Sleipner CCS: The Gold Standard for 4D Monitoring

Decision context

Sleipner stores CO₂ in the Utsira saline aquifer beneath the Norwegian North Sea. The central monitoring question is not simply whether a time-lapse signal can be detected, but whether repeated evidence can show how the plume evolves and whether it remains contained within the intended storage interval.

Monitoring approach

Repeated marine seismic surveys provide a consistent view of plume development through time. The workflow uses time-lapse amplitude changes to distinguish the injected CO₂ from the surrounding brine-filled formation and to follow its movement between internal layers.

Evidence

• Plume distribution: Time-lapse images reveal the lateral and vertical development of the CO₂ plume.
• Layer interpretation: Amplitude analysis supports interpretation of the distribution and thickness of individual CO₂-bearing layers.
• Continuity: The long survey record makes Sleipner a reference case for evaluating how storage evidence accumulates over time.

Operational outcome

The monitoring record supports assurance that the injected CO₂ remains within the storage complex and gives regulators and project teams a repeatable basis for reviewing plume behaviour.

Transferable lesson

A mature storage-monitoring program links survey repeatability to a specific containment question. The value comes from the continuity of the evidence record, not from any single seismic image.