Gas release, more specifically known as natural gas release or methane release, is the intentional and controlled release of gases containing alkane hydrocarbons, predominantly methane to the Earth's atmosphere. This method is widely used for the removal of unwanted gases produced during the extraction of coal and crude oil. These gases may be worthless when they cannot be recycled in the production process, do not have an export route to consumer markets, or exceed short-term demand. Even when they have value to the producer, significant quantities can be released during the gas collection, transportation and distribution stages.
Gas ventilation is a major contributor to climate change. [1] [2] Large, concentrated spills are often mitigated with gas flares to produce relatively less harmful carbon dioxide. Routine gas flaring and venting is especially wasteful and could be eliminated in many modern industrial operations, where other low-cost options for using gas are available. [3].
Gas venting should not be confused with similar types of gas release, such as:.
• - Emergency pressure relief as a method of last resort to prevent equipment damage and safeguard life, or fugitive gas emissions, which are unintentional gas leaks that occur in coal, oil and gas operations, such as those from orphan wells.
Gas venting should also not be confused with “gas seepage” from land or oceans, whether natural or due to human activity.
Oilfield Practices Related to Unwanted Gas
The extraction of oil from oil wells, where the acquisition of crude oil is the primary financial objective, is usually accompanied by the extraction of substantial quantities of so-called associated petroleum gas (i.e., a form of crude natural gas). Global statistics from 2012 show that the majority (58%) of this gas was reinjected for storage and to help maintain well pressure, 27% was sent to consumer markets, and the remaining 15% was vented or flared near the well site.[4].
100 million tons of vented associated gas were flared worldwide, equivalent to approximately 3% to 4% of all gas produced from oil and gas wells. [5] The flaring gas produced around 350 million tonnes of greenhouse gas CO equivalent emissions, contributing about 1% of the 33 billion tonnes of carbon dioxide (CO) released by the burning of all fossil fuels.[6] Flaring gas recovery systems (FGRS) are increasingly being deployed as a more economically productive alternative to flaring.[7].
Fugitive emissions
Introduction
Gas release, more specifically known as natural gas release or methane release, is the intentional and controlled release of gases containing alkane hydrocarbons, predominantly methane to the Earth's atmosphere. This method is widely used for the removal of unwanted gases produced during the extraction of coal and crude oil. These gases may be worthless when they cannot be recycled in the production process, do not have an export route to consumer markets, or exceed short-term demand. Even when they have value to the producer, significant quantities can be released during the gas collection, transportation and distribution stages.
Gas ventilation is a major contributor to climate change. [1] [2] Large, concentrated spills are often mitigated with gas flares to produce relatively less harmful carbon dioxide. Routine gas flaring and venting is especially wasteful and could be eliminated in many modern industrial operations, where other low-cost options for using gas are available. [3].
Gas venting should not be confused with similar types of gas release, such as:.
• - Emergency pressure relief as a method of last resort to prevent equipment damage and safeguard life, or fugitive gas emissions, which are unintentional gas leaks that occur in coal, oil and gas operations, such as those from orphan wells.
Gas venting should also not be confused with “gas seepage” from land or oceans, whether natural or due to human activity.
Oilfield Practices Related to Unwanted Gas
The extraction of oil from oil wells, where the acquisition of crude oil is the primary financial objective, is usually accompanied by the extraction of substantial quantities of so-called associated petroleum gas (i.e., a form of crude natural gas). Global statistics from 2012 show that the majority (58%) of this gas was reinjected for storage and to help maintain well pressure, 27% was sent to consumer markets, and the remaining 15% was vented or flared near the well site.[4].
Ideally, at least all unwanted gas would be removed by gas torches, but this has not been achieved in practice. For example, vented volumes from individual wells are sometimes too small and intermittent and may present other difficulties such as high concentrations of contaminants which make flaring more technically and economically challenging. Additionally, gas will continue to emanate from the crude oil for some time after it is moved to storage tanks at the well site and transported elsewhere. This gas may also be directed into a flare, used, or designed to escape without mitigation through vents or pressure regulators. [8].
