Conductivity based autonomous inflow control device

Abstract

Introduced herein are a flow control system and a method for operating the flow control system that autonomously controls an inflow of fluid into production tubing in a wellbore based on conductivity or resistivity of the fluid that tries to enter the production tubing. By letting the conductivity of the fluid to open and close the control circuit that controls the operation of the actuator, the introduced flow control system is able to automate the inflow control of the fluid and minimize a number of electric components required. With a reduced number of electronics, the introduced system is more robust, reliable and stable in the extreme conditions inside a wellbore than other conventional flow control system.

1 . A method for controlling an inflow of fluid into production tubing in a wellbore, comprising:
 receiving fluid between terminals of a control circuit;   decreasing an inflow of the fluid into the production tubing using an actuator when the control circuit is closed;   increasing the inflow of the fluid into the production tubing using the actuator when the control circuit is open; and   powering the actuator off using an actuator circuit when a blocking member arrives at a less-open position, wherein said actuator circuit does not include an integrated circuit, and wherein the control circuit is closed when the fluid is conductive, and the control circuit is open when the fluid is non-conductive.   
     
     
         2 . The method of  claim 1 , wherein the decreasing the inflow using the actuator includes moving the blocking member from an open position to the less-open position. 
     
     
         3 . (canceled) 
     
     
         4 . The method of  claim 1 , wherein the powering the actuator off when the blocking member arrives at the less-open position includes opening the actuator circuit that provides a current to the actuator when the blocking member arrives at the less-open position. 
     
     
         5 . The method of  claim 1 , wherein when the fluid is conductive, the fluid is water. 
     
     
         6 . The method of  claim 1 , wherein the increasing the inflow using the actuator includes moving the blocking member from the less-open position to an open position. 
     
     
         7 . The method of  claim 6 , further comprising powering the actuator off using the actuator circuit when the blocking member arrives at the open position. 
     
     
         8 . The method of  claim 7 , wherein the powering the actuator off when the blocking member arrives at the open position includes opening the actuator circuit that provides a current to the actuator when the blocking member arrives at the open position. 
     
     
         9 . The method of  claim 1 , wherein when the fluid is non-conductive, the fluid is oil. 
     
     
         10 . An actuator assembly for controlling an inflow of fluid into production tubing in a wellbore, comprising:
 a control circuit including terminals positioned in the wellbore to receive fluid between the terminals; and   an actuator configured to decrease an inflow of the fluid into the production tubing when the control circuit is closed and increase the inflow of the fluid into the production tubing when the control circuit is open;   an actuator circuit configured to power the actuator off when a blocking member arrives at a less-open position from an open position, wherein said actuator circuit does not include an integrated circuit, and wherein the control circuit is closed when the fluid is conductive, and the control circuit is open when the fluid is non-conductive.   
     
     
         11 . The actuator assembly of  claim 10 , wherein the actuator is configured to decrease the inflow by moving the blocking member from the open position to the less-open position. 
     
     
         12 . (canceled) 
     
     
         13 . The actuator assembly of  claim 10 , wherein the actuator circuit includes a limit switch configured to open the actuator circuit when the blocking member arrives at the less-open position from the open position. 
     
     
         14 . The actuator assembly of  claim 10 , when the fluid is conductive, the fluid is water. 
     
     
         15 . The actuator assembly of  claim 10 , wherein the actuator is configured to increase the inflow by moving the blocking member from the less-open position to the open position. 
     
     
         16 . The actuator assembly of  claim 10 , wherein the actuator circuit is further configured to power the actuator off when the blocking member arrives at the open position from the less-open position. 
     
     
         17 . The actuator assembly of  claim 16 , wherein the actuator circuit includes a limit switch configured to open the actuator circuit when the blocking member arrives at the open position from the less-open position. 
     
     
         18 . The actuator assembly of  claim 16 , wherein the control circuit does not include an integrated circuit. 
     
     
         19 . The actuator assembly of  claim 10 , when the fluid is non-conductive, the fluid is oil. 
     
     
         20 . A flow control system for controlling an inflow of fluid into production tubing in a wellbore, comprising:
 a housing located between an inside wall of the wellbore and an outside wall of the production tubing and including a first fluid pathway that allows fluid to enter into the housing and a second fluid pathway that allows the fluid to enter into the production tubing;   a control circuit located inside the housing, the control circuit including terminals positioned across the first fluid pathway to receive fluid between the terminals; and   an actuator located inside the housing, the actuator configured to decrease an inflow of the fluid into production tubing when the control circuit is closed and increase the inflow of the fluid into the production tubing when the control circuit is open;   wherein the control circuit is closed when the fluid is conductive, and the control circuit is open when the fluid is non-conductive.   
     
     
         21 . The flow control system of  claim 20 , further comprising a blocking member, and wherein the actuator is configured to decrease the inflow by moving the blocking member from an open position to a less-open position that blocks the second fluid pathway and increase the inflow by moving the blocking member from the less-open position to the open position that exposes the second fluid pathway. 
     
     
         22 . The flow control system of  claim 21 , wherein the actuator includes a motor and the blocking member includes a valve that is rotatably coupled to the motor. 
     
     
         23 . The flow control system of  claim 22 , wherein the actuator is configured to move the blocking member from the open position to the less-open position by rotating the valve in one direction and move the blocking member from the less-open position to the open position by rotating the valve in other direction. 
     
     
         24 . The flow control system of  claim 21 , wherein the actuator includes a solenoid and the blocking member includes a piston that is retractably coupled to the solenoid. 
     
     
         25 . The flow control system of  claim 24 , wherein the actuator is configured to move the blocking member from the open position to the less-open position by applying an annulus pressure to one side of the piston and a tubing pressure to other side of the piston and to move the blocking member from the less-open position to the open position by applying the annulus pressure to the other side and the tubing pressure to the one side.