A new gun deployment system based on, production packer technology was used to complete two oil fields in the North Sea. The polished bore receptacle (PBR) and, hydraulic-set permanent packer, were designed with the guns hung off the seal assembly of the PBR the system allowed the tubing-conveyed Perforating (TCP) guns to be recovered it they mal- functioned. The completion and. TCP guns were run, and the wells were completed and perforated underbalanced in a single trip.