Positive alignment insert (pai) with imbedded explosive

Abstract

Redundant explosive transfer between two explosive carrier devices is accomplished by inserting into a transfer sub or gun head a non-moveable explosive means for receiving the detonating cord which, at its first end, establishes a gap from an adjacent positive alignment insert (PAI) and wherein the length of explosive means is sufficient to assure detonation between the explosive means and the detonating cord in the event that the detonating cord shrinks due to the temperature of well applications. In the preferred embodiment of the present invention, a positive alignment insert consists of an aluminum insert housing having an annular region of imbedded explosive. The annular region of the explosive-filled insert is typically annularly lined with an aluminum sleeve for protecting the explosive within and maintaining an annular region of sufficient diameter to allow for the passage and placement of the detonating cord and booster. A positive alignment insert is inserted into both the crossover pin-and-box and the grooved tandem, or into similar transfer subs, or into gun head adapters. A stop is provided in the crossover sub, which maintains the minimum gap required to transfer a high order detonation from the explosive in the first positive alignment insert to the explosive in the second positive alignment insert. Thus, when positive alignment inserts are used within a transfer sub, the original gap between bi-directional boosters is not as critical because detonation will propagate from one detonating cord to the next by propagating through the explosive within the first positive alignment insert to the explosive in the second positive alignment insert.