Abstract: A combination perforating/gravel pack assembly includes a crossover circulation tool, a gravel pack screen, gravel pack accessories and a perforating gun which are interconnected by tubular flow conductors. External seals are located at longitudinally spaced locations along the upper end of the flow conductor string, above the gravel pack accessories and screens. External seals are also located at longitudinally spaced locations along the lower end of the flow conductor string, intermediate the screen and the perforating gun assembly. After crossover and reverse circulation are established, gravel slurry is pumped through an inner service string into the production annulus between the screen and the perforated casing. The slurry liquid is returned through a tell-tale screen upwardly through the washpipe and circulation tool, where it crosses over for return flow to the surface through a bypass annulus between the inner service string and the upper flow conductor seal assembly.