An agile clamp for emergency pipe repairs
A project presented by Lhavy Etaba-Obani and Dany Mingas
The daring design and installation of a temporary clamp on a flowline termination (FLET) in the Moho-Bilongo field in the Congo saved several months in the repair of a leak in a water-injection pipeline. This pragmatic, rapid and innovative solution prevented the loss of 600,000 barrels.
A change of perspective ahead of... a vanishing point
The leak in the pipe was detected on January 14, 2020. Injection operations were halted on January 25. The location of the leak inside the FLET made it impossible to plug permanently using the traditional method of a remotely-operated submarine vehicle (ROV). The repair required a total replacement of the FLET, a major operation involving more than six months of work and a halt in production, an impact estimated at 195,000 barrels per month.
Using digital modeling of the FLET and ROV, TotalEnergies’ teams showed that certain limited maneuvers could give the ROV direct access to the defective part. This possibility gave rise to a much more practical alternative solution that took very little time to implement: the simplified design and installation of a temporary clamp on the leak to stop it on a provisional basis.
An adapted clamp, a simplified technology
The design of this pipe clamp is customized to structural constraints of the FLET, such as the internal pressure of the flowpath, and those involved in adapting to the ROV: it needed to be lightweight, to prevent any additional constraint on the pipe, which had been made fragile by the leak, as well as reliable and easy to handle for the transportation and installation. Its innovative design is based on the combination of three simple things:
- A simple mechanical lock using a bolt tightened by the ROV.
- A large elastomer joint that does not require an intricate installation on the leak.
- A seal obtained by compressing the elastomer during the mechanical tightening.
This sturdy clamp was designed and manufactured in strict compliance with the SP8 standards. It was tested under real conditions during the installation and proved its reliability over several months before the definitive repair work, at a depth of 727 meters and at normal operational pressure.
A rapid, 100% digital, agile and cross-functional design
Even as the whole world was under lockdown due to Covid-19, the project continued on, managed remotely using digital technology from the design stage to the placement of the clamp, at seven different sites. The seal and operational tests carried out in Norway were monitored and validated in real time via video transmission.
- This 100% digital and remote approach enabled significant gains in terms of organizational and operational effectiveness.
- From the study phase to installation, the project was conducted in agile mode within a very short timeframe: less than 90 days, compared to 6 to 12 months for a conventional repair. The clamp was installed in 48 hours, the leak was sealed and production started up again in May 2020 using only the internal resources of the affiliate Total E&P Congo without any additional intervention.
- The simplicity of this system’s design keeps its manufacture and installation costs down.
- The rapid installation of a temporary clamp made it possible to prevent additional damage to the integrity of the repaired equipment.
This easy-to-use temporary repair system could be expanded for use in emergency repairs in other types of pipes as well as in applications on land, for example in distillation.
The project team
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