Vale field: Deployment of subsea assets

Vale is an oil and gas field located in the central part of the North Sea, at a water depth of 115 metres. The field was discovered in 1991, and the plan for development and operation (PDO) was approved in 2001. Vale is developed with a subsea template and one horizontal production well with a single sidetrack, tied back to the Heimdal facility. Production started in 2002.

The current project concerns a well that is no longer in production, and the subsea assets are part of the preparations for plug and abandonment.

Semar delivered fast‑track engineering and planning for the loading, transport, and installation of the subsea equipment. The project was executed in close collaboration with Well Expertise for Sval Energi, using the offshore construction vessel North Sea Giant.

As part of the delivery, Semar provided vessel specifications to support the vessel selection process, ensuring the chosen vessel met all operational requirements and maximized the weather window for a North Sea winter campaign. Our team planned the marine operations, prepared custom sea‑fastening drawings for launch and recovery as a safety back‑up, and optimized the deck layout in close collaboration with contractors and the vessel crew. The scope also included installation analyses, procurement coordination with the mobilization base, and provision of offshore personnel during execution.

Semar’s project engineers developed detailed procedures and took an active role in the mobilization, ensuring all preparations and sea fastening were completed safely and correctly. After the offshore scope was completed, Semar supported vessel demobilization and ensured an efficient and orderly close‑out.

The project involved third‑party verification by DNV, who reviewed and approved key engineering deliverables. All required vessel modifications were designed and implemented in close dialogue with the vessel owner, in accordance with DNV and NORSOK standards.

Semar facilitated kick-off/HAZID and HAZOP workshops with Sval Energi and key suppliers, ensuring thorough and relevant risk assessments and proper integration of all equipment into the operational scope. These actions were implemented throughout the project and contributed to a safe and successful offshore campaign.

The scope also included specification work and engineering support for the ROV subsea operations.

Scope of work summary

• Vessel visit/familiarization prior to start-up
• Engineering and planning of operations
• Subsea installation
• Offshore lifting modelling and analyses
• Project engineering during offshore campaign
• Seafastening
• HAZID/HAZOP
• Procurement
• Supplier coordination
• Project management

Key figures

Client: Sval Energi / Well Expertise

Project duration: 2025

Project characteristics: Decommissioning, plug and abandonment

Mobilization Base: Sløvåg

“I can’t find anything to complain about”

Crane Operator NSG during presentation of deck layout