Patent ID: 7784563
Filing Date: 2010-08-31
Classification: E21B

Abstract:
1. A drilling method for the drilling of boreholes in the ground, in which is circulated a suitable discharge fluid, comprising generating an electric discharge by high-voltage pulses between electrodes of opposite polarity, wherein the following elements have been incorporated: i electrodes moveable relative to each other and a drill-bit boss in a manner so that bottom-hole physical contact be secured for all the electrodes on all relevant bottom-hole topographies, ii nozzle jetting of the circulating discharge fluid (with point of jetting impact on the hole-bottom and jetting vector direction specific relative to the actual discharge gaps) so as to lift and remove the primary cuttings instantly as they come loose and with pressure expansion across the nozzles at no less than 4 MPa, iii down-hole deployment of a minimum of one high-voltage pulse generator a minimum fixed distance from the drill-bit and supplied from the surface at a 1 KV or other practical voltage level, iv borehole cross-sectional excavation coverage by a combination of rotational or oscillatory movement of the drill-bit boss and a plurality of electrodes situated on the bit face along one or a few radii and tangents, v ring-shaped hole-making with core storage, core transportation, down-hole closed loop discharge fluid circulation with prime mover energy supply, discharge fluid cleaning and cuttings' storage incorporated in it.