Oil reservoir
From Freepedia
An oil reservoir is often though of as being an underground "lake" of oil, but it is actually composed of hydrocarbons contained in porous rock formations.
Contents |
Origin and accumulation
The hydrocarbons found in oil reservoirs forms from the remains of living things and are also known as fossil fuels. Petroleum, one kind of fossil fuel, is formed in the earth's crust and is also called crude oil. Scientists believe that millions of years of heat and pressure changed the remains of huge prehistoric sea animals and plants into crude oil and natural gas.
Production
To obtain the contents of the oil reservoir, it is necessary to drill into the earth's crust.
Types
In order for an oil reservoir to form, it must be shaped in a way to prevents the escape of hydrocarbons that migrate into it. Geologists have classified two types of reservoir shapes, or traps:
- Strudtural traps are formed by a deformation in the rock layer that contains the hydrocarbons (e.g., fault traps and anticlinal traps).
- Stratigraphic traps are formed when other beds seal a reservoir bed or when the permeability changes within the reservoir bed itself.
A reservoir can also be a combination of the two kinds of traps.
