Misconceptions Regarding Chemical Role of Completion/Packer Fluids…

Misconceptions Regarding the Chemical Role of Completion/Packer Fluids in Annular Environmentally Assisted Cracking of Martensitic Stainless Steel Tubing

Suggested Citation

McKennis, J.S., Sook-Bae, N., Termine, E.J., Shimamamoto, K., and Kimura, M. 2010. Misconceptions Regarding the Chemical Role of Completion/Packer Fluids in Annular Environmentally Assisted Cracking of Martensitic Stainless Steel Tubing. SPE J. 15 (4): 1098-1103. SPE-121433-PA. doi: 10.2118/121433-PA.

SUMMARY

The increased use of corrosion resistant alloys (CRAs) in deep high-pressure/high-temperature (HP/HT) wells has led to production-tubing cracking failures throughout the industry. Many of these failures have occurred from the outside (annulus side) and have been attributed to environmentally assisted cracking (EAC) and, hence, are best described as annular EAC (AEAC). Examination of these failures points to a serious incompatibility of the production tubing metallurgy with the packer fluid under stress.

In 2003, combining expertise in fluid chemistry and metallurgy, the authors formed a research alliance to address the AEAC problem by examining the compatibility of a wide spectrum of completion fluids with various martensitic stainless steel (MSS) metallurgies. This unique research collaboration, involving extensive stress-cracking testing performed with different metallurgies and different fluids under simulated well conditions, has resulted in an extensive database (more than 4,000 test entries for 27 fluids and six MSS metallurgies) and a new body of knowledge regarding the causes behind AEAC failures.

Conventional wisdom holds that chloride ion and oxygen play major causative roles. The authors’ findings, however, identify other contaminants in completion/packer fluids that play the dominant role in the chemical mechanism of the crack failures. Such contaminants include sulfur-containing species, oxidants other than oxygen, and select basic ionic species. This paper addresses the effect of the new information and identifies serious misconceptions regarding the role of completion /packer fluids in the tubular failures.

The authors’ comprehensive study has advanced the industry’s knowledge of the causes of AEAC by detailing the previously unrecognized importance of various contaminants present in the fluids. As a consequence, the need for quality assurance and best-practice fluid management throughout the life cycle of the fluids is now recognized. Misconceptions with respect to the chemical mechanisms and causative factors of AEAC failures are discussed. Such information should expand the industry’s AEAC knowledge base and minimize the risk of tubular failure.

© 2010. Society of Petroleum Engineers
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Reprint available from SPE

Written by

Dr. Enrico J. Termine is a senior executive and scientist with thirty years of experience in business leadership, research & development, product engineering, marketing, and manufacturing. He has consulted for a variety of industrial and legal clients on engagements involving valuations, due diligence assignments, market research reports, strategy development reports, science and technology assessments, and root cause investigations. Dr. Termine is a bromine chemistry expert. He specializes in oilfield applications, flame retardant plastics, industrial and recreational water treatment and disinfection, specialty and fine chemicals, polymer additives, plastics, and organic synthesis for life science molecules and advanced materials. Dr. Termine earned both his Bachelor of Science in Chemistry and his Ph.D. in Organic Chemistry from the University of Miami. He has collaborated on more than 38 patents and publications. His technical contributions are useful in consumer electronics; for petroleum and petrochemical processing; in transportation and industrial products; in healthcare; for industrial and household disinfection; and in building and construction materials.

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