Cooling of electrocrushing drill assembly

An electrocrushing drilling apparatus comprising:

• one or more components comprising a power supply, a control and communications unit, a liquid coolant pump, a drilling fluid pump, a boost charger, a power pulse generator, or any combination thereof, located at an earth surface of a wellbore of a hydrocarbon well;
• a bottomhole assembly positionable in the wellbore and comprising:
• an electrocrushing drill assembly including an electrocrushing drill bit, the electrocrushing drill assembly positionable to advance the wellbore by fracturing rock within the wellbore via high voltage electrical energy pulses emitted from a plurality of electrodes of the electrocrushing drill bit;
• and
• a plurality of fluid pathways passing through the electrocrushing drill assembly, at least one of the plurality of fluid pathways positionable in fluid communication with a liquid coolant conduit that is located within the drill string to convey liquid coolant from the liquid coolant pump to the electrocrushing drill assembly, and at least one of the plurality of fluid pathways positionable in fluid communication with a drilling fluid conduit that is located within the drill string to convey drilling fluid from the drilling fluid pump to the electrocrushing drill assembly.

A method comprising:

• coupling a bottomhole assembly to a downhole end of drill string, the bottomhole assembly including at least one electronic component of a downhole portion of an electrocrushing drill assembly, the at least one electronic component comprising an input filter, a boost charger, a pulsed power controller, a pulse transformer, a switch bank, a primary capacitor, a secondary capacitor, a downhole coolant pump, a plurality of electrodes, or any combination thereof;
• deploying the drill string with the bottomhole assembly coupled thereto into a wellbore of a hydrocarbon well;
• and
• using (i) a liquid coolant pump located at an earth surface of the hydrocarbon well to convey liquid coolant from a liquid coolant source downhole to the at least one electronic component of the electrocrushing drill assembly via a liquid coolant conduit located within the drill string, and (ii) a downhole coolant pump that boosts a pressure and a flow rate of the liquid coolant conveyed downhole by the liquid coolant pump located at the earth surface before directing the liquid coolant to the at least one electronic component of the electrocrushing drill assembly.