Flow control device

Abstract

A flow control device and associated method are provided, the flow control device comprising: a body locatable within a wall of a tubular and defining a primary inlet and a primary outlet, wherein a primary flow path is defined between the primary inlet and primary outlet; a valve member is disposed within the body, the valve member being moveable in reverse first and second directions to selectively vary a flow area of the primary flow path; and, a sealed pilot pressure chamber defining a pilot pressure inlet for receiving a pilot pressure, the valve member being in pressure communication with the sealed pilot pressure chamber such that pilot pressure may act to bias the valve member in one of the first and second directions, wherein the pilot pressure is provided as a function of a property of fluid flowing through the primary flow path.

1 . A flow control device, comprising;
 a body locatable within a wall of a tubular and defining a primary inlet and a primary outlet, wherein a primary flow path is defined between the primary inlet and primary outlet;   a valve member disposed within the body, the valve member being moveable in reverse first and second directions to selectively vary a flow area of the primary flow path; and   a sealed pilot pressure chamber defining a pilot pressure inlet for receiving a pilot pressure, the valve member being in pressure communication with the sealed pilot pressure chamber such that pilot pressure may act to bias the valve member in one of the first and second directions, wherein the pilot pressure is provided as a function of a property of fluid flowing through the primary flow path.   
     
     
         2 . The flow control device according to  claim 1 , wherein the flow rate through the flow control device is varied based upon one or more properties of a fluid flowing along the primary flow path. 
     
     
         3 . The flow control device according to  claim 1 , wherein the position of the valve member and the size of the flow area provided is determined by a pressure differential between at least the inlet of the primary flow path and within the sealed pilot pressure chamber. 
     
     
         4 . The flow control device according to  claim 1 , comprising a pilot pressure system, wherein the pilot pressure is provided from the pilot pressure system. 
     
     
         5 . (canceled) 
     
     
         6 . The flow control device according to  claim 4 , wherein the pilot pressure system comprises a secondary flow path. 
     
     
         7 . The flow control device according to  claim 6 , wherein the secondary flow path comprises an inlet and an outlet. 
     
     
         8 . The flow control device according to  claim 6 , wherein the secondary flow path is in pressure communication with the sealed pilot pressure chamber. 
     
     
         9 . The flow control device according to  claim 6 , wherein the secondary flow path is partially formed through the body of the flow control device. 
     
     
         10 . The flow control device according to  claim 6 , wherein the secondary flow path is partially formed through the wall of a tubular within which the flow control device is located. 
     
     
         11 . The flow control device according to  claim 6 , wherein the secondary flow path is configured to create a pressure drop between the inlet and the outlet. 
     
     
         12 . The flow control device according to  claim 6 , wherein pressure is communicated to the sealed pilot pressure chamber from a point between the inlet and the outlet of the secondary flow path. 
     
     
         13 . The flow control device according to  claim 12 , wherein the secondary flow path provides a static pressure within the sealed pilot pressure chamber. 
     
     
         14 . The flow control device according to  claim 13 , wherein the static pressure within the sealed pilot pressure chamber is determined by the inlet pressure of the secondary flow path and the pressure drop along the secondary flow path. 
     
     
         15 . The flow control device according to  claim 6 , wherein the inlet pressure of the primary flow path and the secondary flow path are substantially the same. 
     
     
         16 . The flow control device according to  claim 6 , wherein a fluid source provides fluid to both the primary and secondary flow paths, wherein the fluid source is the same for both the primary and secondary flow paths. 
     
     
         17 . The flow control device according to  claim 6 , wherein the secondary flow path comprises one or more flow restrictions. 
     
     
         18 . The flow control device according to  claim 1 , wherein biasing the valve member in the first direction moves the valve member towards a fully open position, increasing the flow area. 
     
     
         19 . The flow control device according to  claim 18 , wherein the valve member is biased in the first direction by fluid pressure at the primary inlet. 
     
     
         20 . The flow control device according to  claim 1 , wherein biasing the valve member in the second direction moves the valve member towards a fully closed position, decreasing the flow area. 
     
     
         21 . The flow control device according to  claim 20 , wherein the valve member is biased in the second direction by fluid pressure within the sealed pilot pressure chamber. 
     
     
         22 . The flow control device according to  claim 1 , wherein the pilot pressure is provided as a function of at least one of the viscosity and the density of the fluid flowing through the primary flow path. 
     
     
         23 . The flow control device according to  claim 1 , comprising a sealing arrangement disposed between the valve member and the body of the flow control device, wherein the sealing arrangement provides a biasing force biasing the valve member in one of the first or second directions. 
     
     
         24 . A downhole flow control method, the method comprising:
 flowing a fluid through a primary flow path of a flow control device disposed within the wall of a tubular, wherein the flow control device comprises a valve member disposed within the primary flow path;   flowing a fluid through a secondary flow path, wherein the secondary flow path is configured to provide a pressure variation of the fluid flowing through the secondary flow path based upon a variation of at least one characteristic of said flowing fluid; and   communicating a pressure from the secondary flow path to a sealed pilot pressure chamber, said pressure providing a biasing force on the valve member to vary the flow area of the primary flow path.   
     
     
         25 . The method according to  claim 24 , wherein the at least one characteristic of the flowing fluid that provides the pressure variation within the secondary flow path comprises at least one of the viscosity and the density of the fluid.