12 that encompasses a fluid flow bore 14 the mandrel 12 is an integral element of a well work string the flow bore 14 is a fluid flow conduit usually having continuity with the well surface and may carry a pumped delivery of well working fluid the packer bladder 16 may be for example a reinforced rubber or polymer tube that extends substantially the full length of the mandrel at each tubular end the bladder is secured to the mandrel 12 by collars having a lipped overlay 19 between the collars an uninflated bladder tightly overlies the mandrel 12 for running into and placement within the well when expanded by fluid pressure the overlaid bladder tube 16 expands from the mandrel surface to form an inflation chamber 30 one of the collars the valve collar 18 is tooled for an inflation conduit 22 a fluid flow aperture 20 through the mandrel 12 wall is aligned with the collar inflation conduit 22 between the flow aperture 20 and the packer inflation chamber 30 the inflation conduit 22 includes several fluid flow control elements comprising a fluid flow check valve 24 and a flow labyrinth 26 in some cases fluid flow through the inflation conduit 22 may also be restricted by pressure responsive opening and closing valves.