Laboratory study of self-potential signals during releasing of CO2 and N2 plumes

Vieira, Cristian; Maineult, Alexis; Zamora, Maria

doi:10.1016/j.crte.2012.09.002

Cited by 5 publications

(4 citation statements)

References 28 publications

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“…Allègre et al (2014) suggested that C increases and then decreases during progressive water desaturation. In fact, laboratory experiments on SP in unsaturated media are difficult to realize because (i) experiments may not be easily reproducible due to the complex behavior of gas in porous media; (ii) the SP amplitude may vary with the size of the electrode used for the measurements (Vieira et al, 2012), (iii) signal instabilities due to bad contacts can be generated at the electrode scale; (iv) the low amplitude of the SP renders the signal difficult to measure. Water condensation/evaporation at the rock/fluid interface may also influence the measurements.…”

Section: Sp In Unsaturated Porous Mediamentioning

confidence: 99%

“…The SP was thought to be induced by the relative motion between the solid phase (porous material) and the water droplets in suspension in the gaseous phase is then invoked. Vieira et al (2012) shown in his experiments that the amplitude of the electrical potentials increases above an injection of gas (CO 2 ) within a sandbox. Although the amount of gas could not be quantified from signals, injection timespan and increasing of injection rate were identified by the SP method.…”

Section: Sp In Unsaturated Porous Mediamentioning

confidence: 99%

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Electric potential anomaly induced by humid air convection within Piton de La Fournaise volcano, La Réunion Island

et al. 2017

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a b s t r a c tSelf potential (SP) anomalies over Piton de La Fournaise volcano (La Réunion Island) are generally inter-preted as resulting from meteoritic water porous flow. However, there is no clear evidence that the subsurface is permanently saturated. Recently, a convective subsurface airflow has been evidenced within a quiescent cone at Piton de La Fournaise (Formica Leo). SP and thermal anomalies are reported on the unsaturated edifice and are seen to be correlated. It is proposed that the SP signal is generated by the movement of water films present on the porous matrix, induced by the intense humid airflow within Formica Leo. The structure of the cone, determined from electrical resistivity tomography (ERT), ground penetrating radar (GPR), microgravimetric and kinematic GPS data, is used to constrain a 3D numerical model of the air convection. The calculated temperature is then used to derive the related SP signal, the electrokinetic coupling coefficient being estimated from direct observations of the electrical resistivity of the soil. Extrapolating these results to the scale of the volcano, it is thus proposed that a cold humid air-flow enters the flanks of the 400 m-high terminal dome, flows up along the sloped and stratified volcanic layers before exiting through the vertical fractures around the Dolomieu collapse. It is demonstrated that the SP anomalies catches the main features recovered over the entire volcano. This result strongly sug-gests that humid airflow may play a major role on the generation of SP anomalies at Piton de la Fournaise volcano, and perhaps in other unsaturated volcanic edifices.

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Section: Sp In Unsaturated Porous Mediamentioning

confidence: 99%

Section: Sp In Unsaturated Porous Mediamentioning

confidence: 99%

Electric potential anomaly induced by humid air convection within Piton de La Fournaise volcano, La Réunion Island

et al. 2017

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“…These electrodes are connected to a multichannel voltmeter characterized by a high impedance (>10 MΩ) and a high sensitivity (0.1 mV). Due to its low cost and its high sensitivity to the groundwater flow, the self‐potential method has been used to infer fluid dynamic properties (e.g., Ikard et al, 2012; Jardani et al, 2009; Rizzo et al, 2004), to characterize hydrogeological parameters (e.g., Jardani & Revil, 2009; Ozaki et al, 2014; Straface et al, 2011), to monitor fluid movement processes such as tracer or seawater migration (e.g., Graham et al, 2018; Jougnot et al, 2015; MacAllister et al, 2018; Vieira et al, 2012), and to detect groundwater contaminants (e.g., Abbas et al, 2017; Mao et al, 2015; Minsley et al, 2007; Naudet et al, 2003). For instance, Minsley et al (2007) employed the SP method to detect a DNAPL contaminated site and their result showed that the SP sources can serve as a good indicator of contaminated area, but only if the contaminants are actively biodegrading under favorable conditions.…”

Section: Introductionmentioning

confidence: 99%

Improved Characterization of DNAPL Source Zones via Sequential Hydrogeophysical Inversion of Hydraulic‐Head, Self‐Potential and Partitioning Tracer Data

