ELECTRICAL LOGGING APPARATUS Russian patent published in 2014 - IPC G01V3/24 

FIELD: physics.

SUBSTANCE: apparatus consists of a probing device with spherical electric field focusing. The probing device has a central forward current electrode, a remote counter current electrode, a pair of counter focusing electrodes, a pair of measuring electrodes at the centre of the probing device and two pairs of control electrodes, lying over and under the counter current electrodes, respectively. The electronic unit of the probing device has an alternating current source, one output of which is connected to the central current electrode, and the other output is connected through a switch to the counter current electrode and the pair of counter current electrodes; measuring channels capable of measuring principal and focusing currents and potential differences between control electrodes and between internal measuring and external control electrodes. The probing device further includes a pair of measuring electrodes, arranged symmetrically about the central electrode in the external zone of the probing device, over and below the control electrodes, respectively. The electronic unit of the apparatus includes an additional channel for measuring potential difference between an additional pair of measuring electrodes and an external pair of control electrodes.

EFFECT: high accuracy of determining resistivity of rocks and determining permeable formations in a well column.

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