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Shell UK Exploration and Production, Shell-Mex House, Straud, London WC2R 0DX, UK
Shell Internationale Petroleum Moatschappij B.V., Postbus 162, 2501 AN The Hague, Netherlands
Venezuela has produced some 40 billion barrels of oil. Remaining recoverable reserves are currently in the order of 60 billion barrels of oil and 92 trillion cubic feet of gas. The Orinoco Heavy Oil Belt, the world’s largest known oil accumulation, has some 1.2 trillion barrels of oil-in-place. Only part of the 267 billion barrel, ultimate recoverable of this belt is included in the current reserves.
Most of Venezuela’s hydrocarbon reserves are located in the Maracaibo, Eastern Venezuela, and Barinas—Apure Basins, and most are derived from Upper Cretaceous, marine source rocks. Tertiary, terrestrial source rocks have also contributed hydrocarbons in the Maracaibo and Eastern Venezuela basins, and Tertiary marine and terrestrial source rocks have generated hydrocarbons in the Falcon and offshore Venezuelan basins.
The hydrocarbon habitat has been profoundly influenced by Mesozoic—Recent platetectonics. Many of the structural traps are the consequence of Carribbean—South America dextral relative movements. Some of these structures, mainly in the northwest, were enhanced by stress generated in the Pacific. The northern part of the country has suffered considerable shortening and inversion. The resultant mountain chains limit the modern hydrocarbon basins. Reconstruction of late Cretaceous source rock palaeogeography, of Late Cretaceous to Palaeocene kitchens (now metamorphosed), and of Eocene to Recent kitchens, shows that the latter are remnants of a much larger petroliferous province and provides an explanation for the great abundance of hydrocarbons in the area.
Significant volumes of hydrocarbons remain to be discovered in extrapolations of traditional and developing plays.
