Abstract: A method for downhole separation of oil and water within a production fluid downhole in an oil well, includes providing a cyclone separator connected to the outlet of a downhole pump or two or more cyclone separators mounted within a housing and connected to the outlet of a downhole pump. One outlet of the separator or housing is connected to a conduit for transporting the lower density stream to the surface and the second outlet of the separator or housing is connected to a conduit for transporting the higher density stream to an underground formation. The pre-separator downhole pump is preferably selected to maintain dissolved gases in solution while production fluids are within the pump and separators and prevent gas breakout from occurring.

Abstract: A method of downhole cyclone oil/water separation is described. Firstly, place a cyclone separator downhole in an oil well producing a mixed stream of oil, water and gas. The cyclone separator includes a separation chamber wherein liquids of differing densities are separated, at least one mixed liquids inlet through which liquids pass into the separation chamber, a first outlet for liquids of a first density range to pass from the separation chamber and a second outlet for liquids of a second density range to pass from the separation chamber. Secondly, connect the first outlet to a recovery conduit extending to surface. Thirdly, connect the second outlet to a disposal conduit extending to a selected disposal site. Fourthly, connect the mixed liquids inlet to pumping means and pump a mixed stream of oil, water and gas into the separation chamber of the cyclone separator.

Abstract: A method for reducing the amount of formation water in oil recovered from an oil well. Firstly, place a cyclone separator downhole in a producing oil well. The cyclone separator includes a separation chamber wherein liquids of differing densities are separated, a mixed liquids inlet through which liquids pass into the separation chamber, a first outlet for liquids of a first density to pass from the separation chamber, and a second outlet for liquids of a second density to pass from the separation chamber. Secondly, connect the first outlet to a recovery conduit extending to surface whereby a stream of mainly oil is separated in the separation chamber from the oil/water stream flowing through the mixed liquids inlet. The stream of mainly oil flowing out the first outlet and along the recovery conduit to surface.