Global monitoring estimates from the International Energy Agency (IEA) during 2019 indicate that an additional 32 million tonnes of unreduced methane were released from oil extraction, including onshore conventional oil, offshore oil, unconventional oil and downstream oil extraction activities. If the amount released from incomplete gas flaring and fugitive emissions is included, the estimated total is around 37 million tonnes. [9].
Matthew Johnson of the Energy and Emissions Research (EER) Laboratory at Carleton University in Ottawa, Ontario, Canada, said in a December 2023 interview that — contrary to common belief — venting, particularly from heavy oil facilities designed for normal operations, is the primary source of methane emissions in the oil and gas industry. Johnson highlights the urgency of rapidly modernizing oil and gas sites, considering that the associated costs are reasonable, the estimated cost of modernization for the entire industry in Canada is estimated at $3.3 billion between 2027 and 2040 to implement venting and flaring requirements. [10].
Jonson stated that while fossil fuels will not be phased out "overnight," "when it comes to methane emissions, we have a solution and we can implement it right now."*[11] A 2023 report from the Energy and Emissions Research Laboratory analyzes the challenges in meeting the 2030 methane reduction targets under the Global Methane Commitment, due to uncertainties in emissions levels from oil and gas operations. gas. The research, which focuses on Alberta, Canada — the Canadian province with the largest oil and gas industry — presents a 2021 methane inventory that exceeds the official federal inventory by 1.5 times. The study highlights that nearly two-thirds of emissions — originating primarily from uncontrolled tanks, pneumatic equipment and unlit flares — are a result of gas venting — indicating important mitigation opportunities. Notably, methane intensities in Alberta are four times higher than in neighboring British Columbia, highlighting the need for independent monitoring and reporting to ensure the success of emissions reduction initiatives.[11].
Gas venting in the oil and gas industry has gained attention in Alberta, Canada, particularly in light of proposed legislative changes aimed at reducing methane emissions. Federal Environment Minister Steven Guilbeault presented a plan during the 2023 United Nations Climate Change Conference in Dubai "Dubai (City)"), outlining a national emissions cap-and-trade system to reduce emissions without hindering production. The proposed framework aims to limit 2030 emissions to 35 to 38 per cent below 2019 levels, in line with the federal government's goal of achieving net-zero carbon emissions in the sector by 2050. With the oil and gas industry contributing to 28 per cent of Canada's emissions, these proposed changes signal a significant effort to address environmental concerns and combat climate change. [10].
Coal mining and coalfield methane activity
Substantial quantities of methane-rich gas become trapped and adsorbed within coal formations and are inevitably desorbed in association with coal mining. In some cases of underground mining, a formation is permeabilized with perforations before and/or during extraction work and so-called firedamp gases are allowed to vent as a safety measure. In addition, during work, methane enters the air ventilation system in concentrations of up to 1% and is usually freely expelled from the mine mouth. Ventilation air methane (VAM) is the largest source of methane in operating and decommissioned coal mines worldwide. Methane also continues to be desorbed in considerable quantities from stored coal and abandoned mines. [12].
The US Environmental Protection Agency projects that by 2020, global methane releases from coal mines worldwide will exceed 35 million tons or 800 million tons of CO equivalent emissions and will account for 9% of all global methane emissions. China contributes more than 50% of the total, followed by the United States (10%), Russia (7%), Australia, Ukraine, Kazakhstan and India (3-4% each). By 2015, some 200 mines in a wide range of countries had implemented technology to capture around 3 million tonnes of methane, either for economic use or for reduction in gas flares or thermal oxidizers. [12].
Outcrops, veins or near-surface formations are also often permeated by wells to extract and capture methane, in which case it is classified as an unconventional form of gas. [12] This capture of methane in coalfields can reduce the volume of gas seepage that would otherwise occur naturally, while in turn adding carbon dioxide emissions once the fuel is used elsewhere. [12][13].
IEA global monitoring estimates during 2019 suggest that around 40 million tonnes of methane were released from all coal mining-related activities. This amount includes vented, fugitive and leak emissions. [14].
