Topic last reviewed: 10 April 2013
Sectors: Downstream, Midstream, Upstream
Flaring can occur in the oil and gas industry for many reasons, ranging from initial start-up testing of a facility to unplanned equipment malfunctions. Generally, flaring can be classified in the following categories for the purpose of defining techniques for flare reduction:
- Initial start-up flaring occurs during the commissioning and initial start-up phases of a plant or process unit, when gas and liquids are introduced into new facilities and equipment to test the production of the products for sale (oil, gas, LPG, condensate, etc.).
- Continuous production flaring occurs after initial start-up, when the plant or process unit is in production. Continuous production flaring is characterized by a routine, continuous gas stream which is routed to a flare system because there is no economical gas valorization route for a satellite field or for the routine venting of flash gas in upstream production.
- Operational /non-continuous production flaring may occur on a planned or unplanned basis for a number of reasons.Planned non-continuous production flaring may occur, for example, due to scheduled maintenance, equipment shutdowns, well completions, workovers and liquids unloading, etc. Unplanned non-continuous production flaring may be caused, for example, by mechanical equipment failures, instrument failures, and difficulty restarting well production.
The following table presents some common causes for each category of flaring. The determination of the cause of a flaring event is important to allow identification and evaluation of flare reduction alternatives, e.g. modification projects to reduce continuous or planned non-continuous production flaring, and clear procedures to avoid future unplanned non-continuous flaring events.
Flaring categories
Category | Cause | Description |
Initial start-up flaring | - | During the first weeks or months of the plant life, some of the associated gas may be flared before all the gas compressors are commissioned, or for reservoir management reasons. |
Continuous production flaring (mainly older sites) | Well with low gas-to-oil ratio (GOR) | Gas is flared because it is not economical to recover the gas. |
Gas Utilization Infeasible | Lack of local gas market, remoteness from international markets, lack of gas gathering and compression infrastructure. | |
Gas release to flare | Gas and liquid are released continuously from the process to flare (e.g. glycol flash drum, glycol gas stripping, compressor seals, storage tanks etc.). | |
Planned operational flaring | Maintenance and inspection |
|
Modifications and construction |
| |
Reservoir and well maintenance |
| |
Safety and production operations |
| |
Drilling and workovers |
| |
Unplanned operational flaring | Production dynamics |
|
Mechanical failures in machines | Rotating and alternating equipment (pumps, compressors, turbines, etc.) | |
Instrument and valve failures |
| |
Wells |
| |
Other |
| |
Safety flaring | Flaring to purge flare lines with hydrocarbon gas, for safety purposes. Includes emergency shutdown with depressurization. |
Technology maturity
| Commercially available?: | No |
| Offshore viability: | No |
| Brownfield retrofit?: | No |
| Years experience in the industry: | <5 |
Additional notes:
NB: Technology Maturity section is N/A - this document is classification of flaring types only.
References:
- Labeyrie, H. and Rocher, A. (2010). ‘Reducing Flaring and Improving Energy Efficiency: An Operator’s View’. Society of Professional Engineers (SPE) Paper 126644.
- World Bank (2004). ‘Global Gas Flaring Reduction, A Public-Private Partnership: A voluntary standard for global gas flaring and venting reduction’. Report Number 4, World Bank Group, May 2004. (Publication reference 29555.)