Modular gun systems for use in the perforating of casing during oil and gas well completions, the systems comprising detonators and explosive shaped charges; Oil field equipment carrier assemblies comprised of explosive charges and detonators contained within pre-wired tubular subs in the nature of pipes, and also comprised of addressable switch systems containing electric circuitry that receive and transmit detonation signals, all of the aforementioned for use in completing oil and gas wells; Perforating explosive equipment for use in recompletion perforating applications in unconventional oil and gas wells, namely, perforating guns specially adapted for use with explosive charges