Associated gas comes from oil wells and this gas can exist separate from oil in the formation, or can be dissolved in the crude oil. Independent from the source of the natural gas, once separated from crude oil it commonly exists in mixtures with other hydrocarbons such as ethane, propane, butane, and pentanes. The impurities in associated gas cannot be used without treatment since it’s recovered during the oil production process.
In the past days, oil producers usually flared this unwanted oil during the production process. Due to the issues for environment consciousness and energy demands at site, to use associated gas for power generation at site becomes to a solution which creates high value utilization and avoid flaring in nowadays.
The composition of associated petroleum gas is often well suited for the combustion in gas engines. Depending on local demands, the waste heat from the engines can also be used for heating purposes at site. But dehumidification and removal of condensable hydrocarbons (HC) from the gas is generally required. Due to the often relatively high content of higher HC, a derating of the nominal natural gas output may be required. In the case of a high concentration of H2S, desulfurization of the gas may also be needed.
The benefits and advantages
- Avoiding GHG (Green House Gas) releases
- Use of waste by-product of the crude oil production process instead of diesel fuel to avoid costs for fuel transportation over long distances and storage at site.
- Independent, on-site power supply
- Electrical efficiency of more than 40%, and up to more than 80% efficiency in the case of combined heat and power