What is it?
Where there’s oil, there’s gas, usually in large quantities. This associated gas (AG) is released when oil reservoirs are drilled and throughout oil extraction.
Flaring is the controlled burning of AG; venting is the controlled release of unburned gases directly to the atmosphere.
Why Does Flaring and Venting Happen?
Most AG is re-injected back into the well; this can help to force out more oil. Having the facility to flare and vent AG is important in keeping wells safe during shut downs and emergencies.
The decision to vent or flare will depend on local conditions and the nature of the gas. Flaring reduces methane emissions but venting may be preferred if the water content of the gas is high. Venting reduces noise and particulate pollution near the well but it is not feasible if the gas mixture is too toxic.
Where wells produce large amounts of AG and/or re-injection is not straightforward, the gas must be released in order to operate the well safely. Oil companies often state that they have limited options for using AG locally especially in remote locations. If it is not economically feasible to build infrastructure to capture, store and transport the gas or to process it to make liquefied natural gas (LNG), then flaring/venting is seen as the only viable option.
According to the Gas Flaring Reduction Partnership supported by the World Bank, oil companies and others, developing countries face particular barriers to reducing gas flaring, including:
- Limited access to international gas markets as well as local markets
- A lack of finance to put the necessary infrastructure in place
- Ineffective regulatory frameworks
Flaring and Fracking
Flaring and venting of AG is also associated with the recently developed process of hydraulic fracturing – or fracking – used in the extraction of natural gas and oil (known as ‘tight oil’) from dense shale rock. This has contributed to an increase in flaring and venting in some regions of the world, notably in the USA where it has contributed to the country becoming one of the largest contributors of flaring with a 2.5% increase in gas volume from 2010 to 2011, mostly associated with developments in the Bakken Oil Field, North Dakota.