Downhole separation of produced water in hydrocarbon wells, and simultaneous downhole injection of separated water and surface water

摘要

A method and system for the downhole separation and injection of surface water and water contained in a produced mixture from an underground formation of a hydrocarbon well containing hydrocarbon and water. Downhole separation of the produced mixture into a predominately water component and predominately hydrocarbon component is achieved using an oil-water separator. Surface water is delivered to a downhole fluid-driven pump under pressure so as to drive the pump. The downhole-separated predominately water component of the produced mixture is directed to the pump, by way of the pump and combined with surface water to obtain a combined fluid. The combined fluid is directed to a downhole injection formation by way of the pump. Oil is transported to the head of the well either naturally under the eruptive force of the well, or with the assistance of regular artificial lift methods, including gas-lift. This invention allows for injection of surface water and downhole-separated water in the same wellbore while producing oil to surface.