{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T02:06:49Z","timestamp":1773799609404,"version":"3.50.1"},"reference-count":26,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2023,11,17]],"date-time":"2023-11-17T00:00:00Z","timestamp":1700179200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"METEC Industry Advisory Board (IAB) at Colorado State University"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The recent interest in measuring methane (CH4) emissions from abandoned oil and gas wells has resulted in five methods being typically used. In line with the US Federal Orphaned Wells Program\u2019s (FOWP) guidelines and the American Carbon Registry\u2019s (ACR) protocols, quantification methods must be able to measure minimum emissions of 1 g of CH4 h\u22121 to within \u00b120%. To investigate if the methods meet the required standard, dynamic chambers, a Hi-Flow (HF) sampler, and a Gaussian plume (GP)-based approach were all used to quantify a controlled emission (Qav; g h\u22121) of 1 g of CH4 h\u22121. After triplicate experiments, the average accuracy (Ar; %) and the upper (Uu; %) and lower (Ul; %) uncertainty bounds of all methods were calculated. Two dynamic chambers were used, one following the ACR guidelines, and a second \u201cmobile\u201d chamber made from lightweight materials that could be constructed around a source of emission on a well head. The average emission calculated from the measurements made using the dynamic chamber (Qav = 1.01 g CH4 h\u22121, Ar = +0.9%), the mobile chamber (Qav = 0.99 g CH4 h\u22121, Ar = \u22121.4%), the GP approach (Qav = 0.97 g CH4 h\u22121, Ar = \u22122.6%), and the HF sampler (Qav = 1.02 g CH4 h\u22121, Ar = +2.2%) were all within \u00b13% of 1 g of CH4 h\u22121 and met the requirements of the FOWP and ACR protocols. The results also suggest that the individual measurements made using the dynamic chamber can quantify emissions of 1 g of CH4 h\u22121 to within \u00b16% irrespective of the design (material, number of parts, geometrical shape, and hose length), and changes to the construction or material specifications as defined via ACR make no discernible difference to the quantification uncertainty. Our tests show that a collapsible chamber can be easily constructed around the emission source on an abandoned well and be used to quantify emissions from abandoned wells in remote areas. To our knowledge, this is the first time that methods for measuring the CH4 emissions of 1 g of CH4 h\u22121 have been quantitively assessed against a known reference source and against each other.<\/jats:p>","DOI":"10.3390\/s23229246","type":"journal-article","created":{"date-parts":[[2023,11,17]],"date-time":"2023-11-17T09:23:43Z","timestamp":1700213023000},"page":"9246","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Uncertainty Quantification of Methods Used to Measure Methane Emissions of 1 g CH4 h\u22121"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1684-1843","authenticated-orcid":false,"given":"Stuart N.","family":"Riddick","sequence":"first","affiliation":[{"name":"Energy Institute, Colorado State University, Fort Collins, CO 80524, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2229-4946","authenticated-orcid":false,"given":"Mercy","family":"Mbua","sequence":"additional","affiliation":[{"name":"Energy Institute, Colorado State University, Fort Collins, CO 80524, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John C.","family":"Riddick","sequence":"additional","affiliation":[{"name":"Independent Researcher, Lockerbie DG11 2DU, Scotland, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cade","family":"Houlihan","sequence":"additional","affiliation":[{"name":"Energy Institute, Colorado State University, Fort Collins, CO 80524, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anna L.","family":"Hodshire","sequence":"additional","affiliation":[{"name":"Energy Institute, Colorado State University, Fort Collins, CO 80524, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel J.","family":"Zimmerle","sequence":"additional","affiliation":[{"name":"Energy Institute, Colorado State University, Fort Collins, CO 80524, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,17]]},"reference":[{"key":"ref_1","unstructured":"IPCC (2014). Climate Change 2013\u2014The Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press."},{"key":"ref_2","unstructured":"EPA (2022, October 26). Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990\u20132020: Updates Under Consideration for Abandoned Oil and Gas Wells, Available online: https:\/\/www.epa.gov\/system\/files\/documents\/2021-09\/2022-ghgi-update-abandoned-wells_sept-2021.pdf."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2283","DOI":"10.1002\/2015GL067623","article-title":"Emissions of coalbed and natural gas methane from abandoned oil and gas wells in the United States","volume":"43","author":"Ferrara","year":"2016","journal-title":"Geophys. Res. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1849","DOI":"10.1016\/j.scitotenv.2018.10.082","article-title":"Measuring methane emissions from abandoned and active oil and gas wells in West Virginia","volume":"651","author":"Riddick","year":"2019","journal-title":"Sci. Total Environ."},{"key":"ref_5","unstructured":"Department of Interior (2023, May 05). Assessing Methane Emissions from Orphaned Wells to Meet Reporting Requirements of the 2021 Infrastructure Investment and Jobs Act (BIL): Federal Program Guidelines, Available online: https:\/\/www.doi.gov\/sites\/doi.gov\/files\/federal-orphaned-wells-methane-measurement-guidelines-final-for-posting-v2.pdf."},{"key":"ref_6","unstructured":"EPA (2023, May 05). Environmental Protection Agency-Method 21-Determination of Volatile Organic Compound Leaks, Available online: https:\/\/www.epa.gov\/sites\/default\/files\/2017-08\/documents\/method_21.pdf."},{"key":"ref_7","unstructured":"ACR (2023, May 05). American Carbon Registry\u2014Methodology for the Quantification, Monitoring, Reporting and Verification of Greenhouse Gas Emissions Reductions from Plugging Abandoned and Orphaned Oil and Gas Wells. Available online: https:\/\/americancarbonregistry.org\/carbon-accounting\/standards-methodologies\/plugging-abandoned-orphaned-oil-and-gas-wells\/1-0-acr_aoog_peer_review_04272022.pdf."