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oa Assessing the Mechanical Impact of CO2 Injection on Faults and Seals
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 2nd EAGE International Conference on Fault and Top Seals - From Pore to Basin Scale 2009, Sep 2009, cp-136-00056
- ISBN: 978-90-73781-69-6
Abstract
Two options for geological storage of CO2 are currently considered: storage in depleted hydrocarbon fields, which have a hydrocarbon proven seal, and storage in deep (>800m) saline aquifers, which lack such a seal. Pore pressure changes resulting from fluid extraction and subsequent CO2 injection into the reservoir induce stress changes that may mechanically damage seals, or trigger existing faults, creating the leakage pathways for CO2 escape from the containment. It is therefore required to predict the impact of CO2 injection and long-term storage on seals and faults. This is commonly done as a part of feasibility study carried out to assess the storage capacity and containment characteristics of the selected candidate site. In this paper we examine current practices for geomechanical evaluation of the mechanical impact resulting from pressure build-up on seals and faults. Discussion is supported by the results from recently accomplished studies of currently active and future potential storage sites, e.g. the Sleipner site located offshore in Norway (ongoing CO2 injection since 1996)and the De Lier depleted field located onshore in the Netherlands.