Practices in gas fields and gas pipelines
In gas fields, obtaining non-associated petroleum gas – a form of crude natural gas – represents the main financial objective. Unlike gas extracted from oil fields or coal mines, this type of gas usually has a lower proportion of unwanted components. Most ventilation emissions occur instead during pipeline transport to trade and distribution centers, refineries and consumer markets. [7].
The U.S. Department of Energy reports that the majority of leaks in U.S. gas industry operations in 2017 occurred at compressor stations, from pneumatically operated controllers and regulators.[15] Improved maintenance strategies and advanced equipment technologies exist or are being developed to reduce such venting. [16].
IEA global monitoring estimates indicate that by 2019 around 23 million tonnes of methane were released from all segments of the gas industry, including onshore conventional gas, offshore gas, unconventional gas and downstream gas activities. If the amount released by fugitive emissions is included, the estimated total is approximately 43 million tons. [17].
Historical context
The gases associated with oil and coal mining used to be considered problematic, dangerous and low value, perceived as a 'free' by-product derived from the extraction of coal or liquid hydrocarbons, more financially profitable activities. However, the growth of international gas markets, along with the development of infrastructure and supply chains, has transformed this perception. It is also becoming an increasingly common practice:.
• - Capture and use the associated gas to provide local energy.
• - Reinject recompressed gas for oil reservoir pressure maintenance, secondary recovery and possible subsequent reservoir depressurization once hydrocarbon liquids recovery has been maximized and gas export infrastructure and market access has been established.
In recent years, some industry advocates and policymakers have promoted fossil gas as a 'bridge fuel', arguing that its use generates less waste, and therefore reduces both environmental impact and associated economic losses, during the transition from finite fossil fuels to more sustainable energy sources. [18] However, the actual volumes of methane released cumulatively along the supply chain have an impact on short-term climate warming that already rivals, and may exceed, that of coal and oil use. [19].
Environmental impact
Venting and other releases of gaseous hydrocarbons have increased steadily throughout the industrial era, coupled with rapid growth in fossil fuel production and consumption. [20] The International Energy Agency estimates that total annual methane emissions from the oil and gas industry increased from approximately 63 to 82 million tonnes between 2000 and 2019, an average increase of around 1.4% annually. [21] [22] Globally, the IEA estimates that the geological extraction of coal, crude oil and natural gas is responsible for approximately 20% of all methane emissions. [7] Other researchers have found evidence that their contribution may be substantially greater: 30% or more. [23] [24].
The atmospheric concentration of methane has almost doubled in the last century and is currently 2.5 times higher than in any other period of the last 800,000 years. [25] Methane is a powerful gas that causes global warming despite its lower abundance compared to atmospheric carbon dioxide. Atmospheric methane is responsible for at least a quarter and up to a third of the changes in radiative forcing that drive near-term climate warming. [26] [27] [28].
Natural gas components, such as ethane, propane and butane, have a significantly shorter atmospheric life (one week to two months) compared to methane (one to two decades) and carbon dioxide (one to two centuries). Because of this, they are not dispersed uniformly in the atmosphere and their concentration is considerably lower. [29] However, their oxidation ultimately leads to the creation of longer-lived carbon compounds that also disrupt the atmosphere and the planetary carbon cycle through a variety of complex pathways. [30].
• - Methane emissions.
• - Flare and vent removal systems on PetroWiki.
• - Coal methane at PetroWiki.
