Self-potential: A low-cost geophysical method in investigating groundwater and contaminant plume

The main landfill in the city of Rabat (Morocco) is based on sandy material containing the shallow Mio-Pliocene aquifer. The presence of a pollution plume is likely, but its extent is not known. Measurements of spontaneous potential (SP) from the soil surface were cross-referenced with direct measurements of the water table and leachates (pH, redox potential, electrical conductivity) according to the available accesses, as well as with an analysis of the landscape and the water table flows. With a few precautions during data acquisition on this resistive terrain, the results made it possible to separate the electrokinetic (~30%) and electrochemical (~70%) components responsible for the range of potentials observed (70 mV). The plume is detected in the hydrogeological downstream of the discharge, but is captured by the natural drainage network and does not extend further under the hills.

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Microbial ecology and geoelectric responses across a groundwater plume

Interpretation ◽

10.1190/int-2015-0058.1 ◽

2015 ◽

Vol 3 (4) ◽

pp. SAB9-SAB21 ◽

Cited By ~ 2

Author(s):

Rory Doherty ◽

Blathnaid McPolin ◽

Bernd Kulessa ◽

Alessandra Frau ◽

Anna Kulakova ◽

...

Keyword(s):

Microbial Ecology ◽

Large Scale ◽

Contaminant Plume ◽

Electrochemical Gradient ◽

Iron Cycling ◽

Nitrogen Gas ◽

Nitrite Nitrate ◽

Redox Boundary ◽

Self Potential

We have used geophysics, microbiology, and geochemistry to link large-scale (30+ m) geophysical self-potential (SP) responses at a groundwater contaminant plume with its chemistry and microbial ecology of groundwater and soil from in and around it. We have found that microbially mediated transformation of ammonia to nitrite, nitrate, and nitrogen gas was likely to have promoted a well-defined electrochemical gradient at the edge of the plume, which dominated the SP response. Phylogenetic analysis demonstrated that the plume fringe or anode of the geobattery was dominated by electrogens and biodegradative microorganisms including Proteobacteria alongside Geobacteraceae, Desulfobulbaceae, and Nitrosomonadaceae. The uncultivated candidate phylum OD1 dominated uncontaminated areas of the site. We defined the redox boundary at the plume edge using the calculated and observed electric SP geophysical measurements. Conductive soils and waste acted as an electronic conductor, which was dominated by abiotic iron cycling processes that sequester electrons generated at the plume fringe. We have suggested that such geoelectric phenomena can act as indicators of natural attenuation processes that control groundwater plumes. Further work is required to monitor electron transfer across the geoelectric dipole to fully define this phenomenon as a geobattery. This approach can be used as a novel way of monitoring microbial activity around the degradation of contaminated groundwater plumes or to monitor in situ bioelectric systems designed to manage groundwater plumes.

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Groundwater redox conditions and conductivity in a contaminant plume from geoelectrical investigations

Hydrology and Earth System Sciences ◽

10.5194/hess-8-8-2004 ◽

2004 ◽

Vol 8 (1) ◽

pp. 8-22 ◽

Cited By ~ 136

Author(s):

V. Naudet ◽

A. Revil ◽

E. Rizzo ◽

J.-Y. Bottero ◽

P. Bégassat

Keyword(s):

