Objectives/ScopeWith an increasing number of wells transitioning to their abandonment stages, associated operational efficiency and cost cutting has become a major focus in the industry. An operator had an objective to permanently abandon an offshore well that was suspended in 2016. The key challenge was to provide develop a long term well abandonment solution leaving the completion tubing and gauge cables in the well. All the associated operations had to be completed utilizing a lightweight well intervention vessel. &nbsp;Methods, Procedures, ProcessTraditionally, retrieving the entire 5 ½-in production tubing during plugging and abandonment operations has added operational complexity and costs, and increases the risk of exposure to HSE hazards. Alternatively, a sealant technique placing cement though and around the completion tubing with gauge cables in-situ exists. However, this technique is associated with a heightened risk of leak path development over time. Ongoing experimental work suggested that enhancements to the conventional cement sealant systems would be beneficial to improve long-term sealing, thus an active self-sealing cement system that would seal microannuli or small fissures around the tubing and gauge cables was designed. The set cement sealant characteristics include low Young’s modulus to resist failure from wellbore stresses, and can regenerate the original seal upon contact with any hydrocarbons that may seep through any isolation defects through the life of the abandoned well. To ensure proper cement placement, advanced fluid simulation software and carefully tailored fluid density and rheology profiles were utilized.Results, Observations, ConclusionsDuring the operation, a plug of the self-sealing cement sealant was pumped through the production tubing and squeezed into the perforations to create a permanent barrier across the reservoir section. Next, a mechanical plug was set inside the production tubing to isolate the lower section, and the tubing perforated to provide access to the A-annulus above; subsequently, a balanced plug of self-sealing cement sealant was spotted above. After 30 hours, the plug passed a 500-psi verification pressure test. The operator estimated the operation saved 2 to 3 days of rig time, valued at approximately GBP 400,000 to 600,000. The operator also avoided the risk of leaving the well on long-term suspension with mechanical plugs while waiting for a rig to complete the isolation, and the operation minimized the number of intervention steps required for abandonment, thereby limiting scope growth.Novel/Additive InformationOperators are constantly looking for ways to increase reliability, improve the efficiency and minimize risks, therefore abandonment techniques are evolving. The following paper outlines a novel and robust alternative to conventional well abandonment using advanced cement sealant technology and innovative placement technique.

Abandonment Solution for Wells With Gauge Cables: An Engineered Self-Sealing Cement System

Paper Proceedings: https://asmedigitalcollection.asme.org/OMAE/OMAE2021/volume/85116

OMAE 2021

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