Electro-hydraulic control of variable choke valves in a multi-zone well

摘要

A well system and method of controlling flow at a number of locations along a wellbore, comprises a number of flow control or choke valves 52. The valves are coupled by an electric control line 54 and a singe hydraulic supply line 56. The position of each choke valve can be individually controlled through the inputs of the said electric and single hydraulic line. An electro-hydraulic servo valve 60 is preferably used to selectively divert the hydraulic input to a dual-line actuator 66. This may be achieved by alternating between a straight-flow position 70 and a cross-flow position 72. The dual-line actuator may be combined with an indexing sleeve 64 to sequentially move the variable choke between open, closed and intermediate positions. The well system is of particular application to multi-zone completions and has the advantage that it does not require multiple hydraulic lines.