US Patent 9840898 System and methods for controlled fracturing in formations

Controlled fracturing in geologic formations is carried out by a system for generating fractures. The system comprises: a plurality of electrodes for placing in boreholes in a formation with one electrode per borehole, for the plurality of electrodes to define a fracture pattern for the geologic formation; a first electrical system for delivering a sufficient amount of energy to the electrodes to generate a conductive channel between the pair of electrodes with the conductivity in the channel has a ratio of final to initial channel conductivity of 10:1 to 50,000:1, wherein the sufficient amount of energy is selected from electromagnetic conduction, radiant energy and combinations thereof; and a second electrical system for generating electrical impulses with a voltage output ranging from 100-2000 kV, with the pulses having a rise time ranging from 0.05-500 microseconds and a half-value time of 50-5000 microseconds.