Oil and gas
Oil and Gas Deposits
06/04/2010
Both crude oil and methane gas are hydrocarbons that are formed deep underground. Oil and gas deposits are found all over the world. However, a number of conditions have to be met before these reserves can be formed. In fact, the genesis of oil is a long, slow process, with a number of fundamental stages that take place over tens of millions of years.
When oil engineers study an area, they check that these different stages have indeed taken place. This allows them to determine whether a deposit is viable and if it will produce high quality oil or gas.
How Oil and Gas Deposits Are Formed
Source rock is rich in organic matter that is converted into crude oil and methane gas after a long period of maturation, in an environment that reunites certain chemical, physical, and geographical conditions.
How Hydrocarbons Migrate to the Earth's Surface
While moving upwards towards the earth's surface, oil and gas sometimes penetrate and accumulate in reservoir rocks. Before a deposit can be formed, these stocks must be sealed in cap rocks that impede the hydrocarbons' escape from the reservoir rock.
Hydrocarbon Entrapment
In order for a deposit to be useable, it must contain significant amounts of oil or gas, which are trapped in rocks that form a closed volume. This protects the hydrocarbons from outside attacks from air or bacteria that could alter them.
