Downhole Fluid Flow Control System

Abstract

A downhole fluid flow control system includes one or more fluid control modules each having upstream and downstream sides with parallel main and secondary fluid pathways extending between the upstream and downstream sides. A valve element disposed within the main fluid pathway has open and closed positions. A viscosity discriminator including a viscosity sensitive channel forms at least a portion of the secondary fluid pathway. A differential pressure switch operable to open and close the valve element includes a first pressure signal from the upstream side, a second pressure signal from the downstream side and a third pressure signal from the secondary fluid pathway. The magnitude of the third signal is dependent upon the viscosity of the fluid flowing through the secondary fluid pathway such that changes in fluid viscosity operate the differential pressure switch, thereby controlling fluid flow through the main fluid pathway of each module.

What is claimed is: 
     
         1 . A downhole fluid flow control system comprising:
 at least one flow control tubular; and   a plurality of autonomous inflow control devices coupled to the at least one flow control tubular, the plurality of autonomous inflow control devices including a first autonomous inflow control device having a first valve element and a first differential pressure switch that is operable to shift the first valve element between open and closed positions and a second autonomous inflow control device having a second valve element and a second differential pressure switch that is operable to shift the second valve element between open and closed positions;   wherein, the first differential pressure switch is configured to open the first valve element responsive to a fluid flowing through the first autonomous inflow control device that has at least a first viscosity and is configured to close the first valve element responsive to a fluid flowing through the first autonomous inflow control device that has less than the first viscosity;   wherein, the second differential pressure switch is configured to open the second valve element responsive to a fluid flowing through the second autonomous inflow control device that has at least a second viscosity and is configured to close the second valve element responsive to a fluid flowing through the second autonomous inflow control device that has less than the second viscosity; and   wherein, the second viscosity is different from the first viscosity.   
     
     
         2 . The flow control system as recited in  claim 1  wherein, the at least one flow control tubular further comprises a plurality of flow control tubulars. 
     
     
         3 . The flow control system as recited in  claim 1  wherein, the at least one flow control tubular further comprises at least one flow control screen. 
     
     
         4 . The flow control system as recited in  claim 1  wherein, the at least one flow control tubular further comprises a plurality of flow control screens. 
     
     
         5 . The flow control system as recited in  claim 1  wherein, the first autonomous inflow control device has a first upstream side and a first downstream side with a first main fluid pathway in parallel with a first secondary fluid pathway each extending between the first upstream and first downstream sides, the first valve element configured to allow fluid flow through the first main fluid pathway in the open position and configured to prevent fluid flow through the first main fluid pathway in the closed position; and
 wherein, the second autonomous inflow control device has a second upstream side and a second downstream side with a second main fluid pathway in parallel with a second secondary fluid pathway each extending between the second upstream and second downstream sides, the second valve element configured to allow fluid flow through the second main fluid pathway in the open position and configured to prevent fluid flow through the second main fluid pathway in the closed position. 
 
     
     
         6 . The flow control system as recited in  claim 5  wherein, the first differential pressure switch is configured to receive a first pressure signal from a first location along the first secondary fluid pathway that biases the first valve element toward the closed position;
 wherein, the second differential pressure switch is configured to receive a second pressure signal from a second location along the second secondary fluid pathway that biases the second valve element toward the closed position; and 
 wherein, the first location along the first secondary fluid pathway is different relative to the second location along the second secondary fluid pathway. 
 
     
     
         7 . The flow control system as recited in  claim 6  wherein, the first location along the first secondary fluid pathway is upstream relative to the second location along the second secondary fluid pathway. 
     
     
         8 . The flow control system as recited in  claim 6  wherein, the first location along the first secondary fluid pathway is downstream relative to the second location along the second secondary fluid pathway. 
     
     
         9 . The flow control system as recited in  claim 6  wherein, the first secondary fluid pathway includes a first viscosity sensitive channel and a first non-viscosity sensitive channel; and
 wherein, the second secondary fluid pathway includes a second viscosity sensitive channel and a second non-viscosity sensitive channel. 
 
     
     
         10 . The flow control system as recited in  claim 9  wherein, the first location along the first secondary fluid pathway is an upstream location along the first non-viscosity sensitive channel; and
 wherein, the second location along the second secondary fluid pathway is a downstream location along the second non-viscosity sensitive channel. 
 
     
     
         11 . The flow control system as recited in  claim 9  wherein, the first location along the first secondary fluid pathway is a midstream location along the first non-viscosity sensitive channel; and
 wherein, the second location along the second secondary fluid pathway is a downstream location along the second non-viscosity sensitive channel. 
 
