserves exceeding 25 billion tonnes. The total proven oil reserves in these six basins represent roughly 80% (120 billion tonnes) of total world reserves, while the other 220 basins contain only 20% (32 billion tonnes) .
Of the vast number of oil fields, the majority of the reserves (>80%) are also concentrated in a small number of large and unique targets, the overwhelming majority of which are concentrated in two unique oil and gas basins (the Persian Gulf and West Siberian basins) and four large basins. The regions of maximum accumulation of crude hydrocarbons are associated with the stratigraphic levels of two geological eras: the Mesozoic (72%) and Middle-Late Paleozoic (22%). Due to this clearly pronounced irregularity in the concentrations of oil and gas fields in geological space and time, a minerogenic forecast analysis of oil and
gas presence must be performed with consideration of the particular features of the locations of the largest oil and gas bearing sedimentary basins in Russia and worldwide.
Last date updated on July, 2014