No abstract

and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

No abstract

Inactive oil and gas wells present an environmental hazard if not properly plugged. Upon drilling a well, operators are required to post a bond, which ensures that the operator has an incentive to plug and abandon (P&A) at the end of the well's life, and that, if the state is left with the liability of managing "orphaned" wells, it can cover the cost of P&A. Using data from 13 state agencies on their orphaned well plugging expenditures, we provide new estimates of P&A costs in the United States and compare them to bond amounts. Current state bonding requirements are insufficient to cover the average P&A cost of orphan wells in 11 of these 13 states. These should be reviewed and revised where necessary. We also examine the factors influencing P&A costs using detailed data on orphaned wells in Kansas. Given the variability of P&A costs, bonds would be more effective if they varied by factors that are meaningful in explaining P&A costs, such as well depth, location, and proximity to groundwater. State regulators can use the statistical approach developed in this paper to improve bonding requirements and to better predict the P&A costs of their orphaned wells.

No abstract