Lessons learned from 14 years of CCS operations: Sleipner, In Salah and Snøhvit

TLDR

Operational experience from Sleipner, In Salah, and Snøhvit—injecting CO₂ for 14, 6, and 2 years in reservoirs with permeability ranging from milliDarcy to Darcy—illustrates the challenges of CO₂ storage, while scientific debates focus on pore‑space utilisation and pressure‑dissipation limits. The study argues that detailed site characterisation and monitoring are required to demonstrate practical CO₂ storage capacity on a case‑by‑case basis. Geophysical monitoring—seismic, gravity, and satellite data—has revealed unpredicted geological factors at each site. The three sites have disposed 16 Mt of CO₂ by 2010, with plume development strongly governed by geological factors, showing that monitoring methods are essential for reservoir characterisation and may enable general conclusions on storage capacity, injectivity, and efficiency.

Abstract

In the paper we share our operational experience gained from three sites: Sleipner (14 years of injection), In Salah (6 years) and Snøhvit (2 years). Together, these three sites have disposed 16 Mt of CO2 by 2010. In highly variable reservoirs, with permeability ranging from a few milliDarcy to more than one Darcy, single wells have injected several hundred Kt of CO2 per year. In the reservoirs, the actual CO2 plume development has been strongly controlled by geological factors that we learned about during injection. Geophysical monitoring methods (especially seismic, gravity, and satellite data) have, at each site, revealed some of these unpredicted geological factors. Thus monitoring methods are as valuable for reservoir characterisation as they are for monitoring fluid saturation and pressure changes. Current scientific debates that address CO2 storage capacity mainly focus on the utilization of the pore space (efficiency) and the rate of pressure dissipation in response to injection (pressure limits). We add to this that detailed CO2 site characterisation and monitoring is needed to prove significant practical CO2 storage capacity–on a case by case basis. As this specific site experience and knowledge develops more general conclusions on storage capacity, injectivity and efficiency may be possible.