Fossil fuels are the only non-renewable energy sources on which the world economy is based directly affect development. The main producer countries are located in the Middle-East (oil) and Russia and Middle East (gas). The oil search began in 1860 and has had a significant development during the Second World War, and in particularly in the post-war development, linked to the reconstruction. The formation of hydrocarbons is linked to the presence of fine-grained rocks (shales and limestone) that contain organic matter (1-14%), of vegetable (such as algae and leaves) and animal origin (microorganisms). When the rocks that contain this organic substance are buried subjected to high lithostatic load and the temperature reaches about 90°C, the organic matter begins to be transformed and at a temperature of about 120°C, begins to form oil, and at a temperature of about 140°C, gas is generated. After generation and migration the hydrocarbons accumulate in porous rocks (reservoirs), characterized by a geometry structures allowing their accumulation. Above the reservoir there should be a fine-grained and impermeable rock, that does not allow oil to disperse. In recent years, oil & gas companies have started to invest on non-conventional hydrocarbons, in particular, represented by shale gas and oil sands. To date, proven oil reserves amounted to 1.333 billion barrels of oil and 187.490 billion cubic meters of gas, reserves estimated to last for about approximately 50 years. If we add unconventional hydrocarbon reserves available and take into account the current consumption rate we could estimate that we would have oil for about 100 years more.