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 M. V. Gilfillan

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

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 water is the result of isotope equilibrium exchange between residual CO2 and water. For the region further away from the well, the isotopic shift in the reservoir water can also be explained by isotopic exchange with mobile CO2 from ahead of the region driven to residual, or continuous isotopic exchange between water and residual CO2 during its back-production, complicating the interpretation of the change in reservoir water δ18O in terms of residual saturation. A small isotopic distinction of the baseline water and CO2 δ18O, together with issues encountered during the field experiment procedure, further prevents the estimation of residual CO2 saturation levels from oxygen isotope changes without significant uncertainty. The similarity of oxygen isotope-based near-wellbore saturation levels and independent estimates based on pulsed neutron logging indicates the potential of using oxygen isotope as an effective inherent tracer for determining residual saturation on a field scale within a few days.
LanguageEnglish
Pages73-83
Number of pages11
JournalInternational Journal of Greenhouse Gas Control
Volume52
Early online date9 Jul 2016
DOIs
Publication statusPublished - 30 Sep 2016

Fingerprint

Isotopes
oxygen isotope
saturation
Oxygen
isotope
trapping
Water
oxygen isotope ratio
Neutron logging
water exchange
water
Radioactive tracers
Carbon capture
tracer
test
aquifer
Aquifers
water reservoir
carbon
Experiments

Keywords

  • residual saturation
  • oxygen isotopes
  • Otway
  • geochemical tracer
  • CO2 storage

Cite this

Serno, Sascha ; Johnson, Gareth ; LaForce, Tara C. ; Ennis-King, Jonathan ; Haese, Ralf R. ; Boreham, Christopher J. ; Paterson, Lincoln ; Freifeld, Barry M. ; Cook, Paul J. ; Kirste, Dirk ; Haszeldine, R. Stuart ; Gilfillan, Stuart M. V. / Using oxygen isotopes to quantitatively assess residual CO2 saturation during the CO2CRC otway stage 2B extension residual saturation test. In: International Journal of Greenhouse Gas Control . 2016 ; Vol. 52. pp. 73-83.
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title = "Using oxygen isotopes to quantitatively assess residual CO2 saturation during the CO2CRC otway stage 2B extension residual saturation test",
abstract = "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 water is the result of isotope equilibrium exchange between residual CO2 and water. For the region further away from the well, the isotopic shift in the reservoir water can also be explained by isotopic exchange with mobile CO2 from ahead of the region driven to residual, or continuous isotopic exchange between water and residual CO2 during its back-production, complicating the interpretation of the change in reservoir water δ18O in terms of residual saturation. A small isotopic distinction of the baseline water and CO2 δ18O, together with issues encountered during the field experiment procedure, further prevents the estimation of residual CO2 saturation levels from oxygen isotope changes without significant uncertainty. The similarity of oxygen isotope-based near-wellbore saturation levels and independent estimates based on pulsed neutron logging indicates the potential of using oxygen isotope as an effective inherent tracer for determining residual saturation on a field scale within a few days.",
keywords = "residual saturation, oxygen isotopes, Otway, geochemical tracer, CO2 storage",
author = "Sascha Serno and Gareth Johnson and LaForce, {Tara C.} and Jonathan Ennis-King and Haese, {Ralf R.} and Boreham, {Christopher J.} and Lincoln Paterson and Freifeld, {Barry M.} and Cook, {Paul J.} and Dirk Kirste and Haszeldine, {R. Stuart} and Gilfillan, {Stuart M. V.}",
note = "This work is part of the project {"}Quantifying Residual and Dissolution Trapping in the CO2CRC Otway Injection Site{"}, funded by UKCCSRC as a Call 2 project. The grant number is UKCCSRC-C2-204. Main PI: Stuart Gilfillan.",
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Serno, S, Johnson, G, LaForce, TC, Ennis-King, J, Haese, RR, Boreham, CJ, Paterson, L, Freifeld, BM, Cook, PJ, Kirste, D, Haszeldine, RS & Gilfillan, SMV 2016, 'Using oxygen isotopes to quantitatively assess residual CO2 saturation during the CO2CRC otway stage 2B extension residual saturation test' International Journal of Greenhouse Gas Control , vol. 52, pp. 73-83. https://doi.org/10.1016/j.ijggc.2016.06.019

