Remediation of Seepage from CO₂ Storage Formations

Publication Overview

The aim of this study was to assess what remediation techniques and approaches are available if seepage of CO₂ is identified from a geological storage formation. The objective of the study was to develop a report that can act as a reference manual for IEA Greenhouse Gas R&D Programme (IEA GHG) members in their discussions with policy makers. The report sets out the remediation plan that can be adopted in the event of any seepage being detected based upon different types of seepage event and their associated remediation methods. This report also estimates the costs of different remediation measures.

Publication Summary

The most important aspect of seepage prevention and remediation strategy is selecting a safe, secure storage site to begin with. Assuming that a secure CO₂ storage site has been selected, the loss of well integrity and blowouts will most likely represent the greatest risk of CO₂ seepage. In both cases there is experience in other industries for remediation.

In terms of cost, if seepage occurs, the work required for remediation can range from being relatively low to at times being greater or equal to, the costs associated with original CO₂ storage site selection, project design and implementation. However to put these costs in perspective, for a typical storage case the costs for site selection monitoring and remediation could range from $0.45 to $0.50 per tonne CO₂. Compared to the total cost of a CCS project ($35 -50/t CO₂) the additional cost for minimising seepage can be considered as low. Whilst, the financial cost of remediation is low its contribution to public safety and public acceptance cannot be understated and regulatory bodies will not allow projects to proceed without remediation.