METHD FOR PERFORATING A WELLBORE IN LOW UNDERBALANCE SYSTEMS
By substantially eliminating the crushed zone surrounding a perforation tunnel and expelling debris created upon activation of a shaped charge with, first and second successive explosive events, the need for surge flow associated with underbalanced perforating techniques is eliminated. The break down of the rock fabric at the tunnel tip, caused by the near- instantaneous overpressure generated within the tunnel, further creates substantially debris-free tunnels in conditions of limited or no underbalance as well as in conditions of overbalance.