What can the GeoSuite App Do

Defining fracture networks

Fracturing of the geology containing aquifer systems plays a major role in the eventual success of any groundwater exploration project. Fractures can greatly enhance the flow rates of any production well. As such they need to be located and defined for maximum benefit.   

The GeoSuite App provides the user with tools to locate and define fracture networks as well as functions to help describe the geological context of these fracture networks.

Defining fresh and saline aquifer systems

As not all the water under the ground is fresh, the GeoSuite App includes data sets that help differentiate between fresh and saline groundwater sources. This is very important in water supply projects where the aim is to sustainably supply fresh water to a community without unacceptably risking saline contamination of the few freshwater aquifers available.

Data Sets Produced

Electro-Seismic Investigation

Hydraulic Conductivity Tomography (ESKT)

The ESKT data shows the relative, inferred, electro seismic hydraulic conductivity tomography data results for the test site sounding profile. As the data has not been calibrated to an absolute field reference point, at which the hydraulic conductivity, with depth, is absolutely known. It is described as a normalized, relative, inferred, hydraulic conductivity value ranging from 0 to 100%. The maximum normalized value, shown on the ESKT profile as 100%, is determined by assigning the maximum recorded hydraulic conductivity value for the site a value of 100%. All other values are normalized against this value.

Electro Seismic Coupling Coefficient Tomography (ESCCT)

The ESCCT data shows the relative, inferred, electro seismic coupling coefficient tomography data for the sounding profile. The ESCCT data describes the normalized, relative, coupling efficiency for the conversion of the seismic pressure wave to the resultant electro-magnetic wave field. The data is expressed as a normalized percentage of the maximum recorded conversion efficiency.

The ESCCT data can be used to indicate a number site specific variables, including:

1)       Pore fluid electrical conductivity variability;

2)       Pore fluid acidity variability;

3)       Pore fluid temperature variability;

4)       Pore fluid viscosity variability;

5)       Zeta Potential.

The properties that affect the ESCCT data response are site specific and must be viewed and interpreted in context.

Fracture Analysis (ESFT)

The ESFT data shows the relative, inferred, bedding plain fracture zone depths. The electro seismic data is spectrally analyzed and specific frequency patterns associated with fracturing are used to infer bedding plane fracturing. The results are used to describe possible secondary permeability features. These fractured zones are generally associated with higher fluid flow rates.

There are a number of geological features that could produce indications of a fracture indicator response. These include

1)       Geological interfaces or interfacial responses;

2)       Quartz bearing formations;

3)       Beading plain fractures;

4)       Ferrite bearing formations;

5)       Sulphide bearing formations.

A reasonable understanding of the site geology and correlating neighbouring point data is required to accurately interpret ESFT data.

If the pressure wave does intersect a real fracture, a response will only be produced by a near horizontal fracture. Any fracture with a dip of 30 degrees or more is generally not seen, as they do not develop a strong response.

Interface Tomography (ESIT)

The ESIT data indicate the positions of interfaces between formations with differing electrical and elastic properties. It makes use of the unique interfacial effects generated, by electro seismic conversion, as the pressure wave passes through a formation change.

The ESIT data shown is representative of all the detected interface responses, irrespective of amplitude. Thus strong and weak reflectors are shown as equally weighted responses. This is done to highlight any geological features that may be missed if viewed in context of reflector strength. The data does show the total gradient polarity of the reflector. A blue response is a negative polarity reflector and red is a positive polarity reflector.

Electro-Seismic Interface Angular Response Tomography (ESIAT)

The ESIAT data represents the change in angular gradient that occurs at the interface between two formations with differing electrical or elastic properties. This data is response amplitude dependent as the gradient of the response in front and behind the interface are amplitude dependent, however, changes in formations with similar electrical or elastic property changes will have similar angular gradient change responses. This allows for the characterization of interfaces between independent sounding locations. This will allow for the correlation of inter-point interfaces to determine the position and depth of major geological changes.

