| 摘要 |
<p>A firing head assembly for a well bore perforating gun in which assembly alternative firing paths are provided. A first detonation cord (26) passes longitudinally through a generally cylindrical housing (11), providing a firing path from a firing head above the housing to a perforating gun below the housing. A firing pin (23) and second detonation cord (27) are located in the housing and are positioned radially offset from the longitudinal axis of the housing. Boosters (64,65) on the first and second detonation cords are positioned adjacent one another and opposite a third booster. Either or both of the first and second boosters may be used to fire the third booster. No splicing of detonation cords is required and the detonation cords are completely within a protective housing. The firing pin may be actuated by pressure or mechanical means.</p> |
