Pulsed electric rock drilling apparatus with non-rotating bit
The present invention provides for pulsed powered drilling apparatuses and methods. A drilling apparatus is provided comprising a bit having one or more sets of electrodes through which a pulsed voltage is passed through a mineral substrate to create a crushing or drilling action. The electrocrushing drilling process may have, but does not require, rotation of the bit. The electrocrushing drilling process is capable of excavating the hole out beyond the edges of the bit with or without the need of mechanical teeth.
1. A pulsed power drilling apparatus for passing a pulsed electrical current through a substrate to break the substrate, the apparatus comprising:
an electrocrushing drill comprising a non-rotatable drill bit;
a pulsed power generator linking to said non-rotatable drill bit for delivering high voltage pulses; and
at least one set of at least two electrodes disposed on said non-rotatable drill bit, said at least one electrode set providing directional control.
2. The apparatus of claim 1 comprising a plurality of electrode sets disposed on said non-rotatable drill bit, wherein a pulse repetition rate or pulse energy produced by said pulsed power generator variably provided to said plurality of electrode sets causes one side of said non-rotatable drill bit to break more substrate, and causing said non-rotatable drill bit to change direction so that said non-rotatable drill bit is steered through the substrate.
3. The apparatus of claim 1 further comprising a bottom hole assembly comprising at least one electrohydraulic projector.
4. A method for breaking and drilling a substrate comprising:
providing an electrocrushing drill comprising a non-rotating drill bit;
disposing at least one set of two electrodes on the non-rotating drill bit, defining therebetween at least one electrode gap;
delivering a pulsed power current between at least one set of two electrodes and through the substrate, breaking the substrate; and
delivering another pulsed power current between another set of two electrodes and through the substrate for directionally controlling the non-rotating drill bit.
5. The method of claim 4 further comprising drilling a larger hole out beyond edges of the hole without using mechanical teeth.
6. The method of claim 4 further comprising disposing the electrode sets downhole in a bottom hole assembly.
7. The method of claim 4 further comprising locating the pulsed power system at a surface with a pulse sent over a plurality of cables.
8. The method of claim 4 further comprising locating the pulsed power system in an intermediate section of a drill string.