Electro-Seismic Interface Angular Normalised Response Tomography (ESIANT)

The ESIANT data set is the normalized version of the ESIAT data set. The normalization of the ESIAT data set is done to minimise the effects of ES response amplitude which may affect the calculation of pre and post response gradient calculations. This effectively improves the correlation of ESIAT between individual sounding locations. This allows for improved characterization of interfaces between independent sounding locations. And improves the interpretation of the position and depth of major geological changes.

Electro-Seismic Change in Absolute Response Tomography (ESCAGT)

The ESCAGT data set is the relative, inferred indication of the absolute Zeta potential, or Electro kinetic potential, of a geological formation. Zeta potential is defined as the potential difference generated by the ionic charge separation between the ions at the slipping plain of the separation double layer, as referenced to a point within the pore space fluid far away from the double layer. An illustration of this is shown in Figure 12.

The Zeta potential is commonly used as a measure of charge. As such, the Zeta potential is a defining electrical characteristic of any given geological formation and can be used to characterize formation changes or similarities.

In the case of ESCAGT data sets, the values shown are for the absolute calculation of the Zeta potentials magnitude. Thus any negative values are ignored. This allows for the analysis of Zeta potential data from a purely magnitude based point of view.

The data is expressed as the normalised, relative, absolute response gradient of the ES field with a maximum value of 100% and a minimum value of 0%.

Electro-Seismic Change in Total Response Tomography (ESCTGT)

The ESCTGT data set is the relative, inferred indication of the total Zeta potential, or Electro kinetic potential, of a geological formation. Zeta potential is defined as the potential difference generated by the ionic charge separation between the ions at the slipping plain of the separation double layer, as referenced to a point within the pore space fluid far away from the double layer. An illustration of this is shown in Figure 12.

The Zeta potential is commonly used as a measure of charge. As such, the Zeta potential is a defining electrical characteristic of any given geological formation and can be used to characterize formation changes or similarities.

In the case of ESCAGT data sets, the values shown are for the total calculation of the Zeta potentials. Thus any negative values are included. This allows for the analysis of Zeta potential data from a total field point of view including both magnitude and polarity information. As the Zeta potential for most fully saturated geological formations with pore space fluid that has electrolyte content is inherently negative in value, most of the ESCTGT will be negative in value. An exception to this can be found in the unconsolidated materials that overly the saturated consolidated geological formations. These formations generally are slightly positive in nature. This positive Zeta potential data can be used to define this unconsolidated material and is useful at determining the thickness and extent of unconsolidated topsoil’s under a survey site.

The ESCTGT data is expressed as the normalised, relative, total response gradient of the ES field with a maximum value of 100% and a minimum value of -100%.

Electro-Seismic Groundwater Flow Potential Tomography (ESGFPT)

The ESGFPT indicates the most likely position for groundwater flow. It combines all the relevant electrical and hydrological ES response data of the formations under the site to determine the normalised relative inferred percentage of probability of groundwater flow. It is important to note that the data represented is not an indication of the absolute probability of groundwater flow, but rather the most likely locations, or locations with the best possibility, of groundwater flow, when compared to all the other ES locations surveyed.

The ESCTGT data is expressed as the normalised, relative, potential for groundwater flow with a maximum value of 100% and a minimum value of 0%.

It must be clearly understood that a value of 100% ESGFPT probability is not and should not be interpreted as a 100% reality of locating high flowing groundwater. It is only an estimated indicator of where the most likely position for groundwater flow might be located under the surveyed site.

Electro-Seismic Fractures associated with Interfaces Tomography (ESFIT)

The ESFIT data is the representation of the correlation between the ESIT data and the ESFT data sets. This data effectively delineates fracturing indicators that exist at the interfaces between changes of geological formations. This data effectively defines interfacial fracturing and provides insight into the secondary permeability nature of any given geological interface.

The ESFIT data is expressed as the normalised, relative, probability of fracturing with a maximum value of 100% and a minimum value of -100%.

Electro-Seismic Fractures associated with Hydraulic Conductivity Tomography (ESFKT)

The ESFKT data is the representation of the correlation between the ESKT data and the ESFT data sets. This data effectively delineates fracturing indicators that exist within primary permeability formations or aquifers. This allows for the analysis of probable high flow groundwater sources within aquifer systems that are facilitated by secondary permeability flow paths.

