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Communication dans un congrès

Limits, complementarity and improvement of Advanced SAR Interferometry monitoring of anthropogenic subsidence/uplift due to long term CO2 storage

Abstract : A prerequisite to the large scale industrial development of CO2 Capture and geological Storage is the demonstration that the storage is both efficient and safe. In this context, precise uplift/subsidence monitoring techniques constitute a key component of any CO2 storage risk management. Space-borne Differential SAR (Synthetic Aperture Radar) interferometry is a promising monitoring technique. It can provide valuable information on vertical positions of a set of scatterer undergoing surface deformation induced by volumetric changes through time and space caused by CO2 injection in deep aquifers. To what extent ? To date, InSAR techniques have been successfully used in a variety of case-studies involving the measure of surface deformation caused by subsurface fluid withdrawal / injection. For instance, groundwater flow characterization in complex aquifers systems, oil / gas field characterization, verification of enhanced oil recovery efficiency, monitoring of seasonal gas storage. The successful use of InSAR is strictly related to the favourable scattering conditions in terms of spatial distribution of targets and their temporal stability. In arid regions, natural radar scatterers density can be very high, exceeding 1,000 per km². But future onshore industrial-scale CO2 storage sites are planned in more complex land-covers such as agricultural or vegetated terrains. Those terrains are characterized by poor to moderate radar scatterers density, which decrease the detection limits of the space-borne interferometric technique. The present study discusses the limits and constraints of advanced InSAR techniques applied to deformation measurements associated with CO2 injection/storage into deep aquifers in the presence of agricultural and vegetated land-covers. We explore different options to enhance the measurement performances of InSAR techniques. As a first option, we propose to optimize the deployment of a network of "artificial" scatterers, i.e. corner reflectors (artificial devices installed on ground to provide high backscatter to the radar signal) to complement the existing "natural" network. The methodology is iterative and adaptive to the spatial and temporal extent of the detectable deforming region. We take into account the need of a change in sensors characteristics (for a very long term monitoring 10-50 years) that could result in a need of re-organisation of the network. Our discussion is supported by the estimates of the expected spatio-temporal evolution of surface vertical displacements caused by CO2 injection at depth by combining the approximate analytical solutions for pressure build-up during CO2 injection in deep aquifers and the poro-elastic behaviour of the reservoir under injection. As second option, we then review different advanced InSAR algorithms that could improve the displacement measurements using natural scatterers over vegetated areas.
keyword : Sar interferometry
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https://hal-brgm.archives-ouvertes.fr/hal-00912855
Contributeur : Marcello de Michele <>
Soumis le : lundi 2 décembre 2013 - 17:00:35
Dernière modification le : mardi 31 mars 2020 - 10:46:09

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  • HAL Id : hal-00912855, version 1

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Marcello de Michele, Jeremy Rohmer, Daniel Raucoules, Annick Loschetter, Y. Le Gallo,, et al.. Limits, complementarity and improvement of Advanced SAR Interferometry monitoring of anthropogenic subsidence/uplift due to long term CO2 storage. AGU Fall meeting 2013, Dec 2013, San Francisco, United States. pp.à suivre. ⟨hal-00912855⟩

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