Electrical Conductivity ◽

Electrical Resistivity ◽

Redox Potential ◽

Linear Correlation ◽

Electrical Resistivity Tomography ◽

The Self ◽

Contaminant Plume ◽

Resistivity Tomography ◽

Self Potential ◽

Good Linear Correlation

Abstract. Accurate mapping of the electrical conductivity and of the redox potential of the groundwater is important in delineating the shape of a contaminant plume. A map of redox potential in an aquifer is indicative of biodegradation of organic matter and of concentrations of redox-active components; a map of electrical conductivity provides information on the mineralisation of the groundwater. Both maps can be used to optimise the position of pumping wells for remediation. The self-potential method (SP) and electrical resistivity tomography (ERT) have been applied to the contaminant plume associated with the Entressen landfill in south-east France. The self-potential depends on groundwater flow (electrokinetic contribution) and redox conditions ("electro-redox" contribution). Using the variation of the piezometric head in the aquifer, the electrokinetic contribution is removed from the SP signals. A good linear correlation (R2=0.85) is obtained between the residual SP data and the redox potential values measured in monitoring wells. This relationship is used to draw a redox potential map of the overall contaminated site. The electrical conductivity of the subsoil is obtained from 3D-ERT analysis. A good linear correlation (R2=0.91) is observed between the electrical conductivity of the aquifer determined from the 3D-ERT image and the conductivity of the groundwater measured in boreholes. This indicates that the formation factor is nearly homogeneous in the shallow aquifer at the scale of the ERT. From this correlation, a map of the pore water conductivity of the aquifer is obtained. Keywords: self-potential, redox potential, electrical resistivity tomography, fluid conductivity, contaminant plume

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Bulk meltwater flow and liquid water content of snowpacks mapped using the electrical self-potential (SP) method

The Cryosphere ◽

10.5194/tc-10-433-2016 ◽

2016 ◽

Vol 10 (1) ◽

pp. 433-444 ◽

Cited By ~ 2

Author(s):

Sarah S. Thompson ◽

Bernd Kulessa ◽

Richard L. H. Essery ◽

Martin P. Lüthi

Keyword(s):

Electrical Conductivity ◽

Water Content ◽

Liquid Water ◽

Low Cost ◽

Sensor Arrays ◽

Ground Truth ◽

Liquid Water Content ◽

Potential Method ◽

Avalanche Forecasting ◽

Self Potential

Abstract. Our ability to measure, quantify and assimilate hydrological properties and processes of snow in operational models is disproportionally poor compared to the significance of seasonal snowmelt as a global water resource and major risk factor in flood and avalanche forecasting. We show here that strong electrical self-potential fields are generated in melting in situ snowpacks at Rhone Glacier and Jungfraujoch Glacier, Switzerland. In agreement with theory, the diurnal evolution of self-potential magnitudes ( ∼  60–250 mV) relates to those of bulk meltwater fluxes (0–1.2  ×  10−6 m3 s−1) principally through the permeability and the content, electrical conductivity and pH of liquid water. Previous work revealed that when fresh snow melts, ions are eluted in sequence and electrical conductivity, pH and self-potential data change diagnostically. Our snowpacks had experienced earlier stages of melt, and complementary snow pit measurements revealed that electrical conductivity ( ∼  1–5  ×  10−6 S m−1) and pH ( ∼  6.5–6.7) as well as permeabilities (respectively ∼  9.7  ×  10−5 and ∼  4.3  ×  10−5 m2 at Rhone Glacier and Jungfraujoch Glacier) were invariant. This implies, first, that preferential elution of ions was complete and, second, that our self-potential measurements reflect daily changes in liquid water contents. These were calculated to increase within the pendular regime from ∼  1 to 5 and ∼  3 to 5.5 % respectively at Rhone Glacier and Jungfraujoch Glacier, as confirmed by ground truth measurements. We conclude that the electrical self-potential method is a promising snow and firn hydrology sensor owing to its suitability for (1) sensing lateral and vertical liquid water flows directly and minimally invasively, (2) complementing established observational programs through multidimensional spatial mapping of meltwater fluxes or liquid water content and (3) monitoring autonomously at a low cost. Future work should focus on the development of self-potential sensor arrays compatible with existing weather and snow monitoring technology and observational programs, and the integration of self-potential data into analytical frameworks.

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On: “The electrochemical mechanics of sulfide self‐potentials” by M. Sato and H. M. Mooney (GEOPHYSICS, 25, 226-249, February 1960)

Geophysics ◽

10.1190/1.1442034 ◽

1986 ◽

Vol 51 (1) ◽

pp. 194-196 ◽

Cited By ~ 3

Author(s):

S. V. Burr

Keyword(s):

The Self ◽

Geophysical Method ◽

Important Paper ◽

Field Information ◽

Self Potential ◽

Additional Field

I was recently introduced to this very important paper on the self potential. Realizing the paper is 25 years old, additional field information is now available, and that others have probably responded with critiques, nevertheless, I choose to report my experiences with this trustworthy, sorely neglected, geophysical method.