The ESFKT data is expressed as the normalised, relative, probability of fracturing within a primary permeability formation with a maximum value of 100% and a minimum value of 0%.

Electro-Seismic Fractures associated with Ground Water Flow Potential Tomography (ESFGFPT)

The ESFGFPT data is the representation of the correlation between the ESGFPT data and the ESFT data sets. This data effectively delineates fracturing indicators that exist within calculated, high probability of groundwater flow, aquifers. This allows for the analysis of probable high flow groundwater sources within aquifer systems that are facilitated by secondary permeability flow paths.

The ESFKT data is expressed as the normalised, relative, probability of fracturing within a high probability groundwater flow formation with a maximum value of 100% and a minimum value of 0%.

Electro-Seismic Coupling Coefficient Change in Absolute Response Gradient Tomography (ESCCCAGT)

The ESCCCAGT data is the representation of the correlation between the ESCCT data and the ESCAGT data sets. This data effectively delineates formations with both high ES coupling efficiencies and high Zeta Potential characteristics. This data is useful at delineating formations which have high coupling efficiencies with strong Zeta potential electrical characteristics. This helps evaluate whether ES coupling efficiency is dominated by Zeta potential or by one of the other properties that control ES coupling efficiency, such as:

1)       Pore fluid electrical conductivity variability;

2)       Pore fluid acidity variability;

3)       Pore fluid temperature variability;

4)       Pore fluid viscosity variability.

The ESCCCAGT data is expressed as the normalised, relative, probability of the presence of a formation with both high coupling efficiency and high Zeta Potential with a maximum value of 100% and a minimum value of 0%.

Electro-Seismic Coupling Coefficient Change in Total Response Gradient Tomography (ESCCCTGT)

The ESCCCTGT data is the representation of the correlation between the ESCCT data and the ESCTGT data sets. This data effectively delineates formations with both high ES coupling efficiencies and high Zeta Potential characteristics. This data is useful at delineating formations which have high coupling efficiencies with strong Zeta potential electrical characteristics. This helps evaluate whether ES coupling efficiency is dominated by Zeta potential or by one of the other properties that control ES coupling efficiency, such as:

5)       Pore fluid electrical conductivity variability;

6)       Pore fluid acidity variability;

7)       Pore fluid temperature variability;

8)       Pore fluid viscosity variability.

The difference between the ESCCCTGT and the ESCCCAGT data sets is that the ESCCCTGT data set includes the polarity of the Zeta Potential, as well as the magnitude, where the ESCCCAGT includes only the magnitude of the Zeta potential. This allows for the evaluation of coupling efficiency effects within the unconsolidated topsoil coving a site.

The ESCCCTGT data is expressed as the normalised, relative, probability of the presence of a formation with both high coupling efficiency and high Zeta Potential with a maximum value of 100% and a minimum value of -100%.

Electro-Telluric Investigation

Electro-telluric Tomography (ET)

The ET data set describes the variability in conductivity of the formations under a site. The data set does not describe the apparent conductivity of the formations underlying a site as it is only a representation of the potential difference generated by a streaming current as it passes through a conductive medium. As such the full ohms law equation cannot be applied as the magnet field amplitude of the streaming current is absent. That said, the data does indicate variability in conductivity which can be used to delineate conductive formations even though the exact conductivity cannot be determined without calibration against a resistivity downhole well log.

The ET data set is generated by frequency analysis of the background noise on the site, for a pre-determined period of time, to a maximum frequency of 10Hz. The frequency domain data is analysed for amplitude to determine the variability of conductivity for the formations at specific depths under the site.

This data set is not linear in resolution. Resolution decrease exponentially from surface level to depth. It is very important that interpretations of conductive formations at depth consider this lower vertical resolution limitation.

The ET data is expressed as the normalised, relative, variability in formation electrical conductivity with a maximum value of 100% and a minimum value of 0%.

Electro-telluric Gradient Tomography (ETGT)

The ETGT data set describes the gradient of variability in conductivity of the formations under a site. This data allows for the delineation of formations with similar variability in conductivity gradient. As such, it is used to refine lithological unit interpretations for a specific site geology.