},{"key":"ref_8","unstructured":"Matson, P.A., and Harris, R.C. (1995). Biogenic Trace Gases: Measuring Emissions from Soil and Water, Blackwell Science Ltd."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"103116","DOI":"10.1016\/j.ijggc.2020.103116","article-title":"Variability observed over time in methane emissions from abandoned oil and gas wells","volume":"100","author":"Riddick","year":"2020","journal-title":"Int. J. Greenh. Gas Control."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Barnes, I., and Rudzinski, K.J. (2006). Environmental Simulation Chambers: Application to Atmospheric Chemical Processes, Springer.","DOI":"10.1007\/1-4020-4232-9"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1080\/17583004.2018.1443642","article-title":"Measurement of methane emissions from abandoned oil and gas wells in Hillman State Park, Pennsylvania","volume":"9","author":"Pekney","year":"2018","journal-title":"Carbon Manag."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"17768","DOI":"10.1073\/pnas.1304880110","article-title":"Measurements of methane emissions at natural gas production sites in the United States","volume":"110","author":"Allen","year":"2013","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1072","DOI":"10.1080\/10962247.2015.1056888","article-title":"Assessment of volatile organic compound and hazardous air pollutant emissions from oil and natural gas well pads using mobile remote and on-site direct measurements","volume":"65","author":"Brantley","year":"2015","journal-title":"J. Air Waste Manag. Assoc."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"011003","DOI":"10.1088\/2515-7620\/ab01f2","article-title":"Methane emissions from conventional and unconventional oil and gas production sites in southeastern Saskatchewan","volume":"1","author":"Baillie","year":"2019","journal-title":"Canada. Environ. Res. Commun."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"6237","DOI":"10.1073\/pnas.1316546111","article-title":"Toward a better understanding and quantification of methane emissions from shale gas development","volume":"111","author":"Caulton","year":"2014","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1007\/s11104-008-9599-z","article-title":"Approaches to measuring fluxes of methane and nitrous oxide between landscapes and the atmosphere","volume":"309","author":"Denmead","year":"2008","journal-title":"Plant Soil"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1320","DOI":"10.1175\/1520-0450(1995)034<1320:BTLSDM>2.0.CO;2","article-title":"Backward-Time Lagrangian Stochastic Dispersion Models and Their Application to Estimate Gaseous Emissions","volume":"34","author":"Flesch","year":"1995","journal-title":"J. Appl. Meteorol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e2020GL089663","DOI":"10.1029\/2020GL089663","article-title":"An Analysis of Abandoned Oil Well Characteristics Affecting Methane Emissions Estimates in the Cherokee Platform in Eastern Oklahoma","volume":"47","author":"Reeder","year":"2020","journal-title":"Geophys. Res. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1080\/10962247.2020.1735576","article-title":"Understanding oil and gas pneumatic controllers in the Denver\u2013Julesburg basin using optical gas imaging","volume":"70","author":"Stovern","year":"2020","journal-title":"J. Air Waste Manag. Assoc."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"11506","DOI":"10.1021\/acs.est.0c01285","article-title":"Detection Limits of Optical Gas Imaging for Natural Gas Leak Detection in Realistic Controlled Conditions","volume":"54","author":"Zimmerle","year":"2020","journal-title":"Environ. Sci. Technol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"000111","DOI":"10.1525\/elementa.2021.000111","article-title":"Methane and ethane emission quantifications from onshore oil and gas sites in Romania, using a tracer gas dispersion method","volume":"10","author":"Delre","year":"2022","journal-title":"Elem. Sci. Anthr."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"12234","DOI":"10.1021\/acs.est.3c00229","article-title":"Extension of Methane Emission Rate Distribution for Permian Basin Oil and Gas Production Infrastructure by Aerial LiDAR","volume":"57","author":"Kunkel","year":"2023","journal-title":"Environ. Sci. Technol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1039\/D1EA00046B","article-title":"Methane detection and quantification in the upstream oil and gas sector: The role of satellites in emissions detection, reconciling and reporting","volume":"2","author":"Cooper","year":"2022","journal-title":"Environ. Sci. Atmos."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"6285","DOI":"10.5194\/amt-15-6285-2022","article-title":"A quantitative comparison of methods used to measure smaller methane emissions typically observed from superannuated oil and gas infrastructure","volume":"15","author":"Riddick","year":"2022","journal-title":"Atmos. Meas. Tech."},{"key":"ref_25","unstructured":"(2023, November 16). Heath, \u201cSEMTECH\u00ae HI-FLOW 2\u201d. Available online: https:\/\/heathus.com\/wp-content\/uploads\/2023\/08\/HI-FLOW-2.pdf."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"18173","DOI":"10.1073\/pnas.1408315111","article-title":"Direct measurements of methane emissions from abandoned oil and gas wells in Pennsylvania","volume":"111","author":"Kang","year":"2014","journal-title":"Proc. Natl. Acad. Sci. USA"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/22\/9246\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:24:48Z","timestamp":1760131488000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/22\/9246"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,11,17]]},"references-count":26,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2023,11]]}},"alternative-id":["s23229246"],"URL":"https:\/\/doi.org\/10.3390\/s23229246","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,11,17]]}}}