Is CO2 injection at Aquistore aseismic? A combined seismological and geomechanical study of early injection operations

A. L. Stork*, C. G. Nixon, C. D. Hawkes, C. Birnie, D. J. White, D. R. Schmitt, B. Roberts

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Fluid injection is known to induce seismic events if the injection causes fracturing of the surrounding rock or if resulting pressure changes reactivate pre-existing faults and fractures. Carbon dioxide (CO2) storage projects where CO2 is injected into deep geological formations for permanent containment are one sector where induced seismicity has been observed. The Aquistore storage project in Saskatchewan, Canada began CO2 injection into the basal Cambrian sandstone at ∼3.2 km deep in April 2015 and the site has been extensively monitored for seismicity. Passive seismic monitoring instrumentation includes a small network of broadband seismometers, a continuously recording array of near-surface geophones and temporary deployments of downhole geophones at depths from 2950 m to 3010 m in an observation well. To date no injection-related induced seismicity has been observed. The seismic arrays are functioning as expected and local mine blasts, orientation shots and perforation shots have been detected using standard detection algorithms. Data stacking algorithms have also been tested on short-periods of data. Using synthetic data added to noise models, the estimated minimum detectable event local magnitude is −0.8 for the broadband stations and between −1.6 and −0.6 for the near-surface geophones. Thus far, small volumes of CO2 have been injected at Aquistore (∼140 kt) and injection has generally occurred below the fracture pressure. As a result, predicted pore pressure changes are small and periods without injection have allowed relaxation of the pressure plume. Geomechanical modelling suggests insignificant effective stress changes at an identified fault near the Aquistore injection well. It is therefore not surprising that no induced seismicity has been detected. With further injection, continued seismic monitoring is essential to provide warning of any fault reactivation and thus any potential increase in seismic risk or CO2 leakage risk.

Original languageEnglish (US)
Pages (from-to)107-124
Number of pages18
JournalInternational Journal of Greenhouse Gas Control
Volume75
DOIs
StatePublished - Aug 2018

Bibliographical note

Funding Information:
The authors gratefully acknowledge the Petroleum Technology Research Centre’s (PTRC’s) Aquistore Project for its support and collaboration on this research. ALS acknowledges the financial support of the UK CCS Research Centre ( www.ukccsrc.ac.uk ) in carrying out this work. The UKCCSRC is funded by the EPSRC as part of the RCUK Energy Programme ( EP/K000446/1 ). ALS thanks the Bristol University Microseismicity Projects (BUMPS) sponsors for supporting this research. Third party data was used in this study. Access to the geophone array data can be applied for from PTRC. The broadband station data is available from NRCan. We thank two anonymous reviewers for their comments that helped improve this manuscript. This is Geological Survey of Canada contribution 20180037.

Publisher Copyright:
© 2018 The Authors

Keywords

  • Aquistore
  • Carbon Capture and Storage (CCS)
  • Geomechanics
  • Passive seismic monitoring

ASJC Scopus subject areas

  • Pollution
  • General Energy
  • Management, Monitoring, Policy and Law
  • Industrial and Manufacturing Engineering

Fingerprint

Dive into the research topics of 'Is CO2 injection at Aquistore aseismic? A combined seismological and geomechanical study of early injection operations'. Together they form a unique fingerprint.

Cite this