By Dan Dall'Acqua
Casing deformations in multistage hydraulically fractured horizontal oil and gas wells have been the subject of considerable work in recent years. Such deformations generally manifest as downhole wellbore access issues that can lead to lost efficiencies during well construction, well completion, and subsequent re-entries, and in some cases, reduced total recovery. They can present a challenge for drilling and completions teams, and are a great example of the importance of cross-disciplinary collaboration.
The SPE Well Integrity Technical Section is home to the SPE WITS Casing Deformation Work Group, which is a volunteer group of interested SPE members formed in 2021 that has been actively pursuing its stated mission of reducing the impact and increasing understanding of casing deformations in multi-fractured horizontal wells. The Work Group initially undertook three initiatives: definition of common language (nomenclature) for describing key facets of this topic, compilation of casing deformation literature, and consideration of the best mechanisms for gathering and sharing data on casing deformation experiences.
There are a wide range of root causes that have been identified through industry experience with casing deformation in multi-fractured horizontal wells. These can range from issues related to casing and tools (“Type I” deformations), cement quality (“Type II”), localized tectonics and rock properties (“Type III”), and operational factors (“Type IV”). Interestingly, in certain basins such as the Western Canada Sedimentary Basin, Neuquén (Argentina), and Sichuan and Qaidam (China), reported deformations in the published literature suggest Type III deformations are the most prevalent. Recently-released paper SPE 217822 contains a comprehensive review of what has been published in this domain.
It has been a busy few months for SPE activity related to casing deformation! Recent events have included a future-facing SPE Forum on the topic (Galveston, December 2023), presentation of the literature compendium paper at HFTC and for the Hydraulic Fracturing Technical Section February webinar, and a lively special session immediately following HFTC (The Woodlands, February 2024) that included operator case study presentations and open conversation with those in attendance. Watch for more activities on the Work Group home page, and contact the co-chairs if you are interested in getting involved!