SLB has been selected as strategic reservoir partner for the Havstjerne carbon storage development in the Norwegian North Sea, taking an integrated engineering role across the storage reservoir, injection wells and subsea infrastructure ahead of a final investment decision.
The appointment covers concept development and front-end engineering and design rather than construction of an already sanctioned storage project. Harbour Energy, which operates Havstjerne with Stella Maris CCS as partner, is using the work to develop the technical, cost and schedule basis needed before committing the scheme to full execution.
SLB will provide early engineering, subsurface maturation and well work, while its OneSubsea joint venture will carry out concept and FEED activity for the offshore injection system. The proposed subsea scope includes a template manifold, all-electric trees, a control system, umbilical and distribution equipment.
Bringing those disciplines together early is intended to reduce the number of assumptions passed from one engineering package to another. Reservoir pressure behaviour and expected injection performance influence the number, position and design of wells, while the wells determine requirements for subsea controls, flow assurance, monitoring and the equipment needed to connect the storage formation with the transport system.
An appraisal well drilled in 2025 provided the project with direct information on the planned storage reservoir. Harbour Energy said the well encountered reservoir quality suitable for carbon dioxide storage and collected data intended to support further technical studies, including information on injectivity and the behaviour of the formation.
That evidence moves Havstjerne beyond reliance on regional geological modelling, although an appraisal result does not remove the development risks associated with commercial injection. A storage project must demonstrate that the formation can accept the required volumes and pressures over time while maintaining containment, and those assumptions have to remain credible across changing operating conditions.
The project is owned 60% by Harbour Energy and 40% by Stella Maris CCS, which is part of Yinson Production. It is located in the Norwegian North Sea south-west of Stavanger and is being developed as a potential cross-border storage destination for captured industrial carbon dioxide.
Havstjerne was also selected for support from the EU Innovation Fund through the STARFISH project, with up to €225 million awarded in 2025. The funding strengthens the development case but does not amount to final project sanction, leaving engineering maturity, customer commitments and commercial structure among the issues that still have to be resolved.
The current concept uses low-pressure floating storage and injection rather than depending solely on a fixed pipeline from one industrial cluster. Captured carbon dioxide could therefore be transported by ship from emitters or collection hubs before transfer into the offshore injection system.
Shipping can widen the addressable customer base because many European cement, chemical, refining and other process plants are geographically dispersed. Building dedicated pipelines to every emitter would require large early capital commitments, while marine transport allows collection routes to develop around several industrial locations provided terminals, vessels, storage tanks and offshore transfer systems can operate to compatible specifications.
The additional flexibility brings its own constraints. Carbon dioxide has to be conditioned for transport, maintained within defined pressure and temperature limits, transferred safely between ship and offshore system and injected at rates that can be accommodated by both the storage formation and the delivery schedule. Interruptions at a capture plant, port or vessel can therefore affect an injection system even when the reservoir itself remains available.
Gavin Rennick, president of SLB’s New Energy and Industrial business, said carbon storage projects are increasingly connecting “the subsurface, wells and offshore infrastructure”. Havstjerne reflects that approach by giving the same engineering group responsibilities that cross several of the interfaces normally divided between reservoir, drilling and subsea packages.
The use of all-electric subsea trees is another element of the proposed architecture. Removing conventional hydraulic functions can simplify parts of the control system and fits a broader offshore trend towards electrically actuated subsea equipment, although the design still has to meet reliability requirements for an installation intended to remain available over a long storage life.
Monitoring will remain part of that operating life rather than ending at first injection. Storage operators have to demonstrate where injected carbon dioxide is moving and whether reservoir pressure remains within the expected envelope, while wells and barriers require continued integrity management. Engineering decisions made before sanction therefore affect both construction cost and the evidence required years after injection begins.
Havstjerne has reached the point where those decisions are being combined into a development design, but it has not yet crossed the investment threshold into construction. SLB’s appointment should produce a more integrated technical basis for that decision. The next meaningful milestone will be whether the reservoir evidence, customer commitments and offshore architecture can be converted into a sanctioned project rather than another storage licence with an increasingly sophisticated set of engineering studies.
