It is known that the formation of petroleum is associated with the development of sedimentary rocks deposited in the sea or close marine environments, and that it is the result of the decay processes of vegetal and animal organisms which in remote times were incorporated in such deposits.

Petroleum is not distributed uniformly in the sub-soil; at least four basic conditions must  converge for this to accumulate: a permeable rock, so that under pressure petroleum can move through the microscopic pores of the rock; an impermeable rock, that does not let the oil and gas leak to the surface; the deposit shall behave as a trap, because impermeable rocks are seated in such a manner that there is no lateral motion of the hydrocarbons leaks; and there will be a sufficient amount of the organic matter required to become petroleum by the  effects of pressure and temperature prevailing in the reservoir.

In its natural state it is considered a mineral; it can generate, through industrial processes products with a high value such as fuels, lubricants, waxes, solvents and petro-chemical products.

Importance Life without oil could not be as we know it. From crude oil we obtain gasoline and diesel oil for our cars and buses, fuel for ships and airplanes. We use it to generate electricity, obtain heat for factories, hospitals and offices and diverse lubricants for machinery and vehicles.

The petro-chemical industry uses oil products to produce plastic, synthetic fibers, detergents, medicines, food preservatives, rubber and agro-chemical products.

Petroleum has transformed the life of people and the economy of nations. Its discovery created wealth, modernity, prosperous industrial towns and new jobs, motivating the growth of such industries.