Energy

Elements that form an oil field

Hydrocarbons, being light and not very dense, tend to rise while they migrate. If they do not find obstacles on their ideal pathway, they scatter in the overlying rocks until they reach the surface and give rise to spontaneous evidence: the so-called oil seepage that remains on the surface. In short, for an important oil field to form it is necessary that the rock formations that surround the mother rocks should be able to trap and accumulate hydrocarbons within, and require three indispensable conditions:

• the presence of a rock that can contain the hydrocarbons, the so-called reservoir;
• the reservoir rock must be bounded by an impermeable rock, called ‘cap rock’, capable of stopping the migration of fluids and of confining them within the reservoir;
• the disposition and configuration of the reservoir and cap rocks must be such that they form a rather capacious container with a shape suited to hold the maximum amount of hydrocarbons and constitute the so-called ‘trap’.