The ETGT data is expressed as the normalised, relative, variability in formation electrical conductivity gradient with a maximum value of 100% and a minimum value of -100%.

Electro-telluric Interface Tomography (ETIT)

The ETIT data set describes the position and depths of interface indicators that occur at the boundaries between two geological units with differing electrical conductivity variability. This data allows for the delineation of ET generated interfaces data. This effectively allows for the interpretation of lithological units under the site from an ET point of view. This data is very useful as a comparative data set to correlate the similar ESIT data sets too.

The ETIT data is expressed as the normalised, relative, probability of an interface with a maximum value of 100% and a minimum value of -100%.

Electro-telluric Interface Angular Response Tomography (ETIAT)

The ETIAT data represents the change in angular gradient of electrical conductivity variability that occurs at the interface between two formations with differing electrical properties. This data is response amplitude dependent as the gradient of the response in front and behind the interface are amplitude dependent, however, changes in formations with similar electrical conductivity properties changes will have similar angular gradient change responses. This allows for the characterization of interfaces between independent sounding locations. This will allow for the correlation of inter-point interfaces to determine the position and depth of major geological changes.

The ETIAT data is expressed as the normalised, relative, probability of an interface with a maximum value of 100% and a minimum value of -100%.

Electro-telluric Interface Angular Normalised Response Tomography (ETIANT)

The ETIANT data set is the normalized version of the ETIAT data set. The normalization of the ETIAT data set is done to minimise the effects of ET response amplitude which may affect the calculation of pre and post response gradient calculations. This effectively improves the correlation of ETIAT between individual sounding locations. This allows for improved characterization of interfaces between independent sounding locations. And improves the interpretation of the position and depth of major geological changes.

The ETIANT data is expressed as the normalised, relative, probability of an interface with a maximum value of 100% and a minimum value of -100%.

Electro-Seismo-Telluric Investigation

10.1 Electro-Telluric Electro-Seismic Hydraulic Conductivity Tomography (ETESKT)

The ETESKT data is the representation of the correlation between the ESKT and ET data sets. It allows for the analysis of high hydraulic conductivity formations in relation to their perceived conductivity variability. In most cases, higher conductivity formations are associated with groundwater bearing aquifer systems. When a higher conductivity formation correlates well with a high level of hydraulic conductivity, the probability that the formation is a high permeability water saturated aquifer is high. As such this data set is useful at improving the interpretation of aquifer systems.

As the conductivity variability of a geological is related to the salinity of the formation pore space fluid, a formation with a high level of salinity will also have a higher electrical conductivity variation. This means that the ETESKT data can also be used to determine if a particular aquifer system is saline or not.

The ETESKT data is expressed as the normalised, relative, aquifer probability with a maximum value of 100% and a minimum value of 0%.

Electro-Telluric Electro-Seismic Coupling Coefficient Tomography (ETESCCT)

The ETESCCT data is the representation of the correlation between the ESCCT and ET data sets. It allows for the analysis of a geological formations ES coupling efficiency in terms of its correlation to the electrical conductivity variability. This data is used to determine whether a particular high conductivity formation is high in electrical conductivity variability due to the influence of high ES coupling efficiency, which is determined by the following parameters:

1)       Pore fluid electrical conductivity variability;

2)       Pore fluid acidity variability;

3)       Pore fluid temperature variability;

4)       Pore fluid viscosity variability;

5)       Zeta Potential.

This data set plays and important role in the interpretation of the electrical characteristics of a given formation and pore space fluid.

The ETESCCT data is expressed as the normalised, relative, correlation index between the ESCCT and ET data sets with a maximum value of 100% and a minimum value of 0%.

Electro-Telluric Electro-Seismic Change in Absolute Response Gradient Tomography (ETESCAGT)

The ETESCAGT data is the representation of the correlation between the ESCAGT and ET data sets. It allows for the analysis of ES Zeta Potential as it correlates to ET electrical conductivity variability for a particular geological formation. This is important as the ETESCCT data indicates the ES coupling efficiency correlation, as a whole, to the electrical conductivity variability of the formation. This does not allow for the determination of whether an increased ES coupling efficiency is due to formation conductivity or if it is due to factors that affect the pore space fluid, such as salinity, PH or viscosity. The ETESCAGT data, however, targets only the Zeta Potential of the formation which is directly coupled to the formation chargeability and does not relate to the electrical properties of the pore space fluid. This allows for the determination of whether a formation electrical conductivity variability is due to the rock matric electrical properties or if it is due to variations in the pore space fluid electrical properties.

