Fugitive gas emissions

Fugitive gas emissions are emissions of gas (typically natural gas, which contains methane) to atmosphere or groundwater[1] which result from oil and gas or coal mining activity.[2] In 2016, these emissions, when converted to their equivalent impact of carbon dioxide, accounted for 5.8% of all global greenhouse gas emissions.[2]

Most fugitive emissions are the result of loss of well integrity through poorly sealed well casings due to geochemically unstable cement.[3] This allows gas to escape through the well itself (known as surface casing vent flow) or via lateral migration along adjacent geological formations (known as gas migration).[3] Approximately 1-3% of methane leakage cases in unconventional oil and gas wells are caused by imperfect seals and deteriorating cement in wellbores.[3] Some leaks are also the result of leaks in equipment, intentional pressure release practices, or accidental releases during normal transportation, storage, and distribution activities.[4][5][6]

Emissions can be measured using either ground-based or airborne techniques.[3][4][7] In Canada, the oil and gas industry is thought to be the largest source of greenhouse gas and methane emissions,[8] and approximately 40% of Canada's emissions originate from Alberta.[5] Emissions are largely self-reported by companies. The Alberta Energy Regulator keeps a database on wells releasing fugitive gas emissions in Alberta,[9] and the British Columbia Oil and Gas Commission keeps a database of leaky wells in British Columbia. Testing wells at the time of drilling was not required in British Columbia until 2010, and since then 19% of new wells have reported leakage problems. This number may be a low estimate, as suggested by fieldwork completed by the David Suzuki Foundation.[1] Some studies have shown a range of 6-30% of wells suffer gas leakage.[7][9][10][11]

Canada and Alberta have plans for policies to reduce emissions, which may help combat climate change.[12][13] Costs related to reducing emissions are very location-dependent and can vary widely.[14] Methane has a greater global warming impact than carbon dioxide, as its radiative force is 120, 86 and 34 times that of carbon dioxide, when considering a 1, 20 and 100 year time frame (including Climate Carbon Feedback [15] [16][9] Additionally, it leads to increases in carbon dioxide concentration through its oxidation by water vapor.[17]

  1. ^ a b Wisen, Joshua; Chesnaux, Romain; Werring, John; Wendling, Gilles; Baudron, Paul; Barbecot, Florent (2017-10-01). "A Portrait of Oil and Gas Wellbore Leakage in Northeastern British Columbia, Canada". GeoOttawa2017.
  2. ^ a b Ritchie, Hannah; Roser, Max (11 May 2020). "Emissions by sector". Our World in Data. Retrieved 30 July 2021.
  3. ^ a b c d Cahill, Aaron G.; Steelman, Colby M.; Forde, Olenka; Kuloyo, Olukayode; Ruff, S. Emil; Mayer, Bernhard; Mayer, K. Ulrich; Strous, Marc; Ryan, M. Cathryn (27 March 2017). "Mobility and persistence of methane in groundwater in a controlled-release field experiment". Nature Geoscience. 10 (4): 289–294. Bibcode:2017NatGe..10..289C. doi:10.1038/ngeo2919. hdl:1880/115891. ISSN 1752-0908.
  4. ^ a b Cite error: The named reference :4 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference :6 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference :7 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference :3 was invoked but never defined (see the help page).
  8. ^ Johnson, Matthew R.; Tyner, David R.; Conley, Stephen; Schwietzke, Stefan; Zavala-Araiza, Daniel (2017-11-07). "Comparisons of Airborne Measurements and Inventory Estimates of Methane Emissions in the Alberta Upstream Oil and Gas Sector". Environmental Science & Technology. 51 (21): 13008–13017. Bibcode:2017EnST...5113008J. doi:10.1021/acs.est.7b03525. ISSN 0013-936X. PMID 29039181.
  9. ^ a b c Bachu, Stefan (2017). "Analysis of gas leakage occurrence along wells in Alberta, Canada, from a GHG perspective – Gas migration outside well casing". International Journal of Greenhouse Gas Control. 61: 146–154. doi:10.1016/j.ijggc.2017.04.003.
  10. ^ Boothroyd, I.M.; Almond, S.; Qassim, S.M.; Worrall, F.; Davies, R.J. (March 2016). "Fugitive emissions of methane from abandoned, decommissioned oil and gas wells". Science of the Total Environment. 547: 461–469. Bibcode:2016ScTEn.547..461B. doi:10.1016/j.scitotenv.2015.12.096. PMID 26822472.
  11. ^ A. Ingraffea, R. Santoro, S. B. Shonkoff, Wellbore Integrity: Failure Mechanisms, Historical Record, and Rate Analysis. EPA’s Study Hydraul. Fract. Its Potential Impact Drink. Water Resour. 2013 Tech. Work. Present. Well Constr. Subsurf. Model. (2013) (available at http://www2.epa.gov/hfstudy/2013-technical-workshop-presentations-0 )
  12. ^ Cite error: The named reference :8 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference :9 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference :10 was invoked but never defined (see the help page).
  15. ^ Myhre, G.; Shindell, D.; Bréon, F.-M.; Collins, W.; et al. (2013). "Chapter 8: Anthropogenic and Natural Radiative Forcing" (PDF). IPCC AR5 WG1 2013. pp. 659–740.
  16. ^ Etminan, M.; Myhre, G.; Highwood, E. J.; Shine, K. P. (2016-12-28). "Radiative forcing of carbon dioxide, methane, and nitrous oxide: A significant revision of the methane radiative forcing". Geophysical Research Letters. 43 (24): 2016GL071930. Bibcode:2016GeoRL..4312614E. doi:10.1002/2016GL071930. ISSN 1944-8007.
  17. ^ Myhre; Shindell; Bréon; Collins; Fuglestvedt; Huang; Koch; Lamarque; Lee; Mendoza; Nakajima; Robock; Stephens; Takemura; Zhang (2013). "Anthropogenic and Natural Radiative Forcing". In Stocker; Qin; Plattner; Tignor; Allen; Boschung; Nauels; Xia; Bex; Midgley (eds.). Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press.