Technology Focus: Cementing and Zonal Isolation (May 2023)

Abstract

In 2022, the topics of the cementing and zonal isolation papers published were generally similar to those presented in previous years. A noticeable departure from previous years, however, was that many of the authors emphasized that their work would result in a reduction of greenhouse-gas emissions. The approaches taken to reduce emissions can be broadly split into three categories: improving operational efficiency, increasing the reliability of zonal isolation (primary cementing, annulus leak repair, and plug sealing), and reducing the CO2 footprint of sealing materials. Work to improve operational efficiency and increase the reliability of zonal isolation has been ongoing since the start of well construction as general good practice to improve safety and hydrocarbon recovery and reduce costs. The efficiency and reliability improvements, however, have not regularly been promoted as reducing the environmental impact, except for cases of leak repair. Reduction of the CO2 footprint of sealing materials is a growing source of research and development activity and subsequent publication. During the past year, 13% of the cementing and zonal isolation papers published covered work on the development of geopolymer systems. Although work to develop geopolymer systems for zonal isolation has been ongoing for more than 15 years, no case histories have been published to date. The long development time is not surprising because any new system will have to be at least as reliable as the current Portland-cement-based systems; otherwise, the overall environmental impact may be worse, with more repairs or less-efficient processes offsetting the reduced CO2 footprint of the sealant. Geopolymers are not the only option to replace Portland-cement-based systems for primary cementing, and the evaluation of alternate sealant systems is certainly not new (see paper SPE-508-G from 1956). Is it time to revisit previous work in light of new environmental constraints? Recommended additional reading at OnePetro: www.onepetro.org. IPTC 22019 Enhancing Slurry Pumping Efficiency, Improving Cement Coverage, and Ensuring Zonal Isolation With Temperature-Triggered Antisettling Technology by Xiangyu Liu, ChampionX, et al. SPE 210639 Thermodynamic Modeling on Wellbore Cement Integrity During Underground Hydrogen Storage in Depleted Gas Reservoirs by Lingping Zeng, Curtin University, et al. OTC 31562 Cementing the First Australian Offshore Carbon Capture and Storage Appraisal Well by Ariel Lyons, SLB, et al.