Monitoring Flow Past Submersible Well Pump Motor with Sail Switch

Abstract

An electric submersible well pumping system (ESP) has a sail switch to measure fluid speed within the wellbore in the areas surrounding the motor to thereby determine fluid speed adjacent the motor. A controller controls the operation of the motor based on the inputs of the sail switch to thereby avoid overheating the motor to preserve motor longevity. The sail switch has a paddle that switches from a first toggle position to a second toggle position in response to a selected fluid speed.

1 . An apparatus for pumping fluid from a cased well, comprising:
 an electrical submersible pump assembly (ESP) having a pump and an electrical motor positioned within casing of the cased well;   at least one sail switch mounted to the ESP, the sail switch having an external paddle that moves in response to a change in fluid speed of well fluid flowing past the motor from a first toggle position to a second toggle position;   a controller at a surface position of the well that is electrically linked to the sail switch for performing a motor control function in response to the change from the first toggle position to the second toggle position.   
     
     
         2 . The system of  claim 1 , wherein said at least one sail switch comprises a plurality of sail switches, each one of the plurality of sail switches set to change toggle position in respect to a different fluid speed of the well fluid flowing past the motor. 
     
     
         3 . The system of  claim 1 , further comprising a toggling status indicator at the controller that indicates whether the sail switch is in the first position or the second position. 
     
     
         4 . The system of  claim 1 , wherein the sail switch is mounted below the motor. 
     
     
         5 . The system of  claim 4 , further comprising an extension member that supports the sail switch a selected distance below the motor. 
     
     
         6 . The system of  claim 1 , wherein an increase in the fluid speed of the well fluid above a selected minimum can cause the sail switch to move from the first toggle position to the second toggle position and a decrease in the fluid speed below the selected minimum can cause the sail switch to move from the second toggle position to the first toggle position. 
     
     
         7 . The system of  claim 1 , wherein the controller shuts off the motor if the fluid speed, over a selected time interval, is inadequate to move the sail switch from the first toggle position to the second toggle position. 
     
     
         8 . An apparatus for pumping fluid from a cased well, comprising:
 an electrical submersible pump assembly (ESP) having a pump and an electrical motor positioned within casing of the cased well;   a housing mounted to the ESP below the motor that allows for the ingress and egress of fluids moving in the cased well;   at least one sail switch mounted between the housing walls, the sail switch having an external paddle that moves in response to a change in fluid speed of well fluid flowing past the motor, an increase in the fluid speed of the well fluid above a selected minimum can cause the sail switch paddle to move from the first toggle position to the second toggle position and a decrease in the fluid speed below the selected minimum can cause the sail switch paddle to move from the second toggle position to the first toggle position;   a controller at a surface of the well that is electrically linked to the sail switch for performing a motor control function in response to the change from the first toggle position to the second toggle position.   
     
     
         9 . The system of  claim 8 , wherein said at least one sail switch comprises a plurality of sail switches, each set to change a toggle position in respect to a different fluid speed of the well fluid flowing past the motor. 
     
     
         10 . The system of  claim 8 , further comprising an extension member that supports the sail switch a selected distance below the motor. 
     
     
         11 . The system of  claim 8 , wherein the controller shuts off the motor if the fluid speed over a selected time interval is inadequate to move the sail switch from the first toggle position to the second toggle position. 
     
     
         12 . The system of  claim 8 , further comprising a toggling status indicator at the controller that indicates whether the sail switch is in the first position or the second position. 
     
     
         13 . The system of  claim 8 , wherein the sail switch has at least three toggle positions, an increase in the fluid speed of the well fluid above a selected minimum can cause the sail switch to move from the first toggle position to the second toggle position and an increase above a second selected minimum can cause the sail switch to move from the second toggle position to the third toggle position, a decrease in the fluid speed below the second selected minimum can cause the sail switch to move from the third toggle position to the second toggle position, a decrease in the fluid speed below the selected minimum can cause the sail switch to move from the second toggle position to the first toggle position. 
     
     
         14 . The system of  claim 13 , further comprising a toggling status indicator at the controller that indicates whether the sail switch is in the first position, the second position, or the third position. 
     
     
         15 . A method for pumping well fluid for a well, comprising:
 mounting at least one sail switch to an electrical submersible pumping assembly (ESP) having a pump, an electric motor, and a surface controller;   then lowering the ESP into the well;   supplying power to the motor to operate the pump;   causing the well fluid flowing past the motor to move the sail switch from a first toggle position to a second toggle position if a fluid speed of well fluid reaches a selected minimum; and   the surface controller performing a motor control function in response to the change from the first toggle position to the second toggle position.   
     
     
         16 . A method according to  claim 15 , wherein the motor control function comprises providing a visible indication at the controller of the sail switches toggle position. 
     
     
         17 . A method according to  claim 15 , wherein the motor control function comprises shutting down the motor. 
     
     
         18 . A method according to  claim 15 , further comprising:
 detecting downhole fluid speed with a plurality of sail switches, each sail switch toggling at a different selected minimum fluid speed.   
     
     
         19 . A method according to  claim 15 , further comprising:
 a sail switch toggling in response to a decrease in the fluid speed below the selected minimum that causes the sail switch to move from the second toggle position to the first toggle position.   
     
     
         20 . A method according to  claim 15 , further comprising:
 mounting at least one sail switch to an electrical submersible pumping assembly (ESP) beneath the motor.