A method and apparatus for simultaneously producing fluid from one or more zones of an oil or gas well, while injecting fluid into one or more other zones of the well, and for converting a depleted production zone into an injection zone, by remotely shifting sleeves in the apparatus to selectively align...http://www.google.co.uk/patents/USRE40308?utm_source=gb-gplus-sharePatent USRE40308 - Multi-purpose injection and production well system