Using oxygen isotopes to quantitatively assess residual CO2 saturation during the CO2CRC otway stage 2B extension residual saturation test. / Serno, Sascha; Johnson, Gareth; LaForce, Tara C.; Ennis-King, Jonathan; Haese, Ralf R.; Boreham, Christopher J.; Paterson, Lincoln; Freifeld, Barry M.; Cook, Paul J.; Kirste, Dirk; Haszeldine, R. Stuart; Gilfillan, Stuart M. V.

In: International Journal of Greenhouse Gas Control , Vol. 52, 30.09.2016, p. 73-83.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Using oxygen isotopes to quantitatively assess residual CO2 saturation during the CO2CRC otway stage 2B extension residual saturation test

AU - Serno, Sascha

AU - Johnson, Gareth

AU - LaForce, Tara C.

AU - Ennis-King, Jonathan

AU - Haese, Ralf R.

AU - Boreham, Christopher J.

AU - Paterson, Lincoln

AU - Freifeld, Barry M.

AU - Cook, Paul J.

AU - Kirste, Dirk

AU - Haszeldine, R. Stuart

AU - Gilfillan, Stuart M. V.

N1 - This work is part of the project "Quantifying Residual and Dissolution Trapping in the CO2CRC Otway Injection Site", funded by UKCCSRC as a Call 2 project. The grant number is UKCCSRC-C2-204. Main PI: Stuart Gilfillan.

PY - 2016/9/30

Y1 - 2016/9/30

N2 - 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 water is the result of isotope equilibrium exchange between residual CO2 and water. For the region further away from the well, the isotopic shift in the reservoir water can also be explained by isotopic exchange with mobile CO2 from ahead of the region driven to residual, or continuous isotopic exchange between water and residual CO2 during its back-production, complicating the interpretation of the change in reservoir water δ18O in terms of residual saturation. A small isotopic distinction of the baseline water and CO2 δ18O, together with issues encountered during the field experiment procedure, further prevents the estimation of residual CO2 saturation levels from oxygen isotope changes without significant uncertainty. The similarity of oxygen isotope-based near-wellbore saturation levels and independent estimates based on pulsed neutron logging indicates the potential of using oxygen isotope as an effective inherent tracer for determining residual saturation on a field scale within a few days.

AB - 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 water is the result of isotope equilibrium exchange between residual CO2 and water. For the region further away from the well, the isotopic shift in the reservoir water can also be explained by isotopic exchange with mobile CO2 from ahead of the region driven to residual, or continuous isotopic exchange between water and residual CO2 during its back-production, complicating the interpretation of the change in reservoir water δ18O in terms of residual saturation. A small isotopic distinction of the baseline water and CO2 δ18O, together with issues encountered during the field experiment procedure, further prevents the estimation of residual CO2 saturation levels from oxygen isotope changes without significant uncertainty. The similarity of oxygen isotope-based near-wellbore saturation levels and independent estimates based on pulsed neutron logging indicates the potential of using oxygen isotope as an effective inherent tracer for determining residual saturation on a field scale within a few days.

KW - residual saturation

KW - oxygen isotopes

KW - Otway

KW - geochemical tracer

KW - CO2 storage

U2 - 10.1016/j.ijggc.2016.06.019

DO - 10.1016/j.ijggc.2016.06.019

M3 - Article

VL - 52

SP - 73

EP - 83

JO - International Journal of Greenhouse Gas Control

T2 - International Journal of Greenhouse Gas Control

JF - International Journal of Greenhouse Gas Control

SN - 1750-5836

ER -