Can induced polarization be used to monitor hydrocarbon plume flow in soils?
Abstract
Since the beginning of the industrial era, petroleum hydrocarbons are becoming a global problem for the environment, especially when spilled. They can persistently contaminate soil and rock formations, are toxic for the fauna and flora and present health risks to humans. It is crucial to monitor these hydrocarbon plume evolution over time, both in terms of localization and state. Geophysical methods, in complement to classical soil water sampling and analysis, offer good spatial and temporal resolutions to monitor hydrocarbon dynamics. The induced polarization (IP) method is both sensitive to bulk and interfacial properties and thus offers a unique tool to investigate environmentally impacted sites. Indeed, IP could be used to monitor the hydrocarbon plume movement as well as degradation. While it is proven that IP measurements are influenced by the presence of hydrocarbon, the mechanisms leading to these changes are yet unclear. Studies are even observing contrasting variations, partially explained by the variety of hydrocarbons themselves and the mixed additives that can be polar.
We studied the IP signature of jet fuel flow in columns filled with three different types of soils containing various amounts of clays. Each soil has a different polarization frequency. We focused on monitoring the variation of the IP signature around this relaxation frequency. In the three soils, we observe a decrease of the real and imaginary conductivities during the jet fuel injection. The phase shift behavior is varying depending on the soil type. It can increase or be stable, depending on the soil type. We thus recommend monitoring the imaginary conductivity rather than the phase shift to detect hydrocarbon plume flow. Using these results, we estimate transport and degradation constants that could be used as first guesses in hydrological transport models.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H21H1806K
- Keywords:
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- 1829 Groundwater hydrology;
- HYDROLOGY;
- 1835 Hydrogeophysics;
- HYDROLOGY;
- 1865 Soils;
- HYDROLOGY;
- 1899 General or miscellaneous;
- HYDROLOGY