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Self-potential monitoring of a salt plume

Geophysics ◽

10.1190/1.3475533 ◽

2010 ◽

Vol 75 (4) ◽

pp. WA17-WA25 ◽

Cited By ~ 31

Author(s):

P. Martínez-Pagán ◽

A. Jardani ◽

A. Revil ◽

A. Haas

Keyword(s):

Real Time ◽

Current Density ◽

Potential Method ◽

The Self ◽

Contaminant Plume ◽

Salty Water ◽

Source Current ◽

Self Potential ◽

Over Time ◽

Source Current Density

Nonintrusively monitoring the spread of contaminants in real time with a geophysical method is an important task in hydrogeophysics. We have developed a sandbox experiment showing that the self-potential method can locate both the source of leakage and the front of a contaminant plume. We monitored the leakage of a plume of salty water from a hole at the bottom of a small tank located at the top of a main sandbox. Initially, the sand was saturated by tap water. At a given time, a hole was opened at the bottom of the tank, allowing the salty water to migrate by diffusion and buoyancy-driven flow in the main sandbox. The bottom of the sandbox contained a network of 32 nonpolarizing silver-silver chloride electrodes with amplifiers, connected to a multichannel voltmeter. The self-potential response associated withthe migration of the salt plume in the sandbox was recorded over time. A self-potential anomaly was observed with amplitude varying from a few millivolts at the start of the leak to a few tens of millivolts after a few minutes. The self-potential data were inverted using a time-lapse tomographic algorithm to reconstruct the position of the volumetric source current density over time. A positive volumetric source current density was associated with the position of the leak at the bottom of the leaking tank, whereas a negative volumetric source current density was associated with the salinity front moving down inside the sandbox. These poles were well reproduced by performing a finite-element simulation of the problem. Using this information, we estimated the speed of the salt plume sinking inside the sandbox. Therefore, the self-potential method can be used to track, in real time, the position of the front of a contaminant plume in a porous material.

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Is there any room for gravity in petroleum exploration? Let's open the door again!

The APPEA Journal ◽

10.1071/aj19195 ◽

2020 ◽

Vol 60 (2) ◽

pp. 761

Author(s):

Sergey Shevchenko

Keyword(s):

Oil And Gas ◽

Gravity Data ◽

Low Cost ◽

Petroleum Industry ◽

Oil And Gas Industry ◽

Petroleum Exploration ◽

Geophysical Method ◽

Gas Industry ◽

Gravity Method ◽

1960S And 1970S

The seismic method has been thriving in the oil and gas industry for decades. Technological progress in acquisition, processing and interpretation have made it practically the only geophysical method used for petroleum exploration. Unfortunately, gravity, as a pioneering geophysical method appears to have been completely forgotten in Australia’s oil and gas industry. Most of the gravity data in Australia were collected in the 1960s and 1970s. Only government agencies and a few exploration companies have conducted gravity surveys in petroleum basins since that time. Australia’s mostly flat terrain, economical aspects of the gravity method such as low cost and the ability to cover vast underexplored onshore basins in the country, all seem to be positive factors indicating that this method should be commonly used as a part of petroleum exploration. Given the petroleum industry is currently trying hard to make exploration more economically effective, this may be an opportunity to revive the gravity method in petroleum exploration.

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Self-potential (SP) generated by electrokinesis – Efficiency and low cost dam safety

Journal of Applied Geophysics ◽

10.1016/j.jappgeo.2020.104122 ◽

2020 ◽

Vol 180 ◽

pp. 104122

Author(s):

José Domingos Faraco Gallas

Keyword(s):

Low Cost ◽

Dam Safety ◽

Self Potential

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A PRACTICAL APPROACH FOR SELF-POTENTIAL DATA ACQUISITION, PROCESSING, AND VISUALIZATION

Interpretation ◽

10.1190/int-2020-0012.1 ◽

2020 ◽

pp. 1-67

Author(s):

