Method of detecting and breaking gas locks in an electric submersible pump

Abstract

A method of breaking a gas lock in an electrical submersible pump, comprising: a) monitoring a measured value related to the electrical current used by a pump motor connected to and providing power to the pump; b) comparing the measured value to a threshold value to detect the occurrence of gas lock conditions; and when those conditions are detected; c) sending an override signal to immediately reduce the flow to the pump for a set period of time; and d) comparing the measured value related to the electrical current to the threshold value at the end of the set period of time, and if gas lock conditions are not detected, then increasing the power to the pump.

1 . A method of breaking a gas lock in an electrical submersible pump, comprising:
 a. monitoring a derived value related to the electrical current used by a pump motor connected to and providing power to the pump;   b. comparing the derived value to a threshold value to detect the occurrence of gas lock conditions; and when those conditions are detected;   c. sending an override signal to immediately reduce the flow to the pump for a set period of time; and   d. comparing the derived value related to the electrical current to the threshold value at the end of the set period of time, and if gas lock conditions are not detected, then increasing the power to the pump.   
     
     
         2 . The method of  claim 1  wherein the derived value is the running standard deviation of the pump motor amps. 
     
     
         3 . The method of  claim 1  wherein the override signal is a signal that is normally at maximum frequency, but is changed to a pre-defined minimum frequency when gas lock conditions are detected. 
     
     
         4 . The method of  claim 3  wherein the override signal and the pressure control signal are directed through a low signal selector. 
     
     
         5 . The method of  claim 1  wherein an operator can override the set period of time and force the comparison of step d) at any time after the override signal is sent. 
     
     
         6 . The method of  claim 1  wherein the power to the pump is increased according to a specified ramp rate. 
     
     
         7 . The method of  claim 1  further comprising continuing to send the override signal for a second set period of time if gas lock conditions are detected during step d) and then comparing the derived value related to the electrical current to the threshold value at the end of the second set period of time, and if gas lock conditions are not detected, then increasing the power to the pump. 
     
     
         8 . The method of  claim 8  further comprising continuing to send the override for subsequent set periods of time until gas lock conditions are not detected.