     
     
         12 . The flow control system as recited in  claim 9  wherein, the first location along the first secondary fluid pathway is a midstream location along the first non-viscosity sensitive channel; and
 wherein, the second location along the second secondary fluid pathway is an upstream location along the second non-viscosity sensitive channel. 
 
     
     
         13 . The flow control system as recited in  claim 9  wherein, the first viscosity sensitive channel further comprises a first tortuous path; and
 wherein, the second viscosity sensitive channel further comprises a second tortuous path. 
 
     
     
         14 . The flow control system as recited in  claim 5  wherein, the first differential pressure switch is configured to receive a first upstream pressure signal from the first upstream side, a first downstream pressure signal from the first downstream side and a first secondary pressure signal from the first secondary fluid pathway, the first upstream pressure signal and first the downstream pressure signal biasing the first valve element toward the open position, the first secondary pressure signal biasing the first valve element toward the closed position; and
 wherein, the second differential pressure switch is configured to receive a second upstream pressure signal from the second upstream side, a second downstream pressure signal from the second downstream side and a second secondary pressure signal from the second secondary fluid pathway, the second upstream pressure signal and second the downstream pressure signal biasing the second valve element toward the open position, the second secondary pressure signal biasing the second valve element toward the closed position. 
 
     
     
         15 . The flow control system as recited in  claim 14  wherein, a magnitude of the first secondary pressure signal is dependent upon the viscosity of the fluid flowing through the first secondary fluid pathway; and
 wherein, a magnitude of the second secondary pressure signal is dependent upon the viscosity of the fluid flow through the second secondary fluid pathway. 
 
     
     
         16 . The flow control system as recited in  claim 15  wherein, the magnitude of the first secondary pressure signal increases with decreasing viscosity of the fluid flowing through the first secondary fluid pathway; and
 wherein, the magnitude of the second secondary pressure signal increases with decreasing viscosity of the fluid flowing through the second secondary fluid pathway. 
 
     
     
         17 . The flow control system as recited in  claim 15  wherein, the first differential pressure switch is configured to open the first valve element responsive to the fluid flowing through the first secondary fluid pathway having at least the first viscosity and is configured to close the first valve element responsive to the fluid flowing through the first secondary fluid pathway having less than the first viscosity; and
 wherein, the second differential pressure switch is configured to open the second valve element responsive to the fluid flowing through the second secondary fluid pathway having at least the second viscosity and is configured to close the second valve element responsive to the fluid flowing through the second secondary fluid pathway having less than the second viscosity. 
 
     
     
         18 . A downhole fluid flow control system comprising:
 a tubular string including first and second flow control tubulars;   a plurality of autonomous inflow control devices including a first autonomous inflow control device coupled to the first flow control tubular and a second autonomous inflow control device coupled to the second flow control tubular, the first autonomous inflow control device having a first valve element and a first differential pressure switch that is operable to shift the first valve element between open and closed positions, the second autonomous inflow control device having a second valve element and a second differential pressure switch that is operable to shift the second valve element between open and closed positions;   wherein, the first differential pressure switch is configured to open the first valve element responsive to a fluid flowing through the first autonomous inflow control device that has at least a first viscosity and is configured to close the first valve element responsive to a fluid flowing through the first autonomous inflow control device that has less than the first viscosity;   wherein, the second differential pressure switch is configured to open the second valve element responsive to a fluid flowing through the second autonomous inflow control device that has at least a second viscosity and is configured to close the second valve element responsive to a fluid flowing through the second autonomous inflow control device that has less than the second viscosity; and   wherein, the second viscosity is different from the first viscosity.   
     
     
         19 . A downhole fluid flow control system comprising:
 a flow control tubular; and   a plurality of autonomous inflow control devices coupled to the flow control tubular, the plurality of autonomous inflow control devices including a first autonomous inflow control device having a first valve element and a first differential pressure switch that is operable to shift the first valve element between open and closed positions and a second autonomous inflow control device having a second valve element and a second differential pressure switch that is operable to shift the second valve element between open and closed positions;   wherein, the first differential pressure switch is configured to open the first valve element responsive to a fluid flowing through the first autonomous inflow control device that has at least a first viscosity and is configured to close the first valve element responsive to a fluid flowing through the first autonomous inflow control device that has less than the first viscosity;   wherein, the second differential pressure switch is configured to open the second valve element responsive to a fluid flowing through the second autonomous inflow control device that has at least a second viscosity and is configured to close the second valve element responsive to a fluid flowing through the second autonomous inflow control device that has less than the second viscosity; and   wherein, the second viscosity is different from the first viscosity.   
     
     
         20 . The flow control system as recited in  claim 19  wherein, the at least one flow control tubular further comprises at least one flow control screen.