Overview
AISUS was approached by a client to provide cleaning, remote visual inspection, and corrosion mapping of various conductors in preparation for heavy lift vessel platform removal. The conductor being a critical component of any fixed platform. Between the wellhead and the seabed these casings are subject to thermal and pressure loads, as well as wave corrosion.
The Project
The conductors secured by guide frames are typically snug-fitting and do not allow external inspections to be carried out. As a result, external non-destructive testing cannot be performed to assess the conductor’s external condition at these points, requiring the development of internal solutions.
Requirements
A remote visual inspection was required for the length of the conductors to identify debris removal and cleaning of fluids to ensure visibility. Special attention was paid to the internal area where the guide support frame was positioned. Circumferential welds and internal conditions were required to be determined. Corrosion mapping would follow, with a resolution of us to 2x2mm grids.
Solution
The preliminary remote visual inspection will determine the condition of the conductor and execute a targeted approach to any specific areas. Deploying the visual inspection also allowed for retrieval tools to remove any blockages to make way for the corrosion mapping inspection.
Challenges
The scope was carried out late in the day and may have caused additional delay to heavy lifting.
The number of foreign objects and debris was essentially unknown. Large debris weighing up to 150kg to be removed.
The debris prevented the equipment from being deployed to the required depth of the conductors.
Special attention was to be paid to areas behind the guide frame where damage could not be determined externally.
Key Benefits
AISUS delivers these projects as a complete package, minimising the complexity of coordinating multiple third parties.
Single sourcing of personnel and equipment resulted in the reduction of costs, including a number of flights and shipping costs.
The streamlined approach not only prolonged the asset’s lifespan but also minimised further damages due to build up of blockages
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