Project Overview

In August 2024, Deep C supported a subsea excavation in the North Sea to enable pipeline scanning.

The objective was to create a precise excavation under and around the pipe. It had to be large enough to accommodate washing clamps and scanning tools.

The work took place in soft clay and silt conditions that severely reduced visibility during jetting. Careful schedule discipline and plume control were essential to avoid delays further down the line.

The Deep C Solution

Deep C deployed a crane-hung Suction Head paired with a 14” Subsea Dredge spread and introduced an integrated jetting system mounted directly on the inlet. This configuration broke up cohesive clay immediately ahead of suction, improving material uptake and reducing re-deposition under the pipe.

To manage visibility, operations were carefully paced to allow plumes to clear between passes in line with prevailing currents. Tool routing and hose management were optimized to reach directly beneath the pipeline despite tight geometry, ensuring a safe and effective excavation process.

Results

The excavation was completed successfully and provided the required clearance for scanning, including safe access beneath the pipeline. By combining the suction head with an integrated jetting system, the team was able to overcome challenging clay conditions and maintain control throughout the operation.

The approach ensured that visibility management was handled effectively, and the excavation was delivered to specification without disruption to the overall schedule.

The client received a scan-ready pipeline section prepared in line with their requirements, demonstrating Deep C’s ability to adapt equipment and methods to complex seabed conditions.