Journal article

Using oxygen isotopes to quantitatively assess residual CO2 saturation during the CO2CRC Otway Stage 2B Extension residual saturation test

Sascha Serno, Gareth Johnson, Tara C LaForce, Jonathan Ennis-King, Ralf R Haese, Christopher J Boreham, Lincoln Paterson, Barry M Freifeld, Paul J Cook, Dirk Kirste, R Stuart Haszeldine, Stuart MV Gilfillan



Residual CO2 trapping is a key mechanism of secure CO2 storage, an essential component of the Carbon Capture and Storage technology. Estimating the amount of CO2 that will be residually trapped in a saline aquifer formation remains a significant challenge. Here, we present the first oxygen isotope ratio (δ18O) measurements from a single-well experiment, the CO2CRC Otway 2B Extension, used to estimate levels of residual trapping of CO2. Following the initiation of the drive to residual saturation in the reservoir, reservoir water δ18O decreased, as predicted from the baseline isotope ratios of water and CO2, over a time span of only a few days. The isotope shift in the near-wellbore reservoir..

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Awarded by EPSRC

Awarded by NERC

Awarded by Engineering and Physical Sciences Research Council

Awarded by Natural Environment Research Council

Funding Acknowledgements

This work was supported by funding from the UK CCS Research Centre (UKCCSRC) through the Call 2 grant to S.M.V.G., GJ. and R.S.S., and the ECR International Travel Exchange Fund to S.S. The UKCCSRC is funded by the EPSRC as part of the RCUK Energy Programme. Funding for the Otway 2B Extension comes through CO2CRC, AGOS and COSPL. The authors acknowledge the funding provided by the Australian government through its CRC programme to support this CO2CRC research project. C.J.B. publishes with the permission of the CEO, Geoscience Australia. Funding for the group from the Lawrence Berkeley National Laboratory was provided by the Carbon Storage Program, U.S. DOE, Assistant Secretary for Fossil Energy, Office of Clean Coal and Carbon Management through the NETL. We would like to thank Sue Golding and Kim Baublys for conducting stable isotope measurements at the Stable Isotope Geochemistry Laboratory of the School of Earth Sciences, University of Queensland, Australia. We appreciate the help in sample collection from Jay Black, Hong Phuc Vu and the field operating team under the supervision of Rajindar Singh. The paper was improved by constructive comments from two anonymous reviewers.