Petroleum includes all naturally occurring carbonaceous liquids such as crude oil, natural gas, and natural asphalts. Petroleum is very common in small amounts and is widely distributed, however, it is rare that large accumulations that contain commercially important quantities are found.
Commercial accumulations of petroleum are dependent on technical, economic and political factors that influence whether an accumulation is worth developing in the existing circumstances. Profitability is based on the following factors:
- Geographic position,
- Properties and amount of oil or gas,
- Operations cost including drilling, production, and refining,
- Fiscal regime, and
- Political stability.