| 摘要 |
According to the invention, the device is of the type using a probe 102 comprising a plurality of emission electrodes 106 arranged in a ring at the centre of the probe 102 on a cylindrical mandrel 108, at least two focusing electrodes, each located at one end of the probe 102, a collection electrode 115, generator means 117 for passing respective currents between each of the emission electrodes 106 and the collection electrode 115, means for measuring the variations in the current emitted by the emission electrodes as a function of the depth of the probe in the borehole. This detection device is characterised in that it comprises correction means capable of acting on the potential of the emission electrodes 106, in order to compensate for the diffusion of the electric current in the electrically conducting fluid medium 104 filling the borehole. <IMAGE>
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