Gas monitoring systems, SurfMog®, ShallowMoG®, SysMoG®, GH2ASBUSTERS®

Solexperts manufactures monitoring systems for soil gas and dissolved gases as well as in-situ gas sampling systems for boreholes up to 1500 metres deep. The product family sets new standards in terms of detectability and allocation of dissolved gases to the source formation and thus opens up new possibilities in the prospection of hydrogen, helium and natural gas as well as the monitoring of geological CO2 deposits or underground hydrogen storage facilities.

The diagram opposite shows possible applications of the various systems for measuring dissolved gases in groundwater down to a depth of 1500 metres. The probes are the result of many years of very successful collaboration with the GeoRessources laboratory at the University of Lorraine and the CNRS.




Application overview of Solexperts gas monitoring and sampling systems using the example of Follschviller Lorraine

SurfMoG®: unsaturated zone, soil gas up to 1 m depth

is an IoT tool for gas monitoring in the unsaturated zone down to a depth of approximately 1 metre with the following features:

  • Easy to use: stand-alone logger with battery and data transmission, IOT visualisation
    Gas specific sensors for:
    • Hydrogen: SurfMoG-H2 in cooperation with the company 45-8 Energy
    • Methane: SurfMoG-CH4
    • CO2: SurfMoG-CO2
    • Helium: SurfMoG-He
    • in combination with temperature and optional humidity


Specifications of the specific gas sensors
Procedure for installing a SurfMoG® probe
SurfMoG® probes before installation
Wireless data transmission

ShallowMoG®: unsaturated and saturated zone, down to approx. 50 m depth

is an IoT tool for gas monitoring in the unsaturated and saturated zone down to a depth of approximately 50 metres and has the following features:

  • Stand-alone logger at the surface with battery, data transmission and IOT visualisation
  • Probe diameter: 76 mm
  • Gas specific sensors for:
    • Hydrogen: ShallowMoG-H2
    • Methane: ShallowMoG-CH4
    • CO2: ShallowMoG-CO2
    • Helium: ShallowMoG-He
    • in combination with temperature


Specifications of the specific gas sensors
Schematic representation of the borehole probe with the gas sensor and the data logger on the surface
ShallowMoG® probe before installation
Function test: Concentration curve in test well after two short hydrogen injections
ShallowMoG® borehole probe

SysMoG®: Detection of dissolved gases in boreholes up to 1500 m, 3000 m in development

SysMoG® is a system for detecting dissolved gases in aquifers in boreholes up to a depth of 1500 metres. The probe is available in two configurations, depending on the application:

Continuous measurement:

The measuring system consists of a borehole probe with a chamber into which the dissolved gases from the surrounding groundwater diffuse. The probe is connected to the measuring module on the surface via two pipes and a circulation module. Various analysers, such as Raman or FTIR spectrometers, are used to detect the gases. The measuring module integrated into the circuit continuously detects the components of the gas mixture and records the concentration development of the individual gases over time. The borehole probe can be installed in an open borehole, e.g. with a logging winch. Alternatively, it can also be integrated into a measuring interval of a multi-packer system. The adjacent figure schematically shows the SysMoG® system for continuous measurements.

Schematic representation of the SysMoG® measuring system for continuous measurements with its three modules, borehole probe, circulation module and measuring module.
Flight photo of the Follschviller test site
Philippe de Donato explains the surprising results of the gas analysis
Surface test equipment

Sampling of dissolved gases with SysMoG®GH2ASBUSTERS:

With SysMoG®GH2ASBUSTERS, depth-specific gas sampling is carried out with a SysMoG® probe and a winch (to a depth of 1500 m, 3000 m is under development).  The system consists of a borehole probe with a chamber into which the gases (dissolved in the groundwater) diffuse. When the gas pressure in the probe has stabilised, the gas concentrations inside and outside the probe chamber are in equilibrium. A valve in the probe is then opened and two 75 ml ampoules are filled. After closing the valve, the probe is removed and the gas samples are analysed either on-site or in a laboratory.

Schematic representation of the borehole probe with the two sample vials
Increase in hydrogen concentration with depth, example Lorraine
Typical pressure curve in the borehole probe, pressure stabilization takes more than 10 hours.
Tripod is sufficient, no drill rig necessary
Sampling in Follschviller, Lorraine
Field engineer operating the winch



Contact persons

Médéric Piedevache

Engineering Geologist ENSG

Member of the extended executive board
Branch manager Nancy, France

T +33 (0) 3 83 94 04 50

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Yanick Lettry

Geologe / Hydrogeologist CHYN

Hydrogeological instrumentation and tests /
QM hydrogeological Instrumentation / Geochemistry

T +41 (0) 44 806 29 53

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Thomas Fierz

Civil Engineer ETHZ

Managing director Solexperts AG and branches /
Manager Solexperts France SARL /
Manager Solexperts GmbH

T +41 (0) 44 806 29 29

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