Patent ID: 6581700
Filing Date: 2003-06-24
Classification: E21B

Abstract:
A method of drilling a subterranean formation using a drilling rig, a drill string, a fluid pump located substantially at the drilling rig, a drilling fluid and plurality of solid material impactors, the drill string including a feed end located substantially near the drilling rig and a nozzle end including a nozzle supported thereon, the method comprising:providing at least one nozzle such that a velocity of the drilling fluid while exiting the nozzle is substantially greater than a velocity of the drilling fluid while passing through a nominal diameter flow path in the nozzle end of the drill string; introducing the plurality of solid material impactors into the drilling fluid to circulate the plurality of solid material impactors with the drilling fluid into the feed end of the drill string, through the drill string and through the nozzle, the drilling fluid being pumped at at least one of a selected circulation rate and a selected pump pressure; pumping the drilling fluid at a pressure level and a flow rate level sufficient to satisfy an impactor mass-velocity relationship wherein a substantial portion by weight of the plurality of solid material impactors creates a structurally altered zone in the formation having a structurally altered zone height in a direction perpendicular to a plane of impaction at least two times a mean particle diameter of particles in the formation impacted by the plurality of solid material impactors; circulating at least some of the drilling fluid, the plurality of solid material impactors and the formation cuttings away from the at least one nozzle.