Wellbore Integrity Challenges in the Era of Energy Transition

Abstract CO2 sequestration in geological formations such as saline aquifers and depleted oil and gas reservoirs, increasing geothermal energy's share in the energy mix, and storing hydrogen produced from excess green electricity in geological formations are promising strategies to achieve the net-zero target by 2050. Wellbore integrity is a critical component of any subsurface operations. Historically, a significant portion of petroleum industry literature has focused on ensuring well integrity for safe and efficient production as well as abandonment. However, the energy transition introduces novel challenges to well integrity that remain largely unexplored and unaddressed. Wellbore integrity from a traditional standpoint will be revisited and compared with the emerging requirements driven by energy transition applications. Key challenges are identified, and actionable recommendations are proposed based on these evaluations. Our findings from laboratory experiments conducted over recent years on wellbore integrity for geothermal projects, geological CO2 storage, and hydrogen storage are summarized. The comparisons provide insights into how wellbores in the new era must evolve to meet the technical demands of the energy transition while maintaining safety, efficiency, and environmental compliance. This study identifies critical knowledge gaps in wellbore integrity and underscores areas that require further investigation. Case studies from geothermal projects in Germany are presented, showcasing practical applications and results. The permeability measurements of various wellbore components, conducted in our laboratory over the past three years, are discussed in the context of CO2 storage projects. Furthermore, with hydrogen storage in salt caverns anticipated to play a pivotal role in the energy transition, our experimental findings on wellbore integrity in such settings are briefly summarized. These results collectively emphasize the need for continued research and detailed investigations to resolve remaining challenges and support the safe, long-term use of subsurface formations for energy transition applications. The work consolidates common wellbore integrity issues across various energy transition applications, offering a unified perspective based on literature review and our laboratory's extensive experience. It highlights critical challenges and proposes future research directions to address the evolving needs of subsurface operations in the energy transition era.