Fugitive methane gas migration around Alberta's petroleum wells

Abstract

Methane emission quantification from gas migration (GM) and surface casing vent flow (SCVF) is needed to support strategic methane reduction targets and mitigate explosion and groundwater quality risks. This paper assessed which of 451 990 Alberta oil and gas wells should have been (or will be) tested for SCVF and/or GM according to regulations, and compared the results with the provincial GM testing database. As of 2017, GM testing was required on 3.5%, and reported for 0.75%, of Alberta's energy wells. Similarly, SCVF testing was required on 58.2%, and reported for 6.2%, of all wells. An estimated 14.5% of all wells were legally abandoned before GM and SCVF testing regulations existed. All of the remaining wells will require SCVF testing prior to legal abandonment, and an estimated 32.9% to 75.5% of the total will not require GM testing before abandonment based on current regulations. The cumulative number of 'serious' GM reports that have remained open since submission has continuously been increasing each year, which contradicts the requirement for repair within 90 days, suggesting regulations are not enforced. The GM testing procedure is inadequate for quantitative testing. We conclude that fugitive methane emissions, and in particular gas migration, are not well constrained in Alberta.

Orphaned oil and gas well stimulus—Maximizing economic and environmental benefits

“…In addition to how well an abandoned well is plugged, leakage occurrence and rate depend on the integrity of the well (Gasda et al, 2004;King and King, 2013;King and Valencia, 2014;Davies et al, 2014;Lackey et al, 2017;Wisen et al, 2019;Ingraffea et al, 2020;Hammond et al, 2020;Abboud et al, 2020). Surface casing vent flows, surface casing pressures, and gas migration-all indicators of subsurface leakage-at active and unplugged abandoned wells-have been observed at 5.6% of wells in Pennsylvania (Ingraffea et al, 2020), 6.9% of wells in Colorado (Lackey et al, 2017), and 10.8% of wells in British Columbia (Wisen et al, 2019).…”

“…However, identifying attributes linked to higher leakage frequencies has been found to be challenging due to incomplete databases (Montague et al, 2018). Moreover, subsurface gas migration pathways are "rarely clear," and "not all remedial operations will be completely successful" (Abboud et al, 2020).…”

“…In 2018, the industry paid for the plugging of 16,153 wells in the United States that are not orphaned, while state governments paid for the plugging of 2,372 wells (IOGCC, 2019). Government funds to plug orphaned wells are perpetually in shortfall (Ho et al, 2018;Schuwerk and Rogers, 2020;Abboud et al, 2020) and many remain unplugged. The downturn in the oil and gas industry and recent bankruptcies of dozens of companies pose the risk of pushing an increasing number of wells into overloaded government queues (Schuwerk and Rogers, 2020).…”

Reducing oil and gas well leakage: a review of leakage drivers, methane detection and repair options

“…Comprehensive reform, federal governments, inadequate enforcement, leakage testing, legal abandonment, management strategies, methane reduction targets, mitigation strategies, monitoring, policy initiatives, provincial requirements, regulations, state agencies, state regulators, state reporting, testing procedure. Bishop (2013), Ho et al (2016), Alboiu and Walker (2019), Kang et al (2019b) , (Kang et al 2021), Abboud et al (2020), Lavoie et al (2022) Measurements of CH4 emissions Leakage Broken well casing, casing leakage, cement failure, equipment leaks, ethane, fugitive emissions, gaseous emissions, geochemistry, geological formations, high emitters, leak points, leakage pathways, methane plumes, noble gas concentrations, point sources, preferential paths, production-normalized emissions, soil gas methane, surface casing vent flow, thermogenic gas, upstream oil and gas, volatile organic compounds, wellheads. Gasda et al (2004), Miller et al (2013), Davies et al (2014), Kang et al (2014), Pétron et al (2014), Warneke et al (2014), Nathan et al (2015), Zavala-Araiza et al (2015), (Zavala-Araiza et al 2018), Allen (2016), Boothroyd et al (2016), Omara et al (2016), Townsend-Small et al (2016), Atherton et al (2017), Emran et al (2017), Johnson et al (2017), Lavoie et al (2017), Moortgat et al (2018), Pekney et al (2018), Cahill et al (2019), Fox et al (2019), Hoschouer and Townsend-Small (2018), Johnson et al (2019), Pandey et al (2019), Riddick et al (2019), …”

Injecting A Viscoplastic Fluid In A Channel Filled With A Lower Density Newtonian Fluid: Effects Of Premixing

“…Although there is much diversity in the abandonment protocols of the regulatory body across the globe, the goal of the process is to eliminate the potential risks to the environment [2], [6]. Recent studies, however, showed that abandoned wells are leaking Methane [7]- [9]. Improper placement of plugs may be considered as one of the possible reasons for such leaks.…”