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Quantification of Methane Emissions from Marginal (Small Producing) Oil and Gas Wells
Project Number
Last Reviewed Dated

The objective of this research is on measurement of methane emissions from marginal well sites at various basins across the United States. The goal is to collect and evaluate representative, defensible and repeatable data from marginal well sites and draw quantifiable conclusions on the extent of emissions from marginal wells across oil and gas producing regions of the United States., and to compare these results to published data available on the emissions from non-marginal wells.


GSI Environmental (GSI), Austin, TX 78759
Gas Technology Institute (GTI), Des Plaines, IL 60018
Colorado State University (CSU), Fort Collins, CO 80523
Research Partnership to Secure Energy for America (RPSEA), Houston, TX 77098


The Environmental Protection Agency (EPA) issued a final rule on June 3, 2016, to amend the New Source Performance Standards (NSPS, 40 Code of Federal Regulations Part 60, Subpart OOOOa) to reduce methane emissions from new and modified oil and natural gas facilities. These new requirements include oil wells which produce <15 bbl per day or gas wells that produce <90 MCF per day, which were not previously addressed. EPA’s decision to no longer exempt these “marginal” wells from the Leak Detection and Repair (LDAR) requirements was developed based on limited data.


EPA’s NSPS via Rule OOOOa assumes that low-producing marginal well facilities have the same type and number of equipment and episodic emissions as higher producing sites and, therefore, contribute similarly to national emissions. The costs of compliance may impact all producers but will, in particular, affect small oil and gas operators of the almost 760,000 marginal wells located throughout the United States, with an associated economic impact. This study will provide a robust, “apples-to-apples” assessment of methane emissions from marginal vs. non-marginal well sites based on the quantity and condition of equipment and components within these populations and related operational information. To accomplish this, detailed operating conditions, such as frequency, equipment type, and component counts will be analyzed in conjunction with oil and gas production data for each site, production region, and as a whole.

Accomplishments (most recent listed first)
  • On October 28, 2019, GSI initiated the first of three planned campaigns to measure and assess methane emissions from marginal oil and gas wells. In the first three weeks of this planned five-week campaign centered on operations in the Appalachian Basin, the GSI team surveyed 115 sites and made equipment counts at each of these sites. At 50 of these sites, GSI collected a total of 82 discrete emissions measurements.
  • GSI developed and submitted for review a Master Workplan outlining the technologies and protocols to be used during field campaigns. Regional Workplans specific to the three planned regional field campaigns will be developed with the first region field campaign — for the Appalachian and Illinois Basins — submitted on October 1, 2019.
  • On August 5 and 6, 2019, GSI held four meetings (two per day) with industry, state and federal agencies, and other stakeholders to present the findings of the recently completed Data Source Status Assessment (DSSA). The DSSA utilized published sources and information derived from operator surveys to identify gaps in the current understanding of emissions from marginal vs. non-marginal wells.
  • GSI held calls with the Technical Advisory Steering Committee (TASC) on April 11, 2019, and a second round of calls on April 15, 2019. The purpose of these calls and involvement of the TASC is to guide and advise on key aspects of the project work scope. The TASC will be tiered with a full committee that includes representation from industry, regulators, non-government organizations, and academia, and a sub-committee comprised of industry representatives only.
Current Status

The project team has begun the first regional methane emissions monitoring campaign. This five-week campaign includes monitoring of marginal wells in Appalachia (Pennsylvania, Ohio, and West Virginia), Indiana, and Kansas.

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DOE Contribution


Performer Contribution


Contact Information

NETL – Robert Vagnetti ( or 304-285-1334)
GSI Environmental – Ann Smith/Ric Bowers ( or 512-346-4474)