Pre-injection magnetotelluric surveys at the Aquistore CO₂ sequestration site, Estevan, Saskatchewan, Canada.

McLeod, Joe; Ferguson, Ian M.; Craven, Jim; Roberts, Brian et Giroux, Bernard ORCID: https://orcid.org/0000-0002-2042-2759 (2018). Pre-injection magnetotelluric surveys at the Aquistore CO₂ sequestration site, Estevan, Saskatchewan, Canada. International Journal of Greenhouse Gas Control , vol. 74 . pp. 99-118. DOI: 10.1016/j.ijggc.2018.04.024.

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Résumé

Magnetotelluric (MT) soundings were conducted in a 4 × 4 km area at the Aquistore CO₂ sequestration site at Estevan, Saskatchewan, Canada in 2013, 2014 and 2015, prior to CO₂ injection. The MT response is locally one-dimensional but spatially variable at short periods (<0.01 s), regionally one-dimensional at intermediate periods (0.01 s to 10 s), and two-dimensional at long periods (>30 s). Responses corresponding to Williston Basin rocks are uniform across the area. A representative MT response was inverted using constraints derived from a resistivity well-log. Beneath the Jurassic Watrous to Vanguard formations (at depths greater than 1240–1600 m), the resistivity of the inversion model is consistently 20–30% lower than in the reference well-log model, consistent with the MT method sensing the longitudinal resistivity of the more strongly stratified units at these depths. Electromagnetic noise in the MT data set includes high-frequency odd harmonics of the 60 Hz source and a broad-band source, spatially associated with the CO₂ pipeline, observed only in 2014. Within the period range 10⁻⁴ to 10² s, but outside the bands influenced by the broad-band noise, the off-diagonal MT impedance response at Aquistore can be measured with an RMS repeatability of 1% or better.

Type de document:	Article
Mots-clés libres:	aquistore; CO₂ sequestration; pre-injection; geophysics; magnetotelluric
Centre:	Centre Eau Terre Environnement
Date de dépôt:	08 juin 2018 19:46
Dernière modification:	08 févr. 2022 20:26
URI:	https://espace.inrs.ca/id/eprint/7281

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