A subterranean oil or gas well apparatus is provided. The apparatus includes a single-bore production tubing hanger (4) arranged concentric with a wellhead (6). The tubing hanger includes a plurality of ports (17, 19) and channels arranged about the tubing hanger to give operators access to the production tubing annulus and provide chemical injection capability. The ports are closed by a sliding valve (16). The apparatus also includes annulus and production radial-bore stab assemblies (12) between a christmas tree (2) and an internal crossover assembly (10). The stab assemblies are extendable and retractable between the christmas tree and the crossover assembly to allow the retrieval and installation of each independently.
