Abstract: An apparatus for downhole separation of an oil/water fluid and the injection of the separated water into the formation includes a casing in a borehole, a tubing string in the casing, first perforations in the casing at a production zone in the borehole for admitting the mixture into an annulus between the casing and the tubing string, second perforations in the tubing string for admitting production fluid from the casing into the tubing string, third perforations in the casing for discharging separated water from the annulus into the formation, a packer in the annulus separating the first perforations from the third perforations, a first check valve in the tubing string above the packer for admitting the mixture from the tubing string into the annulus where water separates by gravity from the hydrocarbons for discharge through the third perforations, and a second check valve in the tubing string above the first check valve for admitting separated hydrocarbons from the annulus into the tubing string for passag

Abstract: The invention provides a method and apparatus for the downhole separation of a gas/oil/water fluid mixture and the injection of the separated water component into the formation containing the borehole. The fluid mixture is delivered into the wellbore through perforations in a casing at a production zone and delivered through check valves in a tubing string into an annulus between the casing and the tubing string. Hydrocarbons are returned to the production tubing and flow to the surface under formation or pump pressure and water is discharged from the annulus into an injection level isolated from the production zone.