Patent ID: 8191619
Filing Date: 2012-06-05
Classification: E21B

Abstract:
1. A downhole system for extracting fluids, comprising a casing pipe and a tubing extending through said casing pipe, between which pipe and tubing are formed separate isolated cavities, each cavity communicating, via perforations, with a respective producing formation; in each one of the isolated cavities, a hydraulic machine is coupled to the tubing to achieve a common flow, the hydraulic machine comprising a hydraulic motor and pump; the hydraulic machines being in different isolated cavities and being adapted to be adjusted independently of one another to achieve a flow of each extracted fluid at a respective flow rate from each corresponding isolated cavity into a common flow in the tubing; wherein when an isolated cavity has a natural positive pressure to drive a flow of the extracted fluid through the pump of the hydraulic machine, the pump acts as a motor to drive the hydraulic motor as a passive pump, and the respective flow rate of the isolated cavity is achieved by constricting a flow of a working hydraulic fluid being pumped by the passive pump; and wherein when an isolated cavity has a natural negative pressure, the hydraulic motor adjustably drives the pump to provide artificial lift of the corresponding extracted fluid.