References
[1] ↑ Stocker, Thomas (ed.). Climate change 2013 : the physical science basis : Working Group I contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Nueva York. ISBN 978-1-10741-532-4. OCLC 881236891.: https://es.wikipedia.org//books.google.com/books?id=o4gaBQAAQBAJ
[14] ↑ «Methane Tracker - Analysis». International Energy Agency (Paris). 1 de noviembre de 2019. Consultado el 10 de abril de 2020.: https://www.iea.org/reports/methane-tracker
[15] ↑ US EPA, OAR (18 de febrero de 2016). «Methane Emissions from the Oil and Gas Sector». www.epa.gov (en inglés). Consultado el 3 de abril de 2025.: https://www.epa.gov/natural-gas-star-program
[19] ↑ Howarth, R.W. (2014). «Un puente a ninguna parte: las emisiones de metano y la huella de gases de efecto invernadero del gas natural». Energy Science & Engineering (Society of Chemical Industry and John Wiley & Sons Ltd.) 2 (2): 47-60. doi:10.1002/ese3.35.: http://www.eeb.cornell.edu/howarth/publications/Howarth_2014_ESE_methane_emissions.pdf
[20] ↑ Heede, R. (2014). «Tracing anthropogenic carbon dioxide and methane emissions to fossil fuel and cement producers, 1854–2010». Climatic Change 122 (1–2): 229-241. Bibcode:2014ClCh..122..229H. doi:10.1007/s10584-013-0986-y.: http://adsabs.harvard.edu/abs/2014ClCh..122..229H
[29] ↑ Hodnebrog, ∅.; Dalsøren, S.; Myhre, G. (2018), «Lifetimes, direct and indirect radiative forcing, and global warming potentials of ethane (C2H6), propane (C3H8), and butane (C4H10)», Atmos. Sci. Lett., 2018;19:e804 (2): e804, Bibcode:2018AtScL..19E.804H, doi:10.1002/asl.804 .: http://adsabs.harvard.edu/abs/2018AtScL..19E.804H
[30] ↑ Rosado-Reyes, C.; Francisco, J. (2007), «Atmospheric oxidation pathways of propane and its by‐products: Acetone, acetaldehyde, and propionaldehyde», Journal of Geophysical Research 112 (D14310): 1-46, Bibcode:2007JGRD..11214310R, doi:10.1029/2006JD007566 .: http://adsabs.harvard.edu/abs/2007JGRD..11214310R
100 million tons of vented associated gas were flared worldwide, equivalent to approximately 3% to 4% of all gas produced from oil and gas wells. [5] The flaring gas produced around 350 million tonnes of greenhouse gas CO equivalent emissions, contributing about 1% of the 33 billion tonnes of carbon dioxide (CO) released by the burning of all fossil fuels.[6] Flaring gas recovery systems (FGRS) are increasingly being deployed as a more economically productive alternative to flaring.[7].
Ideally, at least all unwanted gas would be removed by gas torches, but this has not been achieved in practice. For example, vented volumes from individual wells are sometimes too small and intermittent and may present other difficulties such as high concentrations of contaminants which make flaring more technically and economically challenging. Additionally, gas will continue to emanate from the crude oil for some time after it is moved to storage tanks at the well site and transported elsewhere. This gas may also be directed into a flare, used, or designed to escape without mitigation through vents or pressure regulators. [8].
Global monitoring estimates from the International Energy Agency (IEA) during 2019 indicate that an additional 32 million tonnes of unreduced methane were released from oil extraction, including onshore conventional oil, offshore oil, unconventional oil and downstream oil extraction activities. If the amount released from incomplete gas flaring and fugitive emissions is included, the estimated total is around 37 million tonnes. [9].
Matthew Johnson of the Energy and Emissions Research (EER) Laboratory at Carleton University in Ottawa, Ontario, Canada, said in a December 2023 interview that — contrary to common belief — venting, particularly from heavy oil facilities designed for normal operations, is the primary source of methane emissions in the oil and gas industry. Johnson highlights the urgency of rapidly modernizing oil and gas sites, considering that the associated costs are reasonable, the estimated cost of modernization for the entire industry in Canada is estimated at $3.3 billion between 2027 and 2040 to implement venting and flaring requirements. [10].
Jonson stated that while fossil fuels will not be phased out "overnight," "when it comes to methane emissions, we have a solution and we can implement it right now."*[11] A 2023 report from the Energy and Emissions Research Laboratory analyzes the challenges in meeting the 2030 methane reduction targets under the Global Methane Commitment, due to uncertainties in emissions levels from oil and gas operations. gas. The research, which focuses on Alberta, Canada — the Canadian province with the largest oil and gas industry — presents a 2021 methane inventory that exceeds the official federal inventory by 1.5 times. The study highlights that nearly two-thirds of emissions — originating primarily from uncontrolled tanks, pneumatic equipment and unlit flares — are a result of gas venting — indicating important mitigation opportunities. Notably, methane intensities in Alberta are four times higher than in neighboring British Columbia, highlighting the need for independent monitoring and reporting to ensure the success of emissions reduction initiatives.[11].