The ETESCAGT data is expressed as the normalised, relative, correlation index between the ESCAGT and ET data sets with a maximum value of 100% and a minimum value of 0%.

Electro-Telluric Electro-Seismic Groundwater Flow Potential Tomography (ETESGFPT)

The ETESGFPT data is the representation of the correlation between the ESGFPT and ET data sets. It allows for the analysis of the correlation between formations with high calculated probability of groundwater flow and the electrical conductivity variability of said formations.

This data helps improve the interpretation of the ESGFPT data sets by correlating them to high conductivity variability data, which is a strong indicator of groundwater saturated formations.

The ETESGFPT data is expressed as the normalised, relative, correlation index between the ESGFPT and ET data sets with a maximum value of 100% and a minimum value of 0%.

Electro-Telluric Electro-Seismic Coupling Coefficient Change in Absolute Response Gradient Tomography (ETESCCCAGT)

The ETESCCCAGT data is the representation of the correlation between the ESCCCAGT and ET data sets.

The ESCCCAGT evaluate whether ES coupling efficiency is dominated by Zeta potential or by one of the other properties that control ES coupling efficiency.

The ETESCCCAGT data set expands on this by allowing for the delineation of formations with high electrical conductivity caused by high coupling efficiencies due to high formation Zeta potentials. This data set effectively represents an enhanced interpretation of the ETESCAGT data set, in that it includes the ES coupling efficiency data in the correlation index calculation.

The ETESGFPT data is expressed as the normalised, relative, correlation index between the ESCCT, ESCAGT and ET data sets with a maximum value of 100% and a minimum value of 0%.

Electro-Telluric Electro-Seismic Groundwater Flow Potential Change in Absolute Response Gradient Tomography (ETESGFPCAGT)

The ETESGFPCAGT data is the representation of the correlation between the ESGFPT, ESCAGT and ET data sets. The ETESGFPCAGT data is used to determine the depth of formations that have high calculated groundwater flow potential, high inferred Zeta Potential and high electrical conductivity variability. This data thus indicates the probability of aquifers with fresh water saturation and high permeability. It is thus used to evaluate a site for fresh water aquifer systems.

The ETESGFPCAGT data is expressed as the normalised, relative, correlation index between the ESGFPT, ESCAGT and ET data sets with a maximum value of 100% and a minimum value of 0%.

Coordinate System

All point data collected for the or by the ATS survey system is in WGS84 Decimal Degree format. This is done as the Global Positioning system used to collect most electro-seismic survey position data is standardised to this format.

Once an Electro-Seismic project has been processed, the data is shown in industry standard Universal Transverse Mercator (UTM) conformal projection which uses a 2-dimensional Cartesian coordinate system to give locations on the surface of the Earth. All ATS models are projected to the UTM coordinate system to conform to internationally accepted practices.

The ATS point data CSV data file, provided with every project model, contains both the UTM and WGS84 Decimal Degree coordinate formats by default.

The elevation data used in all ATS models are displayed in meters above sea level (masl) or in feet above sea level (fasl), depending on client preference. Unless otherwise stated, in the report, all elevation data shown in the ATS project models are calculated from surface elevation reference data, provided by the client at each survey point.

As elevation data is collected, by the client, by GPS units that have elevation error tolerances, the elevation errors for the survey points may be unacceptably high. This can, unacceptably, affect the electro-seismic survey. In these cases, the ATS project supervisor may opt to use the NASA Shuttle Radar Topographic Mission (SRTM) elevation data instead. The STRM data set has a resolution of 90m and the specific ES sounding location elevation is an interpolated average of the elevation between known STRM elevations. This may still produce slight elevation variations, however, in some case the STRM elevation data is far superior to standard GPS survey readings.