Abstract: The present invention provides methods and apparatus for separating fluids using one or more hydrocyclone separators and a mixer disposed upstream from the hydrocyclone separators. The mixers are preferably static or rotary type mixers which mix the fluids prior to their delivery into the hydrocyclone separator. Using mixers provides a more homogeneous mixture of oil and water to the hydrocyclone separators in order to increase the efficiency of the separation. By controlling the degree of mixing it is also possible to substantially avoid the formation of emulsions.

Abstract: Methods and apparatus are provided for separation of liquids of different densities in production fluid streams from underground wells. Methods and apparatus are also provided for separation of gas, oil and water in production fluids, transportation of the separated fluids to the surface, as well as reinjection of separated water from the production fluids into other formations. Other aspects include new separation arrangements which include gas or liquid driven motors, designs for multi-stage hydrocyclone separators and use of beam or rod pumps.

Abstract: The present invention provides an apparatus and method of producing a stream of hydrocarbons and water from a wellbore and separating the stream into a hydrocarbon-rich stream and a water-rich stream that can be reinjected into the wellbore from which it was produced. The method involves producing a production stream from production tubing in the wellbore to a separator located at least partially above the wellbore, separating the production stream into a water-rich stream and an oil-rich stream, reinjecting the water-rich stream into the wellbore from which it was produced; and maintaining separation of the water-rich stream from the production stream.