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?
This Month’s Technical Papers
Expandable Geopolymers Improve Zonal Isolation and Plugging
Studies Quantify Cement Sealing Performance Under Downhole Conditions
Study Compares Methods To Measure Static Gel-Strength Development
Recommended Additional Reading
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 Reservoirsby Lingping Zeng, Curtin University, et al.
OTC 31562 Cementing the First Australian Offshore Carbon Capture and Storage Appraisal Wellby Ariel Lyons, SLB, et al.
Simon James, SPE, is an independent consultant for well cementing, product development, and innovation. He has more than 30 years of experience in oilfield research and development, covering cementing, fracturing materials, screenless completions, and drilling fluids. James has developed and commercialized solutions for primary cementing, plugging and abandonment, and repair of sustained casing pressure. He also contributes to the development of industry standards. James has coauthored more than 25 technical papers and is inventor or coinventor on 38 granted US patents. He holds a BA degree in natural sciences and a PhD degree in physics, both from the University of Cambridge. James is a member of the JPT Editorial Review Board and can be reached at simon@cs8-consulting.com.