Gas venting in the oil and gas industry has gained attention in Alberta, Canada, particularly in light of proposed legislative changes aimed at reducing methane emissions. Federal Environment Minister Steven Guilbeault presented a plan during the 2023 United Nations Climate Change Conference in Dubai "Dubai (City)"), outlining a national emissions cap-and-trade system to reduce emissions without hindering production. The proposed framework aims to limit 2030 emissions to 35 to 38 per cent below 2019 levels, in line with the federal government's goal of achieving net-zero carbon emissions in the sector by 2050. With the oil and gas industry contributing to 28 per cent of Canada's emissions, these proposed changes signal a significant effort to address environmental concerns and combat climate change. [10].
Coal mining and coalfield methane activity
Substantial quantities of methane-rich gas become trapped and adsorbed within coal formations and are inevitably desorbed in association with coal mining. In some cases of underground mining, a formation is permeabilized with perforations before and/or during extraction work and so-called firedamp gases are allowed to vent as a safety measure. In addition, during work, methane enters the air ventilation system in concentrations of up to 1% and is usually freely expelled from the mine mouth. Ventilation air methane (VAM) is the largest source of methane in operating and decommissioned coal mines worldwide. Methane also continues to be desorbed in considerable quantities from stored coal and abandoned mines. [12].
The US Environmental Protection Agency projects that by 2020, global methane releases from coal mines worldwide will exceed 35 million tons or 800 million tons of CO equivalent emissions and will account for 9% of all global methane emissions. China contributes more than 50% of the total, followed by the United States (10%), Russia (7%), Australia, Ukraine, Kazakhstan and India (3-4% each). By 2015, some 200 mines in a wide range of countries had implemented technology to capture around 3 million tonnes of methane, either for economic use or for reduction in gas flares or thermal oxidizers. [12].
Outcrops, veins or near-surface formations are also often permeated by wells to extract and capture methane, in which case it is classified as an unconventional form of gas. [12] This capture of methane in coalfields can reduce the volume of gas seepage that would otherwise occur naturally, while in turn adding carbon dioxide emissions once the fuel is used elsewhere. [12][13].
IEA global monitoring estimates during 2019 suggest that around 40 million tonnes of methane were released from all coal mining-related activities. This amount includes vented, fugitive and leak emissions. [14].
Practices in gas fields and gas pipelines
In gas fields, obtaining non-associated petroleum gas – a form of crude natural gas – represents the main financial objective. Unlike gas extracted from oil fields or coal mines, this type of gas usually has a lower proportion of unwanted components. Most ventilation emissions occur instead during pipeline transport to trade and distribution centers, refineries and consumer markets. [7].
The U.S. Department of Energy reports that the majority of leaks in U.S. gas industry operations in 2017 occurred at compressor stations, from pneumatically operated controllers and regulators.[15] Improved maintenance strategies and advanced equipment technologies exist or are being developed to reduce such venting. [16].
IEA global monitoring estimates indicate that by 2019 around 23 million tonnes of methane were released from all segments of the gas industry, including onshore conventional gas, offshore gas, unconventional gas and downstream gas activities. If the amount released by fugitive emissions is included, the estimated total is approximately 43 million tons. [17].
Historical context
The gases associated with oil and coal mining used to be considered problematic, dangerous and low value, perceived as a 'free' by-product derived from the extraction of coal or liquid hydrocarbons, more financially profitable activities. However, the growth of international gas markets, along with the development of infrastructure and supply chains, has transformed this perception. It is also becoming an increasingly common practice:.
• - Capture and use the associated gas to provide local energy.
• - Reinject recompressed gas for oil reservoir pressure maintenance, secondary recovery and possible subsequent reservoir depressurization once hydrocarbon liquids recovery has been maximized and gas export infrastructure and market access has been established.
In recent years, some industry advocates and policymakers have promoted fossil gas as a 'bridge fuel', arguing that its use generates less waste, and therefore reduces both environmental impact and associated economic losses, during the transition from finite fossil fuels to more sustainable energy sources. [18] However, the actual volumes of methane released cumulatively along the supply chain have an impact on short-term climate warming that already rivals, and may exceed, that of coal and oil use. [19].