Stéphanie Barde-Cabusson ◽

Anthony Finizola ◽

Niels Grobbe

Keyword(s):

Data Acquisition ◽

Survey Design ◽

Low Cost ◽

Hydrothermal Systems ◽

Natural Environments ◽

Design Data ◽

Robust Processing ◽

Data Acquisition And Processing ◽

Self Potential ◽

Acquisition Method

We propose a comprehensive methodology for the acquisition and processing of self-potential (SP) data, as well as some keys to the interpretation of the results. The wide applicability of the SP method, and its low cost, make it a popular method for use in a variety of natural environments. Despite its versatility and the fact that various published journal papers describe the method and its applications, we believe that there is an important need for a dedicated, peer-reviewed SP acquisition, processing and visualization/interpretation paper in the scientific literature. We identified a great interest from the scientific community for such a journal paper as a guide for both existing and new practitioners with their SP survey design, data acquisition, robust processing, and initial interpretation steps. A step-by-step methodology is proposed here for SP data acquisition and processing, combined with practical guidance for the interpretation of collected and processed SP data, including a discussion of common errors and typical sources of uncertainty. The presented examples are based on studies in volcanic environments (e.g. hydrothermal systems), however the processing steps and methodology are fully applicable and transferable across disciplines to SP data acquired in any environment, and for a wide variety of applications. After a short overview of the field acquisition method and the low-cost equipment, the reference and closure corrections, their meaning for the SP signal, and their effect on the dataset are detailed and exemplified. The benefits of interpolating SP data in two steps is discussed. Combining map visualization, SP vs distance, and SP vs elevation graphs appears as a highly effective strategy to interpret the signal in terms of hydrogeological and hydrothermal domains, and to highlight structural limits in volcanic contexts as well as in other environments.

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Self-potential monitoring for hydrologic investigations in urban covered-karst terrain

Geophysics ◽

10.1190/geo2013-0354.1 ◽

2014 ◽

Vol 79 (6) ◽

pp. B231-B242 ◽

Cited By ~ 6

Author(s):

Peter B. Bumpus ◽

Sarah E. Kruse

Keyword(s):

Surface Sediments ◽

Low Cost ◽

Flow Regimes ◽

Karst Terrain ◽

Conduit Flow ◽

Lower Permeability ◽

Soil Conductivity ◽

Covered Karst ◽

Cultural Noise ◽

Self Potential

In the covered karst of west-central Florida, USA, sinkholes (sandy collapse conduits) provide locally concentrated recharge to underlying aquifers. For water management, it would be beneficial to understand the rates at which collapse conduits recharge an underlying aquifer. Self-potential (SP) monitoring has promise as a noninvasive, relatively low-cost method for assessing temporal variability in flow. Previous studies suggested that negative SP anomalies over collapse conduits correspond to downward-flowing groundwater; however, before SP surveys can be reliable indicators of conduit flow, SP from ET, soil conductivity changes, redox, electrode effects, and cultural noise must be better understood. A year of continuous SP monitoring with two grids of approximately 15 Pb/PbCl/KCl nonpolarizing electrodes each was combined with high-resolution ground-penetrating radar surveys and intermittent water table monitoring over two small covered-karst conduits in Tampa, Florida, USA. Although variations in SP resulting from changes in cultural noise, soil conductivity, ET, redox, and rainfall were evident, separate and unrelated positive and negative SP anomalies episodically manifested over conduits, which suggested that conduit flow could be dynamic, not static. Three flow regimes in conduits were postulated: conduit permeability higher than in surrounding surficial sediments, conduit permeability lower than in surrounding surface sediments, conduit permeability matched surrounding surface sediments. Numerical steady-state 2D simulations in Comsol created the three postulated flow regimes and revealed that a different SP polarity could result from different rates of flow: positive SP corresponded to higher permeability conduits, negative SP corresponded to lower permeability conduits, no or minimal SP appeared when conduits and surrounding sediments had equal permeability. In these models, downward flow was not responsible for generating negative SP. To assess the hydrology of a conduit, it appears that SP should be monitored continuously. Further monitoring of field sites with hydrologic sensors is needed.

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