JODI-Oil FAQ / What is crude oil? What does it include?
- Yui Torikata / IEF
Join Date:May 2011 Posted by Yui Torikata/ IEF / 28.05.2014 09:56Petroleum is a complex mixture of liquid hydrocarbons, chemical compounds containing hydrogen and carbon, occurring naturally in underground reservoirs in sedimentary rock. Petroleum is normally found at considerable depths beneath the earth’s surface, where, under pressure, it is essentially liquid. At the surface and under atmospheric pressure, petroleum comprises both natural gas and crude oil.
The word petroleum comes from the Latin word petra, meaning rock, and oleum, meaning oil. The word "petroleum" is often interchanged with the word "oil". Broadly defined, it includes both primary (crude oil or unrefined) and secondary (refined) products.
Crude oil is the most important oil from which oil products are manufactured, but several other feedstock oils are also used to make oil products. There is a wide range of petroleum products manufactured from crude oil. Many are for specific purposes, such as motor gasoline or lubricants; others are for general heat-raising needs, such as gas oil or fuel oil.
The quality of crude oil depends to a great extent on its density and sulphur content. The crude oils are classified as light, medium and heavy according to their density. Crude oils with high sulphur content (at least 2.5% sulphur) are sour, while sweet crude oils have often less than 0.5% sulphur content.
Because crude oil contains a wide range of hydrocarbons from the lightest to the heaviest, the characteristics including the density of individual crude oils vary greatly. Similarly, the density of the different petroleum products varies substantially between the products. The density can be used to classify petroleum products from light to heavy; where for example LPG is considered light at 520 kg/m3, fuel oil is a heavy product at over 900 kg/m3.
One critical issue is whether the volumes of NGL, lease or field condensates and oils extracted from bituminous minerals are included. All organisations exclude NGL from crude oil. If condensates are able to be excluded, it should be noted to the JODI organisation(s) of which the country/economy is a member. Most OPEC member countries exclude condensates.