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Examples of Key Workshop Themes

Workshop planning committee chair Mary Feeley, formerly of ExxonMobil, commended the workshop speakers and participants for interesting discussions that revealed the breadth and complexity of the issues associated with orphaned wells. She summarized examples of key themes from the workshop, including lessons learned, challenges, and opportunities mentioned by the speakers and participants over the course of the 2-day event. The highlighted themes signify discussions from the workshop, but are not statements of consensus.

Feeley described the impressive set of state experiences that was shared during the workshop. She reiterated that states have been doing this work for years, and understanding and sharing their plugging and abandonment best practices is critical to move the field forward—a possible next step is to consider how best to gather and disseminate this expertise.

Feeley highlighted similarities in guidance and practices across states as well as the ability of some states to adopt practices from other states. However, she said that states also have unique environments and conditions, and understanding complex geology (e.g., the subsurface, the movement of contamination away from the wellbore, and groundwater issues) is important for achieving successful plugging and remediation. Uncertainties in these environmental conditions are also complex; therefore, several workshop speakers observed that orphaned well programs benefit from the flexibility to plan and design for unique situations. They also benefit from having the ability and flexibility to address unforeseen issues that arise during the plugging and remediation processes.

Several speakers mentioned the importance of experienced and qualified professionals. Feeley emphasized speakers’ assertion that the field could benefit from the inclusion and upskilling of more plugging professionals, regulators, inspectors, petroleum engineers, and hydrogeologists. Furthermore, it was mentioned in the workshop

that well-trained operators are preferred for reentering wells, because re-pressurization, in particular, is challenging and risky. Many workshop participants noted that better assessing the qualifications of plugging and abandonment contractors could be beneficial for long-term plugging success, especially considering the number of wells that have had to be re-plugged.

Feeley next considered the workshop’s focus on states’ approaches to well-plugging prioritization, reflecting on their high-priority concerns about proximity to people, methane, surface water, and groundwater. In terms of the plugs themselves, several workshop speakers commented on the issues surrounding cement and noted that new and evolving technologies for barriers continue to emerge. As uncertainty about the lifetime of cement plugs remains, they encouraged continued research into alternate materials and approaches. Tagging of plugs was considered an important part of the plugging process by many speakers, and new guidance, regulations, and technologies (e.g., drones) for locating and monitoring wells continue to materialize.

Furthermore, reclamation, which is a top priority for tribal lands and parks, could be more successful if included in the plugging plan from the beginning, Feeley continued. Early planning for restoration of the soil and the surrounding environment to stop contamination issues from continuing after operations are complete is important. A few workshop speakers noted that reclamation might double plugging costs (i.e., the incremental costs of surface work could double the downhole cost, thus tripling the total); remediation is also costly but is an important step.

Feeley presented key uncertainties that remain, such as the best approach toward long-term monitoring to understand issues related to well integrity and groundwater contamination. Instead of monitoring every well, some participants suggested that targeted monitoring to better understand the issues of different aspects of plugging and abandonment could be valuable. Other uncertainties relate to the effects of micro-seismicity and considerations of regulations for well re-use and carbon credits. As the workshop drew to a close, she invited speakers and participants to continue to share their thoughts and provide feedback to move this work forward both in the upcoming National Academies of Sciences, Engineering, and Medicine consensus study on orphaned and abandoned wells and in the field more broadly.