This reports, DOWS technology reduced the quality of produced water that is handled at the surface by separating it from the oil downhole and simultaneously injecting it underground. The two primary components of a DOWS system are an oil/water separation system and at least one pump to lift oil to the surface and inject the water. Two basic types of DOWS have been developed -- one type using hydrocyclones to mechanically separate oil and water and one relying on gravity separation that takes place in the well bore.