The effect of free-phase NAPL on the spectral induced polarization signature of variably saturated soil

Shefer, Idit; Schwartz, Nimrod; Furman, Alex

doi:10.1002/wrcr.20502

Cited by 20 publications

(19 citation statements)

References 43 publications

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“…For example, Shefer et al (2013) presented a conceptual model of these conditions, where the NAPL was, as we understand it, assumed to create rings around air-filled pores by displacement of the water phase.…”

Section: Discussionmentioning

confidence: 99%

“…In published research, interpretation of IP data often rely on different conceptual models of NAPL configuration, which in different ways explain the observed results (e.g. Olhoeft, 1985;Titov et al, 2004;Martinho et al, 2006;Schmutz et al, 2010;Revil et al, 2011;Flores Orozco et al, 2012;Shefer et al, 2013). However, to date, there are no comparative studies discussing possible effects of different models.…”

Section: Introductionmentioning

confidence: 95%

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Influence of non-aqueous phase liquid configuration on induced polarization parameters: Conceptual models applied to a time-domain field case study

Johansson

Fiandaca

Dahlin

2015

Journal of Applied Geophysics

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Resistivity and induced polarization (IP) measurements on soil contaminated with non-aqueous phase liquids (NAPLs) show a great variety in results in previous research. Several laboratory studies have suggested that the presence of NAPLs in soil samples generally decrease the magnitude of the IP-effect, while others have indicated the opposite. A number of conceptual models have been proposed suggesting that NAPLs can alter the pore space in different ways, e.g. by coating the grain surfaces and thus inhibiting grain polarization, or by changing the pore throat size and thus affecting the membrane polarization mechanism. The main aim of this paper is to review previously published conceptual models and to introduce some new concepts of possible residual NAPL configurations in the pore space. Time domain induced polarization measurements were performed at a NAPL contaminated field site, and the data were inverted using the Constant Phase Angle (CPA) model and the Cole-Cole model respectively. No significant phase anomalies were observed in the source area of the contamination when the CPA inverted profiles were compared with soil sampling results of free-phase contaminant concentrations. However, relatively strong phase and normalized phase anomalies appeared next to the source area, where residual free-phase presence could be expected according to the chemical data. We conclude that depending on the NAPL configuration, different spectral IP responses can be expected. In previous research, the NAPL configurations in different samples or field sites are often unknown, and this may to some extent explain why different results have been achieved by different authors. In our field case, we believe that the NAPL forms a more or less continuous phase in the pore space of the source zone leading to an absence of IP anomalies. The increase in phase and normalized phase angle observed next to the source zone is interpreted as a degradation zone. The ongoing biodegradation may have led to a fractionation of the continuous NAPL in the outer part of the original source zone, leading to residual presence of isolated NAPL droplets in the soil pores. With such NAPL configurations, an increased polarization can be expected according to the electrochemical-and membrane polarization mechanisms. More research is needed to confirm the effects of different NAPL configuration on spectral IP parameters.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Influence of non-aqueous phase liquid configuration on induced polarization parameters: Conceptual models applied to a time-domain field case study

Johansson

Fiandaca

Dahlin

2015

Journal of Applied Geophysics

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“…Considerable effort has been devoted to developing noninvasive, geophysical methods for detecting NAPL distributions. These methods have included using time domain reflectometry [Persson and Berndtsson, 2002], measuring self-potential signals [Minsley et al, 2007], using nuclear magnetic resonance measurements [Bryar and Knight, 2008], and applying the spectral induced polarization technique Shefer et al [2013]. Revil and Mahardika [2013] demonstrated that seismoelectric effects could be used to identify the position of a NAPL-water encroachment front.…”

Section: Field Studies Of Napl Flow and Entrapmentmentioning

confidence: 99%

Organic contaminant transport and fate in the subsurface: Evolution of knowledge and understanding

