The Sant Corneli anticline in the Southern PyreneesThe Sant Corneli anticline in the Southern Pyrenees

A hydrocarbon accumulation forms when six fundamental elements to develop in the correct sequence: the source for the hydrocarbon (any carbon bearing element such as plants or marine plankton), maturation (enough heat and pressure), migration (movement of the hydrocarbon from deep in the subsurface to shallow), reservoir (a porous sedimentary rock in which the liquid or gas hydrocarbon can be held), trap, and seal (something preventing the hydrocarbon from leaking out).