According to diverse studies, in 2002 there were in the world between 990 thousand millions and 1.1 trillion barrels of oil to extract. This means that to the current rhythm of world consumption these reservations would be drained by the year 2043, but it could be earlier if the energy consumption increase, as is expected to happens on the developing countries. However, these forecasts don't include the discovery of new wells or the possibility of extracting petroleum on areas that nowadays are considered as natural reservations and therefore, non exploitable. The dependence on oil of our society is manifested by the fact that in 1880 the world production, located almost completely in the United States, was less than a million of tons. Today the production overcomes the 3 thousand 500 million tons.