Essaid

Bekins

Cozzarelli

2015

Water Resources Research

148

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Toxic organic contaminants may enter the subsurface as slightly soluble and volatile nonaqueous phase liquids (NAPLs) or as dissolved solutes resulting in contaminant plumes emanating from the source zone. A large body of research published in Water Resources Research has been devoted to characterizing and understanding processes controlling the transport and fate of these organic contaminants and the effectiveness of natural attenuation, bioremediation, and other remedial technologies. These contributions include studies of NAPL flow, entrapment, and interphase mass transfer that have advanced from the analysis of simple systems with uniform properties and equilibrium contaminant phase partitioning to complex systems with pore-scale and macroscale heterogeneity and rate-limited interphase mass transfer. Understanding of the fate of dissolved organic plumes has advanced from when biodegradation was thought to require oxygen to recognition of the importance of anaerobic biodegradation, multiple redox zones, microbial enzyme kinetics, and mixing of organic contaminants and electron acceptors at plume fringes. Challenges remain in understanding the impacts of physical, chemical, biological, and hydrogeological heterogeneity, pore-scale interactions, and mixing on the fate of organic contaminants. Further effort is needed to successfully incorporate these processes into field-scale predictions of transport and fate. Regulations have greatly reduced the frequency of new point-source contamination problems; however, remediation at many legacy plumes remains challenging. A number of fields of current relevance are benefiting from research advances from point-source contaminant research. These include geologic carbon sequestration, nonpoint-source contamination, aquifer storage and recovery, the fate of contaminants from oil and gas development, and enhanced bioremediation.

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“…; Kemna et al . ; Shefer, Schwartz, and Furman ). In addition, several authors have studied the influence of fluid saturation on complex impedance (Vinegar and Waxman ; Ulrich and Slater ; Titov et al .…”

Section: Introductionmentioning

confidence: 99%

“…Using equivalent circuit theory, the induced polarisation can be related to the coupling between the components of capacitance and resistance. It has been suggested that the physical mechanism of induced polarisation is related to the electrical double layer and membrane polarisation at lower frequencies and the Maxwell-Wagner polarisation at higher frequencies (Chelidze and Gueguen 1999;Chen and Or 2006;Revil and Florsch 2010;Jougnot et al 2010;Kemna et al 2012;Shefer, Schwartz, and Furman 2013). In addition, several authors have studied the influence of fluid saturation on complex impedance (Vinegar and Waxman 1984;Ulrich and Slater 2004;Titov et al 2004;Binley et al 2005;Cassiani et al 2009;Xiao et al 2009;Jougnot et al 2010;Schmutz et al 2010;Kavian, Slob, and Mulder 2012;Schmutz, Blondel, and Revil 2012;Su, Feng, and Shang 2000).…”

mentioning

confidence: 99%

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

Zhang

Park

Nishizawa

et al. 2016

Geophysical Prospecting

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To better understand the effect of fluid distribution on the electric response of rocks saturated with oil and brine, we conducted experimental studies on the complex electrical impedance in a Berea sandstone, together with in situ acquisitions of oil distribution images employing a high‐resolution medical X‐ray computed tomography. We performed two tests of brine displacement by oil under high (10 MPa) and low (5 MPa) pressures, which were accompanied by fingering and stable displacement patterns, respectively. The measured complex impedance data were fitted to the Cole model to obtain the resistance, capacitance, peak frequency of the imaginary impedance, and the exponent α of the rock–fluid system. With increasing oil saturation, the resistance showed an increasing trend, whereas the other three parameters decreased. The fingering displacement exhibited lower resistance and capacitance than the stable displacement. The analysis of the resistance changes using a simple parallel connection model indicates that there are more components of residual brine in parallel connections in the fingering pattern than in the stable displacement pattern at the same saturation. We also interpreted the normalised changes in the capacitance (or apparent dielectric constant) with respect to the oil saturation via an analysis of the shape factor of fluid distribution based on the Maxwell–Wagner–Brugermann–Hanai model. The changes in the shape factor suggest that the pinch‐off of the brine in parallel connection by the oil is a dominant mechanism reducing the capacitance. In the stable displacement, most of the connections in the brine phase are immediately pinched off by oil displacement front at a local oil saturation of 65%. Conversely, in the fingering displacement, there is a transition from the bulk or layered brine to the pinched‐off at a local oil saturation below 60%. The analyses indicate that the difference in the fluid distribution under different fluid conditions is responsible for the non‐Archie behaviour.

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The effect of free-phase NAPL on the spectral induced polarization signature of variably saturated soil

Cited by 20 publications

References 43 publications

Influence of non-aqueous phase liquid configuration on induced polarization parameters: Conceptual models applied to a time-domain field case study

Influence of non-aqueous phase liquid configuration on induced polarization parameters: Conceptual models applied to a time-domain field case study

Organic contaminant transport and fate in the subsurface: Evolution of knowledge and understanding

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

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The effect of free-phase NAPL on the spectral induced polarization signature of variably saturated soil

Cited by 20 publications

References 43 publications

Influence of non-aqueous phase liquid configuration on induced polarization parameters: Conceptual models applied to a time-domain field case study

Influence of non-aqueous phase liquid configuration on induced polarization parameters: Conceptual models applied to a time-domain field case study

Organic contaminant transport and fate in the subsurface: Evolution of knowledge and understanding

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 104–106 Hz

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Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz