section_path: Abstract
section_name: Abstract
paragraph_text: Petroleum or crude oil, also referred to as simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that consist of refined crude oil.
  
  Petroleum is primarily recovered by oil drilling. Drilling is carried out after studies of structural geology, sedimentary basin analysis, and reservoir characterization. Unconventional reserves such as oil sands and oil shale exist.
  
  Once extracted, oil is refined and separated, most easily by distillation, into innumerable products for direct use or use in manufacturing. Products include fuels such as gasoline (petrol), diesel, kerosene and jet fuel; asphalt and lubricants; chemical reagents used to make plastics; solvents, textiles, refrigerants, paint, synthetic rubber, fertilizers, pesticides, pharmaceuticals, and thousands of others. Petroleum is used in manufacturing a vast variety of materials essential for modern life, and it is estimated that the world consumes about 100 million barrels (16 million cubic metres) each day. Petroleum production can be extremely profitable and was critical to global economic development in the 20th century. Some countries, known as petrostates, gained significant economic and international power over their control of oil production and trade.
  
  Petroleum exploitation can be damaging to the environment and human health. Extraction, refining and burning of petroleum fuels all release large quantities of greenhouse gases, so petroleum is one of the major contributors to climate change. Other negative environmental effects include direct releases, such as oil spills, as well as air and water pollution at almost all stages of use. These environmental effects have direct and indirect health consequences for humans. Oil has also been a source of internal and inter-state conflict, leading to both state-led wars and other resource conflicts. Production of petroleum is estimated to reach peak oil before 2035 as global economies lower dependencies on petroleum as part of climate change mitigation and a transition towards renewable energy and electrification. Oil has played a key role in industrialization and economic development.