Title
Assessing the short-term and long-term integrity of top seals in feasibility studies of geological CO2 storage
Author
Orlic, B.
ter Heege, J.H.
Wassing, B.
Contributor
Orlic, B. (editor)
ter Heege, J.H. (editor)
Publication year
2011
Abstract
The geomechanical effects of past hydrocarbon production and subsequent CO2 injection in depleted gas reservoirs were evaluated as a part of several recently accomplished feasibility studies of CO2 storage in the Netherlands. The objectives of geomechanical studies were to assess the mechanical integrity of a reservoir-seal system, i.e. the containment, and the induced ground movement, aseismic and seismic. Geomechanical numerical models of the candidate sites make it possible to investigate and quantify production- and injection-induced stress changes in and around the reservoir. Numerical models reveal, as illustrated by a case study presented, that the side seal and the boundary faults at the edges of reservoir compartments represent weak spots where production-induced mechanical damage and fault re-activation will first occur. Possible permeability enhancement resulting from local seal damage and fault slip can provide the initial pathways for CO2 penetration into the seals enhancing fluid-rock chemical interactions. The long-term effects of chemical reactions on the strength of a sample of representative anhydrite caprock indicate that the strength is reduced by one quarter after 50,000 years of exposure to CO2.
Subject
Earth / Environmental
SGE - Sustainable Geo Energy PG - Petroleum Geosciences
ELSS - Earth, Life and Social Sciences
Geological Survey Netherlands
Geosciences
Energy / Geological Survey Netherlands
CO2 storage
Seal integrity
Fault integrity
Fault reactivation
Reservoir geomechanics
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http://resolver.tudelft.nl/uuid:d0aa187d-f0ae-4c8a-9586-e837a006f0b7
TNO identifier
503690
Publisher
CATO-2
Source
CATO-2 Deliverable WP3.03-D10 : Reservoir-caprock-overburden deformation and effects on caprock integrity : Final Report, 2011, 17-33
Article number
ARMA 11-375
Bibliographical note
Paper presented at the 45th U.S. Rock Mechanics / Geomechanics Symposium
Document type
conference paper