Color
The color of crude petroleum is very rich. There are deep red, golden, dark green, black, maroon and transparent. The color of crude oil is determined by the content of colloid and asphaltene contained in it. The more the oil contains, the deeper the color is. In China’s Chongqing Cucumber Mountain and North China Dagang Oilfield have well-produced colorless oil. Karamay oil is brown to black. Daqing, Shengli and Yumen oil are all black. Colorless oil is produced in California, the Former Soviet Union Baku and Romania and Indonesia’s Sumatra. The formation of colorless oil, may be related to the adsorption of colored colloid and asphaltene by rocks during migrating. However, different degrees of dark oil account for an absolute majority, almost over the world’s major petroliferous basins.
Composition
Material Composition.
The main composition of crude oil is oilness (this is the main composition), colloid(a viscous semi-solid substance), asphaltene (dark brown or black brittle solid material), carbonaceous(a non-hydrocarbon). Petroleum is a mixture of of hydrocarbons, a colored, flammable oleaginous liquid with a special odor. Natural gas is composed of various gases, mainly composed of gaseous hydrocarbons, and has a special odor, colorless and a flammable mixed gas. The division of labor of the entire petroleum system is also detailed. The chemical substance that make up the petroleum can be decomposed by distillation. As a processed product, the crude oil has kerosene, benzene, gasoline, paraffin, asphalt etc. Strictly speaking, petroleum is mainly composed of hydrocarbon composed of hydrogen and carbon. The four hydrocarbons with the smallest molecular weight are all gas.
Elemental Composition
Petroleum is mainly of hydrocarbon. It consists of a mixture of different hydrocarbons. The chemical elements that make up petroleum are mainly carbon (83% ~ 87%), hydrogen (11% ~ 14%), and the rest are sulfur (0.06% ~ 0.8%), nitrogen (0.02% ~ 1.7%), oxygen (0.08% ~ 1.82%) and trace metals (nickles,vanadium,iron,antimony etc.) Hydrocarbons composed of carbon and hydrogen make up a major component of petroleum, accounting for 95% to 99%. Various hydrocarbons are classified according to their structure: alkanes, cycloalkanes, and aromatic hydrocarbons. Natural petroleum generally contains no olefins and secondary processed products often contain varying amounts of olefins and alkynes. Sulfur, oxygen and nitrogen-containing compounds are harmful to petroleum products and should be removed as much as possible in petroleum processing.
Distribution
The distribution of crude petroleum is extremely un-balanced in general: from the east-west hemisphere, about 3/4 of the petroleum resources are concentrated in the eastern hemisphere and 1/4 in the western hemisphere. From the southern and northern hemisphere, the petroleum resources mainly concentrate in northern hemisphere. It is mainly concentrated in two latitude bands of 20°-40° north latitude and 50°-70°north latitude. Both the Persian Gulf and the Gulf of Mexico and the North African oilfield are within 20°-40° north latitude. The band concentrates 51.3% of the world’s petroleum reserves. The 50°-70° latitude zone has the famous Beihai oilfield, Russia Volga and Siberian oilfield, and Alaska Bay oil area. About 80% oil reserves that can be mined are located in the Middle East. 62.5% of which are located in Saudi Arabia(12.5%),the United Arab Emirates, Iraq, Qatar and Kuwait.
Africa
Africa is the region with the fastest growth in crude oil reserves and oil production in recent years and known as the ’second Gulf region’. In 2006, Africa’s proven crude oil reserves were 15.62 billion tons, mainly distributed in the Gulf of Guinea region of West Africa and North Africa.
Libya, Nigeria, Algeria, Angola and Sudan rank among the top five African crude oil reserves. Nigeria is the largest oil producer in Africa. Oil production in five countries, Nigeria, Libya, Algeria, Angola and Egypt accounts 58% of the total amount in Africa.
