270-3 Analyzing Methane Emission Measurements and Regional Variations from 1,445 Orphan Wells Across the United States

Session: Carbon Dioxide Storage and Mitigation of Greenhouse Gas Emissions (Posters)

Poster Booth No.: 225

Presenting Author:

Rand Gardner

Authors:

Gardner, Rand¹, Gianoutsos, Nicholas², Haase, Karl B.³, Wiens, Ashton⁴, Merrill, Matthew Davis⁵, Lei, Uei⁶, Woda, Joshua⁷

(1) US Geological Survey, Denver, CO, USA, (2) US Geological Survey, Denver, CO, USA, (3) US Geological Survey, Herndon, VA, USA, (4) US Geological Survey, Wichita, KS, USA, (5) US Geological Survey, Reston, VA, USA, (6) DOI Orphaned Wells Program Office, Denver, CO, USA, (7) US Geological Survey, Troy, NY, USA,

Abstract:

Orphan oil and gas wells are defined as abandoned wells with no financially responsible operator to plug the well and remediate the well site. These wells may pose significant environmental and safety risks through uncontrolled methane emissions. The United States Geological Survey (USGS) is conducting a study that presents the first national-scale analysis of methane emission measurements from 1,445 orphan wells collected across thirteen U.S. states between 2020 and 2024 by the Department of the Interior’s Orphaned Well Program Office. These measurements, the largest such dataset compiled to date, in both size and scope, reveals that 76% of orphan wells in the study have methane emissions rates that are below detection thresholds, which is variable for each gas detection device, and therefore cannot be quantified using available methane measurement field equipment. The mean methane emission rate for all wells in the study is 122.6 grams per hours (g/h) and 517.2 g/h for only the wells with measurable methane emission rates. Emission measurements were highly skewed, with 3% of wells accounting for 90% of total emissions. Mean emission rates varied widely by basin, from <1 g/h in the Cherokee Basin to ~700 g/h in the Piceance Basin, with the Denver-Julesburg Basin exhibiting the broadest range of emissions (0.01 to ~76,000 g/h). Emissions from each well were compared to many variables, including target formation, target age, location, total depth, drill date, date of well abandonment, production tests, cumulative production, well type, product type, well orientation, subsurface geologic feature (basins, uplifts, etc), structural basin type, and change of operator, etc. Methane emissions showed weak correlations with most individual variables, but gas-oil ratio (GOR) and well depth exhibit statistically significant relationships with both the proportion of leaky wells as well as the leak rates. This variability highlights the influence of well product type and higher temperature and pressure in deeper wells on well integrity and resulting methane emissions. These findings provide statistically robust evaluation of emissions rates and add valuable context for assessing emissions rates reported elsewhere. These findings also support the development of targeted strategies for prioritizing well plugging focused on high GOR and deep total depth wells to maximize emissions mitigation.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9323

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