ELECTROPULSE DRILLING HEAD Russian patent published in 2006 - IPC E21B7/00 

FIELD: well drilling, particularly means adapted to drill wells, form slits, cut rock and break frangible dielectric material.

SUBSTANCE: drilling head comprises spring-loaded high-voltage electrode system including electrodes and earthed electrode system having electrodes, which are separated one from another by dielectric with flushing windows. High-voltage system has additional flushing channel provided with seat adapted to arrange temporary ball hydroseal. The ball hydroseal is formed of elastic or dissolving or melting material. One or several electrode channels are formed over the seat. Each electrode channel is adapted to receive spring-loaded additional electrode.

EFFECT: increased drilling efficiency due to possibility to change inter-electrode distance without tripping operations execution.

3 cl, 2 dwg