Environmental impact
Venting and other releases of gaseous hydrocarbons have increased steadily throughout the industrial era, coupled with rapid growth in fossil fuel production and consumption. [20] The International Energy Agency estimates that total annual methane emissions from the oil and gas industry increased from approximately 63 to 82 million tonnes between 2000 and 2019, an average increase of around 1.4% annually. [21] [22] Globally, the IEA estimates that the geological extraction of coal, crude oil and natural gas is responsible for approximately 20% of all methane emissions. [7] Other researchers have found evidence that their contribution may be substantially greater: 30% or more. [23] [24].
The atmospheric concentration of methane has almost doubled in the last century and is currently 2.5 times higher than in any other period of the last 800,000 years. [25] Methane is a powerful gas that causes global warming despite its lower abundance compared to atmospheric carbon dioxide. Atmospheric methane is responsible for at least a quarter and up to a third of the changes in radiative forcing that drive near-term climate warming. [26] [27] [28].
Natural gas components, such as ethane, propane and butane, have a significantly shorter atmospheric life (one week to two months) compared to methane (one to two decades) and carbon dioxide (one to two centuries). Because of this, they are not dispersed uniformly in the atmosphere and their concentration is considerably lower. [29] However, their oxidation ultimately leads to the creation of longer-lived carbon compounds that also disrupt the atmosphere and the planetary carbon cycle through a variety of complex pathways. [30].
• - Methane emissions.
• - Flare and vent removal systems on PetroWiki.
• - Coal methane at PetroWiki.
References
[1] ↑ Stocker, Thomas (ed.). Climate change 2013 : the physical science basis : Working Group I contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Nueva York. ISBN 978-1-10741-532-4. OCLC 881236891.: https://es.wikipedia.org//books.google.com/books?id=o4gaBQAAQBAJ
[14] ↑ «Methane Tracker - Analysis». International Energy Agency (Paris). 1 de noviembre de 2019. Consultado el 10 de abril de 2020.: https://www.iea.org/reports/methane-tracker
[15] ↑ US EPA, OAR (18 de febrero de 2016). «Methane Emissions from the Oil and Gas Sector». www.epa.gov (en inglés). Consultado el 3 de abril de 2025.: https://www.epa.gov/natural-gas-star-program
[19] ↑ Howarth, R.W. (2014). «Un puente a ninguna parte: las emisiones de metano y la huella de gases de efecto invernadero del gas natural». Energy Science & Engineering (Society of Chemical Industry and John Wiley & Sons Ltd.) 2 (2): 47-60. doi:10.1002/ese3.35.: http://www.eeb.cornell.edu/howarth/publications/Howarth_2014_ESE_methane_emissions.pdf
[20] ↑ Heede, R. (2014). «Tracing anthropogenic carbon dioxide and methane emissions to fossil fuel and cement producers, 1854–2010». Climatic Change 122 (1–2): 229-241. Bibcode:2014ClCh..122..229H. doi:10.1007/s10584-013-0986-y.: http://adsabs.harvard.edu/abs/2014ClCh..122..229H
[29] ↑ Hodnebrog, ∅.; Dalsøren, S.; Myhre, G. (2018), «Lifetimes, direct and indirect radiative forcing, and global warming potentials of ethane (C2H6), propane (C3H8), and butane (C4H10)», Atmos. Sci. Lett., 2018;19:e804 (2): e804, Bibcode:2018AtScL..19E.804H, doi:10.1002/asl.804 .: http://adsabs.harvard.edu/abs/2018AtScL..19E.804H
[30] ↑ Rosado-Reyes, C.; Francisco, J. (2007), «Atmospheric oxidation pathways of propane and its by‐products: Acetone, acetaldehyde, and propionaldehyde», Journal of Geophysical Research 112 (D14310): 1-46, Bibcode:2007JGRD..11214310R, doi:10.1029/2006JD007566 .: http://adsabs.harvard.edu/abs/2007JGRD..11214310R