Patent ID: 7635027

Claim:
A method of completing a well, comprising: (a) providing a firing head assembly comprising a sealed chamber containing a piston for movement along a firing head axis, a firing pin axially aligned with the piston, and an impact detonator axially aligned with the firing pin; (b) installing the firing head assembly within a sub and linking the impact detonator to a perforating charge; (c) securing the sub to a string of conduit and lowering the conduit into a wellbore; (d) lowering a drill bit into the conduit, pumping drilling fluid through the drill bit into the conduit and rotating the drill bit against the firing head assembly to disintegrate at least a portion of the sealed chamber, thereby exposing the sealed chamber to the fluid pressure of the drilling fluid in the conduit; and (e) in response to the fluid pressure, the piston driving the firing pin against the detonator, causing the perforating charge to detonate to create a perforation through the conduit and into an earth formation.