Kang

Kokkinaki

Kitanidis

et al. 2020

Water Resources Research

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High‐resolution characterization of hydraulic properties and dense nonaqueous phase liquid (DNAPL) contaminant source is crucial to develop efficient remediation strategies. However, DNAPL characterization suffers from a limited number of borehole data in the field, resulting in a low‐resolution estimation. Moreover, high‐resolution DNAPL characterization requires a large number of unknowns to be estimated, presenting a computational bottleneck. In this paper, a low‐cost geophysical approach, the self‐potential method, is used as additional information for hydraulic properties characterization. Joint inversion of hydraulic head and self‐potential measurements is proposed to improve hydraulic conductivity estimation, which is then used to characterize the DNAPL saturation distribution by inverting partitioning tracer measurements. The computational barrier is overcome by (a) solving the inversion by the principal component geostatistical approach, in which the covariance matrix is replaced by a low‐rank approximation, thus reducing the number of forward model runs; (b) using temporal moments of concentrations instead of individual concentration data points for faster forward simulations. To assess the ability of the proposed approach, numerical experiments are conducted in a 3‐D aquifer with 104 unknown hydraulic conductivities and DNAPL saturations. Results show that with realistic DNAPL sources and a limited number of hydraulic heads, the traditional hydraulic/partitioning tracer tomography roughly reconstructs subsurface heterogeneity but fails to resolve the DNAPL distribution. By adding self‐potential data, the error is reduced by 24% in hydraulic conductivity estimation and 68% in DNAPL saturation characterization. The proposed sequential inversion framework utilizes the complementary information from multi‐source hydrogeophysical data sets, and can provide high‐resolution characterizations for realistic DNAPL sources.

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“…SP can also be used to monitor enhanced oil and gas recovery (Gulamali et al, ; Jackson et al, ) and to characterize oil and gas reservoirs, including to better understand reservoir wettability (Alroudhan et al, ; Alroudhan et al, ; Jackson et al, ). It has also been applied to studies of CO 2 sequestration (Vieira et al, ) and in geothermal applications (Darnet et al, ; Jardani et al, ; Revil et al, ).…”

Section: Introductionmentioning

confidence: 99%

Characterizing the Self‐Potential Response to Concentration Gradients in Heterogeneous Subsurface Environments

et al. 2019

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Self‐potential (SP) measurements can be used to characterize and monitor, in real‐time, fluid movement and behavior in the subsurface. The electrochemical exclusion‐diffusion (EED) potential, one component of SP, arises when concentration gradients exist in porous media. Such concentration gradients are of concern in coastal and contaminated aquifers and oil and gas reservoirs. It is essential that estimates of EED potential are made prior to conducting SP investigations in complex environments with heterogeneous geology and salinity contrasts, such as the UK Chalk coastal aquifer. Here we report repeatable laboratory estimates of the EED potential of chalk and marls using natural groundwater (GW), seawater (SW), deionized (DI) water, and 5 M NaCl. In all cases, the EED potential of chalk was positive (using a GW/SW concentration gradient the EED potential was ca. 14 to 22 mV), with an increased deviation from the diffusion limit at the higher salinity contrast. Despite the relatively small pore size of chalk (ca. 1 μm), it is dominated by the diffusion potential and has a low exclusion efficiency, even at large salinity contrasts. Marl samples have a higher exclusion efficiency which is of sufficient magnitude to reverse the polarity of the EED potential (using a GW/SW concentration gradient the EED potential was ca. −7 to −12 mV) with respect to the chalk samples. Despite the complexity of the natural samples used, the method produced repeatable results. We also show that first order estimates of the exclusion efficiency can be made using SP logs, supporting the parameterization of the model reported in Graham et al. (2018, https://doi.org/10.1029/2018WR022972), and that derived values for marls are consistent with the laboratory experiments, while values derived for hardgrounds based on field data indicate a similarly high exclusion efficiency. While this method shows promise in the absence of laboratory measurements, more rigorous estimates should be made where possible and can be conducted following the experimental methodology reported here.

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Laboratory study of self-potential signals during releasing of CO2 and N2 plumes

Cited by 5 publications

References 28 publications

Electric potential anomaly induced by humid air convection within Piton de La Fournaise volcano, La Réunion Island

Electric potential anomaly induced by humid air convection within Piton de La Fournaise volcano, La Réunion Island

Improved Characterization of DNAPL Source Zones via Sequential Hydrogeophysical Inversion of Hydraulic‐Head, Self‐Potential and Partitioning Tracer Data

Characterizing the Self‐Potential Response to Concentration Gradients in Heterogeneous Subsurface Environments

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