To highlight the contact between Oxfordian conductive marls (in green) and resistive Eocene sands (in red) two acquisition geometries have been implemented: one with a horizontal dipole and another with a vertical dipole.

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  Step 1: Map of resistivities. Acquisition has been conducted with an EM 34-3 horizontal dipole. The coil spacing was 20m.


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  Step 2: Map of resistivities. Acquisition has been conducted with an EM 34-3 vertical dipole. The coil spacing was 20 m.
  The ability of the horizontal dipole geometry to detect lateral variations of resistivities, conjugated to the ability of the vertical dipole geometry to investigate deeper in the subsurface enabled to exhibit a compartment of Cenomanian age limited by two series of faults between the two geological units.

The following example is derived from a research study on the origin of preserved collapses in a tertiary sedimentary basin.
The measurements were carried out with different configurations using either a vertical or a horizontal dipole and 3 source-receiver spacings (10, 20 and 40 meters), leading to 6 depths of investigation. The interpretation combined with the realization of electric tomography and reconnaissance surveys made the geology of the basin reconstruction possible.

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  Step 3: Map of resistivities. Acquisition has been conducted with an EM 34-3 horizontal dipole. The coil spacing was 10 m.


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  Step 4: Map of resistivities. Acquisition has been conducted with an EM 34-3 vertical dipole. The coil spacing was 40 m.


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  Step 5: Southwest - Northeast geological section driven by the resistivity maps.


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  Step 6: Geological map showing the lithological units and the structural limits of the basin.