Oil is composed hydrocarbon and was formed millions of years ago in the process that began when aquatic plant and animal remains were covered by the layers of sediment such as particle of rock and minerals. Different mixes of plant and animal remains as well as pressure, heat and time have caused hydrocarbons to appear today in a variety of forms for example crude oil, a liquid, natural gas, a gas and coal a solid. Even diamonds are a form of hydrocarbons. The word of petroleum comes from Latin words ‘Petra’ or ‘rock’ and ‘oleum’ oil. Oil is found in reservoirs in sedimentary rock. Tiny pores in the rock allowed the petroleum to seep in. There “reservoir rocks” hold the oil like a sponge, confined by other non porous layers that form a trap.

Reservoir rocks
The world consists of many regions with different geological features formed as the Earth’s crust shifted. Some of the regions have more and larger petroleum traps. In some reservoir rocks, the oil is more concentrated in pools, making it easier to extract, while in other reservoirs it is diffused throughout the rock. The Middle East is a region that exhibits both favorable characteristics which the petroleum trap are large and numerous and the reservoir rocks hold the oil substantial pools, the region dominance in world oil supply is the clear results. This are the example below:

World Oil Reserves By Regions 1st January 2005
Other regions also have large oil deposits , even if the oil is difficult to identify and more expensive to produce. The United States, with its rich oil history is such a region.
Drilling for oil
To identify a prospective site for oil production, companies use a variety of techniques, including core sampling, physically removing and testing a cross section of the rock and seismic testing. When the return vibrations from a man made shockwave and measured and calibrated. Advanced in technology have made huge...