What Is Associated Gas?

Definition Associated Gas

Associated gas is a term used to describe natural gas released in the course of production of crude oil. It comes in the same reservoirs that oil comes from that is trapped under pressure deep beneath. Contrary to non-associated gas that is found in reservoirs with no oil as well, associated gas is physically and chemically tied in a way to the crude extraction.

The gas composition generally comprises methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H10), as well as trace gases like nitrogen, carbon dioxide, and hydrogen sulfur. This makes it a versatile gas that can be utilized as a clean-burning fuel, processed into chemicals, or transformed into LNG.

How Is Associated Gas Formed?

The production of gas can be a result of the production of hydrocarbons within petroleum reservoirs. Over the course of millions of years, organic matter buried beneath sediment is exposed to pressure and heat. This creates crude oil, and under similar conditions, gases that disintegrate within the oil or build up over them in the gas cap.

If oil is brought up to the surface, lower pressure causes the gas to release, similar to carbonation bubbles escaping from an open soda bottle. The gas released is what we refer to as associated gas.

Flaring and Venting of Associated Gas

In the early days of oil production, associated gas was seen as a waste. Without systems to transport, capture, or use it, many companies turned to flaring (burning off the gas) or venting (releasing gas directly into the air).

Globally, billions of cubic meters of gas remain burned each year. This wastes precious energy and causes carbon dioxide emissions. Based on the World Bank, gas flaring produces more than 400 million tonnes of CO₂ per year—the equivalent of the annual emissions of more than 70 million automobiles.

Environmental Impact

The environmental impact of poor gas management is significant:

  The emissions of carbon dioxide from flaring accelerate global warming.

  The leaks of methane from vents are more damaging, as methane holds heat 25 times more effectively than CO₂.

  The quality of air in local areas is affected by particulate matter and toxic by-products from incomplete combustion.

Managing gas emissions is essential for mitigating climate change and protecting public health.

Associated Gas Recovery and Utilization Technologies

Instead of wasting gas, energy companies today are investing more in recycling and utilization strategies:

  Reinjection and compression of gas: Associated gas can be compressed and reinjected into reservoirs to maintain pressure, boosting oil recovery while storing gas for later use.

  Conversion into LNG or CNG: Compression or liquefaction allows transportation, enabling gas delivery to distant markets.

  On-site power generation: Mini power plants and distributed energy solutions can convert gas into electricity for oil field operations and local communities.

  Feedstock for petrochemicals: Gas can be used as raw material for hydrogen, methanol, and fertilizers.

These methods not only stop flaring but also create economic value from resources that were previously wasted.

Everyday Residential Uses

In the home, natural gas is used to power cooking appliances, dryers, and water heaters. Usage patterns vary by location: in developed nations, pipelines offer reliable access, while in developing economies, bottled small-scale LNG is more common.

KAITIANGAS: Your Professional Partner for Distributed Natural Gas Recovery

Established in 2002, KAITIANGAS specializes in the recovery and processing of associated gas resources. The company focuses on the development, engineering design, and global promotion of associated gas recovery and liquefaction technologies and equipment. With proprietary intellectual property, mature system solutions, and a professional team, KAITIANGAS has successfully built and operated multiple wellhead LNG recovery projects in China, the Middle East, and Southeast Asia, accumulating extensive field experience and technical advantages.

Conclusion

Associated gas has become an unwelcome byproduct of oil production. It is both a natural energy resource and a climate challenge, as well as a sustainable opportunity. By understanding its definition, formation, environmental impact, and recovery methods, stakeholders can adopt more efficient energy strategies.

The future of associated gas lies in reducing flaring, boosting utilization, and aligning with global climate targets. For businesses, governments, and communities, responsible management of associated gas is an essential step toward cleaner and greener energy solutions.