In those cases, the economics may favor injection of the produced water into a different permeable zone accessible to the borehole.
In other DOWS systems, a separate pump is needed to inject the water-rich stream into a permeable zone.
Trials have shown that a majority of properly operating DOWS systems may reduce the amount of water brought to the surface by around 75%.
[7] Hydrocyclone type DOWS systems usually use electric submersible pumps to overcome any pressure head differential needed to inject water into another zone.
Additionally, the supplemental draw of fluids into the wellbore by the pump has been known to increase the production of oil from some wells.
[7] A new line of research is being pursued in which permeable membranes are deployed in the wellbore to separate water from the oil and gas.