Oil is a fossil fuel that is used around the world for various purposes like lighting, transportation, and cooking. If we go by the facts, U.S., in 2009, produced 4.9 million barrels of crude oil every day and imported additional 9.8 million barrels from other nations around the world. Reservoir simulation helps to evaluate and predict oil and gas field performance through the recovery of different field development scenarios to assess the effects on the recovery of various operational conditions.

Crude oil is refined to manufacture petroleum products like gasoline, kerosene and other heating oils. To meet the requirements of energy, the oil industry has to look for new sources of petroleum and to improve the production of existing refineries. This means regular maintenance tasks.

How does the oil formation take place?

Oil gets secreted from the fossils of animals and plants that died between 10 million to 600 million years ago- both underground and under oceans. The leftovers of dying plants and animals sink down to the earth's crust. Over many years, they sink to the sedimentary layer of the earth where the presence of oxygen is either very less or none at all.

Conditions like these invite the anaerobic micro-organisms to invade these layers and decay the leftovers into compounds enriched in carbon that form organic layers. This organic material thus formed gets mixed into the sediments and takes the shape of fine grained rocks or shale.

The newly formed sediments exert heat as well as pressure on the surrounding environment. This heat along with pressure in turn distills the sediments to natural gas and oil. The oil flows from the main rock and gets accumulated in the absorbent limestone or sandstone known as reservoir rocks.

The trapped fossils in the earth's crust between the layers of the impermeable rocks, or cap rocks (such as marble or granite) produce movement effects that include folding, faulting and pinching out.

· Folding: It is the horizontal movement of the crust that forces the rock layer to move upwards, forming a fold.

· Faulting: It is the result of cracks on rocks that shift to one side- either upwards or downwards.

· Pinching out: It results when an impermeable rock layer is squeezed upwards into a higher positioned reservoir rock.

With the help of fossils, petroleum was made over several thousand years. Later, geologists found these reserves by specially designed instruments. Now everything is done under a contract if a company wants to setup a drilling process. Middle East nations are rich in oil reserves. Oil, as a fuel, was discovered five thousand years ago when it was drilled from the ground. Ever since, it has been a major industry for the entire world.

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