Title
Reservoir creep and induced seismicity: Inferences from geomechanical modeling of gas depletion in the Groningen field
Author
van Wees, J.D.
Osinga, S.
van Thienen-Visser, K.
Fokker, P.A.
Publication year
2018
Abstract
The Groningen gas field in the Netherlands experienced an immediate reduction in seismic events in the year following a massive cut in production. This reduction is inconsistent with existingmodels of seismicity predictions adopting compaction strains as proxy, since reservoir creep would then result in a more gradual reduction of seismic events after a production stop. We argue that the discontinuity in seismic response relates to a physical discontinuity in stress loading rate on faults upon the arrest of pressure change. The stresses originate from a combination of the direct poroelastic effect through the pressure changes and the delayed effect of ongoing compaction after cessation of reservoir production. Both mechanisms need to be taken into account. To this end, we employed finite-element models in a workflow that couples Kelvin-Chain reservoir creep with a semi-analytical approach for the solution of slip and seismic moment from the predicted stress change. For ratios of final creep and elastic compaction up to 5, the model predicts that the cumulative seismic moment evolution after a production stop is subject to a very moderate increase, 2-10 times less than the values predicted by the alternative approaches using reservoir compaction strain as proxy. This is in agreement with the low seismicity in the central area of the Groningen field immediately after reduction in production. The geomechanical model findings support scope for mitigating induced seismicity through adjusting rates of pressure change by cutting down production. © The Author(s) 2017. Published by Oxford University Press on behalf of The Royal Astronomical Society.
Subject
Geological Survey Netherlands
Geosciences
2015 Energy
Geomechanics
Induced seismicity
To reference this document use:
http://resolver.tudelft.nl/uuid:b6cec5d3-0934-434b-9a0b-69ba0a779a81
DOI
https://doi.org/10.1093/gji/ggx452
TNO identifier
787776
Publisher
Oxford University Press
ISSN
0956-540X
Source
Geophysical Journal International, 212 (3), 1487-1497
Article number
ggx452
Document type
article