A new study concludes the United States has underestimated the amount of yearly methane emissions from abandoned oil and gas wells. The research comes from McGill University in Montreal, Canada, and was published in the journal Environmental Science & Technology. The study shows the US underestimated annual methane emissions from orphan wells by 20% while Canada underestimated orphan well emissions by as much as 150%.
Orphan wells are a growing problem across the country with Pennsylvania having a large number of them. This study estimated the number of non-producing oil and gas wells in the US at more than 4 million and contends about 12% of them are not accounted for in state records. The Biden administration has recognized the problem, and has proposed spending $16 billion to plug orphan wells as part of a $2 trillion infrastructure plan.
The McGill researchers used a combination of state and provincial databases, national repositories and research articles to tally the numbers. Because of the uncertainty of how many abandoned wells exist, the amount of methane they emit can’t be accurately calculated.
Pennsylvania is among the states with the highest number of abandoned wells, along with West Virginia, Oklahoma, Kansas, and Texas. Altogether, those states account for 65% of the country’s orphan wells. The study says those same states are the highest emitters of heat-trapping methane with Pennsylvania topping the list followed by Texas, West Virginia, and Kansas and contends that Environmental Protection Agency estimates of those emissions are too low. The authors estimate methane emissions from orphan oil and gas wells make up 10% of the total methane emissions from the US oil and gas sector.
The Pennsylvania Department of Environmental Protection has an Abandoned and Orphan Well program and estimates hundreds of thousands of oil and gas wells have been drilled in Pennsylvania since 1859. DEP said staff research the status of legacy oil and gas wells and are developing approaches for estimating greenhouse gas emissions associated with the historical well population. The current orphan, abandoned, and DEP plugged well map as of early February 2021 shows 11,693 sites across Pennsylvania with 6185 listed as orphan, 3067 as plugged and 2440 as abandoned.
The US EPA estimates there are between 2.3 million and 3 million abandoned gas wells across the U.S. The state DEP estimates the cost of plugging a single well can range from tens of thousands to more than $100,000. If the Biden plan received Congressional approval, it could provide significant help in addressing the issue, but that is not assured.