Selective electrode usage for directional pulse power drilling

A system comprising:

• a pulse power drill string to be positioned in a borehole formed in a subsurface formation, the pulse power drill string to directionally drill the borehole at an angle that is offset from a longitudinal axis of the borehole and based on periodic pulses of an electrical discharge into the subsurface formation, the pulse power drill string comprising:
• an upper body having a longitudinal axis that is substantially the same as the longitudinal axis of the borehole, wherein the upper body comprises,
• an electrical source to generate an electrical energy;
• and
• a primary discharge capacitor to store the electrical energy;
• and
• an electrode assembly positioned below the upper body and at a bottom end of the pulse power drill string, the electrode assembly comprising,
• multiple electrodes, wherein at least a subset of the multiple electrodes is to periodically emit a pulse of the electrical discharge into the subsurface formation to drill the borehole, wherein an effective attribute of at least one electrode of the multiple electrodes is different than the effective attribute of other electrodes of the multiple electrodes, wherein the effective attribute comprises at least one of a shape and a size;
• a ground ring surrounding the multiple electrodes, wherein the ground ring is to receive the pulse of the electrical discharge after emission into the subsurface formation;
• and
• a controller configured to alter a direction of drilling of the borehole based on selection at least one emitting electrode of the multiple electrodes that is to emit the pulse of the electrical discharge and selection of at least one non-emitting electrode of the multiple electrodes that is to not emit the pulse of the electrical discharge.

A method comprising:

• performing a pulse power drilling operation, with a drill string positioned in a borehole formed in a subsurface formation, based on an electrical discharge periodically emitted into rock of the subsurface formation and from a subset of electrodes selected from among multiple electrodes of an electrode assembly, wherein an effective attribute of at least one electrode of the multiple electrodes is different than the effective attribute of other electrodes of the multiple electrodes, wherein the effective attribute comprises at least one of a shape and a size, wherein performing the pulse power drilling operation comprises,
• storing an electrical power as stored energy in a primary discharge capacitor of the drill string;
• in response to determining that a direction of the borehole is to be altered,
• selecting the subset of electrodes based on the direction of the borehole is to be altered;
• and
• in response to determining that at least one discharge criteria is satisfied,
• pulsing the electrical discharge from the subset of electrodes into the rock in the subsurface formation.