Petroleum Chemistry and Composition

Petroleum Chemistry

• Petroleum, also known as crude oil, forms under the Earth's surface in rock formations.
• It's extracted by drilling wells through the Earth's crust to reach oil reserves.
• Crude oil is a dark brown, viscous liquid, sometimes greenish.
• It's a mixture of approximately 150 different organic compounds, mostly aliphatic hydrocarbons, with smaller amounts of aromatics and sulfur/nitrogen compounds.
• Large quantities of natural gas are often associated with petroleum.
• Petroleum is valuable for transportation, commerce, and industry. A country's prosperity depends on its petroleum reserves.

Petroleum Composition

• Petroleum, in its strictest sense, includes only crude oil; in common usage, it also encompasses natural gas.
• Both crude oil and natural gas are primarily mixtures of hydrocarbons.
• Lighter hydrocarbons (methane, ethane, propane, butane) exist as gases under surface temperatures and pressures.
• Heavier hydrocarbons (pentanes and above) are liquids or solids at these conditions.
• The proportion of gas or liquid hydrocarbons in underground oil reservoirs varies based on conditions (pressure, temperature), influencing recovery.
• Oil wells typically produce a mixture of crude oil and dissolved natural gas.
• At the surface, lower pressure causes some gas to come out of solution as associated/solution gas.

Associated/Solution Gas and Condensate

• Gas wells primarily produce natural gas.
• Higher pressures and temperatures underground can lead to heavier hydrocarbons (pentane, hexane, heptane) remaining in gaseous form.
• When pressure and temperature decrease at the surface, these heavier hydrocarbons can condense into liquids and form natural gas condensate.
• Condensate resembles gasoline in appearance and composition.
• The proportion of hydrocarbon types within petroleum varies widely between different oil fields; heavier types range from 97% to as low as 50%.

Explore the fascinating world of petroleum, its formation, extraction, and composition. This quiz covers the different types of hydrocarbons found in crude oil and natural gas and their significance in various industries. Test your knowledge on how petroleum impacts commerce and transportation.