Unblocking, Debris Retrieval And Coating Removal Project in the North Sea

Case study

Project Overview

AISUS recently completed unblocking, debris retrieval and coating removal for a super major in the UK North Sea.

The client had a problem with a blockage in their produced water discharge caisson. The caisson was internally coated with a polyuria lining that had failed in service. The detached lining accumulated at the termination and plugged the caisson. The blockage meant the client had to re-route the produced water down a temporary discharge hose but as a result had to throttle back production.

Debris Retrieval And Coating Removal

Our competent and experienced inspection engineers were mobilised to complete the project. Firstly, the blockage was removed along with the remainder of the coating on the sidewall allowing the client to reinstate the caisson and increase production without the threat of re-blocking the caisson. This was done utilising in-house designed and manufactured hydraulic grabber tool.

High Pressure Cleaning

Followed by that, the team successfully completed a high pressure cleaning to remove the remaining coating which was collected into a debris basket. Any loose coating obstructing progress of the basket was retrieved successfully and the team completed the project in a safe and efficient manner providing high quality report for the client.


AISUS demonstrated flexibility and industry excellence as the AISUS team picked up and completed the scope safely after a previous vendor had been unable to deliver the project. AISUS’ previous experience in similar scopes meant the team had a great understanding of the type of project and were able to use this experience and knowledge to carry out the project.

AISUS team of talented and multidiscipline engineers were able to provide the complete service from designing and fabricating bespoke tooling, completing yard trials and mobilising the equipment in a fast and safe manner, ahead of the given schedule. The client benefited by only having to deal with one vendor and not multiple vendors and multiple mobilisations.


  • Successful unblocking, debris retrieval and coating removal
  • Full service delivered – no need for multiple vendors
  • Professional and proactive engineers
  • Open communication throughout the project

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