Patent ID: 7905285

Claim:
A method for creating a period of dynamic underbalance at a zone of interest in a wellbore comprising: positioning a perforation assembly in the wellbore at the zone of interest for creating an annulus between the assembly and the wellbore, the annulus containing fluid and having an initial hydrostatic pressure, the assembly having at least a propellant-type perforation gun and one or more surge canisters, the initial hydrostatic pressure encouraging maximal burn of propellant of the propellant-type perforation gun; actuating the propellant-type perforating gun for igniting the propellant, creating an initial pressure event and forming perforations at the zone of interest and wherein dynamic pressure in the annulus at the zone of interest reaches a first initial elevated pressure; delaying until the dynamic pressure diminishes from the first initial elevated pressure; wherein the initial pressure event creates an interface reflection pressure wave traveling along the wellbore and wherein the delaying further comprises delaying until about the time the interface reflection pressure wave reaches the zone of interest: and then opening at least one of the one or more surge canisters so as to receive a surge of the fluid therein for creating the period of dynamic underbalance.