NG The natural gas used by consumers is composed almost entirely of methane. However, natural gas found at the wellhead, although still composed primarily of methane, is not as pure. It contains a mixture of other elements such as ethane, propane, carbon dioxide, nitrogen (The list is very long.) These are known as Natural Gas Liquids or NGL. It may also contain steam or steam condensate if the well is a cyclic steamer.
Raw natural gas comes from three types of wells: oil wells, gas wells, and condensate wells.
Properties
| Hydrocarbon | Formula | Gas Well | Petrol Well | Sales Quality |
|---|---|---|---|---|
| Methane | CH4 | 70-98% | 50-98 | 87-96% |
| Ethane | C2H6 | 1-10% | 4-21% | 1.5-5.1% |
| Propane | C3H8 | <5% | <15% | <1.5% |
| Butanes | C4H10 | <2% | <7% | trace* |
| Pentanes | C5H12 | <1% | <3% | trace* |
| Hexanes | C6H14 | <0.5% | <1% | trace* |
| Heptanes+ | C6H14 | <0.5% | <2% | trace* |
| Non-Hydrocarbon | Formula | Gas Well | Petrol Well | Sales Quality |
| Nitrogen | N2 | <15% | <10% | <5.6% |
| Carbon Dioxide | CO2 | <5% | <5% | trace* |
| Hydrogen Sulfide | H2S | <3% | <6% | trace* |
- Trace indicates less than 0.25%
