Patent ID: 8919236

Claim:
A method of detonating perforation charges in a well perforation gun comprising the steps of: combining a serially aligned assembly including a detonation cord, a firing head, a shaped charge pipe cutting sub having a tube cutting explosive enclosed within a housing and a perforating gun; connecting said cutting sub housing to said firing head and to said perforating gun to unitize said assembly; providing an aperture through said tube cutting explosive along an axis thereof; providing a plurality of shaped charge perforating explosives along a length of said perforating gun; threading said detonation cord from said firing head through said tube cutting explosive aperture; continuing said detonation cord from said tube cutting explosive aperture along the length of said perforating gun in sequential detonation proximity with said perforating explosives; positioning said assembly at a predetermined location within a well bore; activating said firing head to initiate a detonation wave along said detonation cord; detonating said tube cutting explosive by said detonation wave to sever said assembly by cutting said housing; and, detonating perforating charges within said perforation gun by said detonation wave after severance of said assembly.