METHOD OF LOGGING WELLS CASED WITH METAL COLUMN Russian patent published in 2013 - IPC G01V3/20 

FIELD: physics.

SUBSTANCE: probe in form of multiple measuring electrodes arranged in series and equidistant along the axis of the well and two current electrodes lying on different sides of said measuring electrodes is used. The measuring process consists of three cycles, where bipolar electric current pulses are alternately transmitted: 1) between first and second current electrodes (measurement conditions control mode); 2) relative electrode B to the first current electrode; 3) relative electrode B to the second current electrode. Each cycle involves measuring the transmitted currents and potential difference between each measuring electrode and electrodes lying away from it by one or two intervals between said electrodes. The second and third cycles also involve measuring potential of one of the measuring electrodes. Digital measuring results of the three cycles are used to determine resistivity at depths corresponding to positions of the measuring probes, except the outermost, using a corresponding formula which takes into account the diameter of the casing column.

EFFECT: high accuracy of determining resistivity.

1 dwg