MAGNETIC LOCATION WITH THE USE OF PLURALITY OF WELL ELECTRODES Russian patent published in 2018 - IPC E21B47/228 E21B47/92 

FIELD: drilling of soil or rock.

SUBSTANCE: invention relates to the proximal wells drilling and can be used to determine the distance between wells. Disclosed is the magnetic ranging system, containing: wellbore in the formation; conductive casing string in the said wellbore; and excitation electrode and return electrode in the said wellbore, electrically connected to the conductive casing string. Wherein the excitation electrode is located in the well below the return electrode. Excitation electrode and the return electrode generate current in the casing string, which results in the electromagnetic signal, propagating through the said formation to the sensor in the other well.

EFFECT: technical result is a wider range of equipment.

20 cl, 12 dwg