Methane Emissions

What causes methane emissions in upstream oil and gas production facilities? If you have ever had this question, read on.

Types of Emissions

Fugitive Emissions are methane emissions from unintentional or accidental releases. For example, methane emissions from a leak at a flange or threaded connections between pipes and fittings or pipes and vessels.

Incomplete Combustion or Methane Slip refers to methane that is released into the atmosphere due to incomplete combustion. For example, methane that is not completely burned during flaring or combustion in an engine.

Venting is the intentional release of methane into the atmosphere. For example, methane emissions due to blowdown of equipment such as pipelines, the operation of natural gas driven pneumatic devices, or the relief of pressure during emergencies.

What is being done to reduce methane emissions?

As of March 12, 2024, 134 member companies in more than 70 countries have joined the Oil and Gas Methane Parnership 2.0, the flagship oil and gas reporting and mitigation program of the UN Environment Programme . Non-company members include the European Commission , Environmental Defense Fund , Climate & Clean Air Coalition , and Clean Air Task Force .

Fugitive Emissions

The objectives of a Leak Detection and Repair (LDAR) program include detection of methane leaks, repair of leaks as quickly as possible, and identification of components that persistently leak. Multiple layers of detection technology, a system of systems is being deployed to quickly detect leaks.

• Optical Gas Imaging (OGI) Cameras (portable and permanently mounted)
• Continuous methane monitoring sensors ( ChampionX Emissions Technologies SOOFIE)
• Flyovers using airplane ( Bridger Photonics, Inc. ), helicopter, stratospheric balloon ( Aerostar (Aerostar International LLC) ) and drone mounted methane detectors
• Methane detecting satellites (constellation of 24 satellites to be deployed over three years SCEPTER )
• Data analytics and machine learning (processing and aggregation of data from a multilayered system of methane emission detection technologies Amazon Web Services (AWS) )
• Centralized operations and emissions tracking center (for exmaple

Solutions to reduce or eliminate fugitive emissions include:

• Increased inspection and maintenance of persistant leak sources
• Elimination or replacement of persistant leak sources with superior equipment
• Modular design and elimination of equipment as production declines
• Use of welded connections instead of threaded connections and flanges
• Use of higher pressure rated vessels instead of tanks

Incomplete Combustion or Methane Slip

Solutions to eliminate incomplete combustion or methane slip include:

• Elimination or reduction of routine flaring
• Replacement of natural gas fired engines with electrically driven motors
• Automating air to fuel ratio controllers on flares, combustors, and natural gas fired equipment
• Electrification of natural gas fired heating equipment

Venting from Processing Equipment

Oil and natural gas wells produce a combination of oil, natural gas, and produced water. Once brought to the surface, each of these three phases of production is separated by processing equipment using techniques such as gravity separation and pressure drops. Solutions to prevent venting from the processing equipment include:

• Vapor recovery units (VRUs) to compress flash gas off of low pressure tanks and vessels and inject it into natural gas sales line
• Use of gas recovery systems, relief to lower pressure system, or combustion instead of blowdown to atmosphere to reduce the pressure in pipelines or equipment during maintenance activities ( ZEVAC )
• Routine replacement of compressor rod packing, use of dry seals, and recovery or combustion of released natural gas
• Curtailment of production when natural gas sales pipeline capacity is unavailable
• If venting cannot be eliminated, combustion of natural gas and ensuring flare and combustor pilots are lit at all times so that gas routed to the flare or combustor is burned (carbon dioxide is a less harmful greenhouse gas than methane)

Venting from natural gas driven Pneumatic Devices

Pneumatic devices operate through the release of pressure from a high pressure source to the atmosphere. Venting from pneumatic devices occurs when the high pressure source is produced natural gas. Solutions to reduce or eliminate methane emissions from gas-driven pneumatic devices include:

• Replacing high-bleed natural gas driven pneumatic devices with low-bleed equivalents (reduction in methane emissions)
• Conversion of natural gas driven regulators from vent to non-venting operation ( Kimray, Inc conversion kit)
• Eliminating natural gas venting from pneumatic devices through the use of compressed air ( Tegre Corporation ) or nitrogen ( Kathairos Solutions ) as the driving gas for pneumatic devices or replacement of pneumatic devices with electrically acuated devices

Keep the conversation going

If there is anything I haven't covered or you find unclear, let me know in the comments. Please share with any of your contacts who would benefit.

Views expressed are my own.

#naturalgas #oilandgas #flaring #emissionreduction #ghgemissions #pipelines #methane