| 摘要 |
<p>A logging method for measuring the resistivity of formations having a borehole passing therethrough, wherein a logging sonde is suspended inside the borehole by means of a cable, the sonde comprising electrodes for injecting alternating currents into the formations, these electrodes comprising a central electrode A0 and focusing electrodes, together with a return electrode B and a potential reference electrode N, one of which is placed above the sonde and the other of which is placed at the surface, and producing a resistivity log from the current I0 emitted by the central electrode and the potential difference between the sonde and the reference electrode. The method further comprises the step of producing a second log of the resistivity with the return and potential reference electrodes being placed as for the first log and under conditions such that the investigation depth is different from that applicable to the first log. The invention is applicable to correcting the Groningen effect. <IMAGE></p> |
