Apparatus and method for use in subsurface oil and gas well perforating device

A detonation shock wave perforating system for use in perforating subsurface earth formations traversed by a borehole. The system includes a plurality of mechanically serially connected perforating gun sections, each section of which may contain a plurality of shaped charges mounted therein and a length of detonator cord. To provide coupling of the detonation shock wave between housing sections, a booster is coupled to the detonator cord and mounted proximate a shaped charge having its axis of perforation aligned along the longitudinal axis of the gun. Detonation of the shaped charge results in a jet which detonates a quantity of explosive material in the subsequent gun section the detonation of which transfers a detonation shock wave into a detonator cord, thereby detonating any explosive connected thereto. An alternate embodiment provides for coupling of the detonator wave without using a shaped charge unit. Further, the propagation system allows any excess length of detonator cord present within the perforating gun sections to be removed.