Apparatus, assembly and process for allowing gas lift operations to be conducted along a relatively long perforated interval below a packer in a subterranean well. An elongated segregation member is lowered into locking engagement with a bypass mandrel secured to a tubing string above the packer. This segregation member is configured and dimensioned to define two fluid flow paths. Fluid produced into the well from the subterranean region is conveyed to the surface via the second flow path and can be assisted by gas injected into the first flow path via retrievable gas lift valves in the tubing string above and below the packer. Pressurized gas is conveyed via the first flow path to these retrievable gas lift valves.