Shaped charge retainer system

摘要

An apparatus and method for retaining shaped charges. A foam core having charge carrying recesses can be constructed from a single piece or from multiple sections. Shaped charges are insertable within the foam core recesses so that the shaped charges are proximate to a detonator cord positioned inside or outside of the foam core. The foam core assembly holding the detonator cord and shaped charges is inserted into a housing such as a cylindrical tubing to construct the perforating gun. A seal isolates the shaped charges from pressurized well fluids. The housing can be attached to a firing head and lowered to the desired depth in a well casing. Additional foam sections can be added to modify the number and orientation of the shaped charges. The invention is particulaly useful with thin housing material and substantially reduces the manufacturing cost of perforating guns.