08 September 2026

Valaris 123 drilling rig departs; the Seafox 4 takes over

Now that work on the wells has been completed, the Valaris 123 drilling rig, which is moored alongside the Porthos P18-A platform, will soon be replaced by the Seafox 4. The Seafox 4 is an accommodation platform and offers more space for the equipment that currently still needs to be stored on the P18-A platform.

The Valaris 123 was used to convert four of the six former P18 gas production wells into CO₂ injection wells. The other two have been permanently sealed. The Valaris 123 had been moored alongside the Porthos P18-A platform since March 2025 and was clearly visible from the coast. With the successful conversion of the wells, the work of this drilling platform has come to an end. The Valaris 123 will be disconnected in the next few days and towed away to its next assignment. In the next phase of the conversion operation, the Seafox 4 will serve as an accommodation platform. This ‘jack-up rig’ can be raised to the required height to connect properly with the Porthos platform.

Thanks to its wider and longer design and large crane, the Seafox 4 offers greater storage capacity for the materials and equipment required to carry out the remaining conversion work. Following the arrival of the Seafox 4, further work on P18-A will be coordinated from this platform. The Seafox 4 also provides accommodation for the staff who live and work on board during their offshore stay.

The Seafox 4 is scheduled to depart at the end of this week from an offshore converter platform in the German North Sea, heading for the Porthos P18-A platform, approximately 20 kilometres off the coast of the Maasvlakte near Rotterdam. The Seafox 4 is expected to come alongside the P18-A platform in the course of next week, after which the Valaris 123 will depart.

In the video below, Angus Fraser, Rig Manager at Valaris, talks from aboard the Valaris 123 about his work and experiences on board during the deployment for the Porthos project.