Aquistore: Performance Monitoring for Full-Chain CCS – April 2015 Cranfield Biannual

This blog was written by Eni Oko, a UKCCSRC ECR from the University of Hull, who received funding from the ECR Meeting Fund to attend the UKCCSRC Spring 2015 Biannual in Cranfield, 21-22 April. 

Microseismic monitoring at the Aquistore CCS site – Anna Stork (University of Bristol)

Anna is presently a post-doctoral research assistant in the School of Earth Sciences at University of Bristol with focus on monitoring and understanding seismic activity associated with fluid injection. She obtained MPhys in physics from University of Manchester in 2000, MSc in geophysics from Durham University in 2001 and DPhil in earthquake location methods from University of Oxford in 2007. Her previous work was on microseismic data from the In Salah CCS project. This presentation is drawn from her current work in the Aquistore project where she is investigating the microseismic response to injection at the site.

In this presentation, Anna highlighted the importance of microseismic monitoring at the Aquistore site where some of the CO₂ captured from the adjacent capture site at Boundary Dam Power Plant, Saskatchewan, Canada is to be stored as part of the Boundary Dam CCS Project. Monitoring program involves both surface and downhole monitoring. Detected seismic events can be used to verify geomechanical models and provide real-time early warning of CO₂ migration or leakage. Collection of baseline data at the site using geophones (>10 Hz) has been going on since July, 2012 with three broadband seismometers (0.1 – 50 Hz) added in 2013 which cover an area of about 2.5 km x 2.5 km surrounding the injection well.

So far, preliminary analysis of baseline data show noise which has been linked to activities at the power plant, around the wells and on nearby roads. Event detection, location and magnitude estimation procedures has been calibrated using injection well perforation shots and reported regional events. The results from the seismic data analysis will be used to characterise any induced seismicity associated with CO₂ injection.

Passive noise analysis from the permanent surface array at the Aquistore CCS site – Claire Birnie (University of Leeds)

Claire is a postgraduate research student in the Institute Applied of Geosciences at the University of Leeds. Her research focuses on characterisation and implementation of seismic noise within a synthetic reservoir full-waveform microseismic dataset. She gained BSc in Geophysics and Meteorology at the University of Edinburgh with competencies in VSP data processing, well log data handling and VSP modelling.

In this presentation, Claire discussed passive noise analysis of passive seismic data collected at the Aquistore injection site in 2012 over a three-month period. The aim is to identify and characterise individual noise sources prior to their recreation within a synthetic dataset and to thereafter create a realistic noise model with spatial and temporal variations as identified from the noise in the collected data. Noise classification schemes which systematically represents the temporal and spatial variations and trends will be defined on the course of the research.

Preliminary analysis of noise signals identified at the Aquistore injection site have been carried out. The signals were classified via scheme defined into the noise categories: stationary, non-stationary and pseudo-non-stationary noise. Developing mathematical description of the signals is planned. This will focus on non-stationary and non-linear aspects with the aim to build a synthetic seismic dataset as realistic noise. 

Fingerprinting captured CO₂ using natural tracers at Aquistore – Stuart Gilfillan (University of Edinburgh)

Stuart is a Chancellor’s Fellow in Geochemistry in the School of Geosciences at the University of Edinburgh. He has had experience working on potential of CO₂ storage in depleted natural gas reservoirs over millions of years and more recently working on tracers for CO₂ monitoring within CO₂ storage sites and as early warning tracers of CO₂ leakage.  He carried out noble gas tracing in the SECARB Cranfield Stacked Storage experiment at the Cranfield oil field in Mississippi and was involved in the IPAC-CO₂ independent investigation into the alleged CO₂ leakage event on the Kerr property near Weyburn.

In this presentation, Stuart highlighted fingerprinting of captured CO₂ as a way of establishing storage security which is crucial to the success of CCS and looks at the option using natural tracers such as carbon and oxygen stable isotopes and noble gas for fingerprinting captured CO₂. Artificial tracers are expensive and could pose a hazard to the environment. The aim is to determine if fingerprints of CO₂ captured using different capture technologies or from different fossil fuels are distinctive enough to track the CO₂ once they are injected underground without the need for artificial tracers and if they are enough to distinguish ownership of CO₂ injected into the same storage sites.

This is achieved by determining the fingerprint of CO₂ captured from the Boundary Dam Power Plant prior to its injection into the Aquistore saline aquifer storage site in Saskatchewan, Canada.  It will then be determined if the fingerprint is retained after the CO₂ has moved through the saline aquifer by comparing the fingerprint to the fingerprint of the CO₂ produced from the Aquistore monitoring well. From the results, it can be shown if this technique is suitable for tracking the movement of CO₂ in future storage sites.