Managing the remediation strategy of contaminated megasites using field-scale calibration of geo-electrical imaging with chemical monitoring

Lévy, Léa; Bording, Thue S.; Fiandaca, Gianluca; Christiansen, Anders Vest; Madsen, Line M.; Bennedsen, Lars F.; Jørgensen, Torben Højbjerg; MacKinnon, Leah; Christensen, Jørgen F.

doi:10.1016/j.scitotenv.2024.171013

Cited by 1 publication

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“…While many applications of geophysics focus on structural characterization using static geophysical data (Binley et al, 2015), time-lapse geophysics provides a promising avenue to characterize the spatial distribution and temporal evolution of transport and reaction processes (Hermans et al, 2023). So far, most of the field applications of time-lapse geophysics have focused on characterizing flow and transport processes: groundwatersurface water interaction (Slater et al, 2010), water absorption by roots (Jayawickreme et al, 2010;Mary et al, 2020), migration of methane plume (Steelman et al, 2017), migration of injected remediation agent at contaminated site (Flores Orozco et al, 2015;Lévy et al, 2024). Monitoring reactive processes with time-lapse geophysics remains challenging and a very limited number of field cases exist (see e.g., reviews by Binley et al (2015) and Hermans et al (2023)).…”

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confidence: 99%

Understanding the Fate of H₂S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging

Lévy,

Ciraula,

Legros

et al. 2024

JGR Solid Earth

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To help meet emission standards, hydrogen sulfide (H2S) from geothermal production may be injected back into the subsurface, where basalt offers, in theory, the capacity to mineralize H2S into pyrite. Ensuring the viability of this pollution mitigation technology requires information on how much H2S is mineralized, at what rate and where. To date, monitoring efforts of field‐scale H2S reinjection have mostly occurred via mass balance calculations, typically capturing less than 5% of the injected fluid. While these studies, along with laboratory experiments and geochemical models, conclude effective H2S mineralization, their extrapolation to quantify mineralization and its persistence over time leads to considerable uncertainty. Here, a geophysical methodology, using time‐domain induced polarization (TDIP) logging in two of the injection wells (NN3 and NN4), is developed as a complementary tool to follow the fate of H2S re‐injected at Nesjavellir geothermal site (Iceland). Results show a strong chargeability increase at +40 days, interpreted as precipitation of up to 2 vol.% based on laboratory relationships. A uniform increase is observed along NN4, whereas it is localized below 450 m in NN3. Changes are more pronounced with larger electrode spacing, indicating that pyrite precipitation takes place away from the wells. Furthermore, a chargeability decrease is observed at later monitoring rounds in both wells, suggesting that pyrite is either passivated or re‐dissolved after precipitating. These results highlight that a sequence of overlapping reactive processes (pyrite precipitation, passivation, pore clogging and possibly pyrite re‐dissolution) results from H2S injection and that TDIP monitoring is sensitive to this sequence.

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Section: Introductionmentioning

confidence: 99%

Understanding the Fate of H₂S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging

Lévy,

Ciraula,

Legros

et al. 2024

JGR Solid Earth

View full text Add to dashboard Cite

show abstract

Managing the remediation strategy of contaminated megasites using field-scale calibration of geo-electrical imaging with chemical monitoring

Cited by 1 publication

References 61 publications

Understanding the Fate of H₂S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging

Understanding the Fate of H₂S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging

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Managing the remediation strategy of contaminated megasites using field-scale calibration of geo-electrical imaging with chemical monitoring

Cited by 1 publication

References 61 publications

Understanding the Fate of H2S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging

Understanding the Fate of H2S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging

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Understanding the Fate of H₂S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging

Understanding the Fate of H₂S Injected in Basalts by Means of Time‐Domain Induced Polarization Geophysical Logging