Detection And Identification Of Fluid Pumping Anomalies

Abstract

A method for monitoring operation of a pumping system for pumping anomalies is provided. In one embodiment, the method includes operating a pump of a downhole tool to pump fluid through the downhole tool and continually measuring an operational parameter of the downhole tool over a period of time during pumping of the fluid through the downhole tool. The measurements of the operational parameter can be filtered, and the filtered measurements can be monitored to enable detection of pumping anomalies in the downhole tool. Additional systems, devices, and methods are also disclosed.

1 . A method comprising:
 operating a pump of a downhole tool to pump fluid through the downhole tool;   continually measuring an operational parameter of the downhole tool over a period of time during pumping of the fluid through the downhole tool;   filtering the measurements of the operational parameter; and   monitoring the filtered measurements of the operational parameter to enable detection of pumping anomalies in the downhole tool.   
     
     
         2 . The method of  claim 1 , wherein operating the pump of the downhole tool includes operating a bidirectional displacement pump having a reciprocating piston and monitoring the filtered measurements of the operational parameter enables detection of half-stroking by the bidirectional displacement pump. 
     
     
         3 . The method of  claim 2 , comprising identifying one or more potentially faulty valves in the downhole tool based on position data of the reciprocating piston and the detection of the half-stroking by the bidirectional displacement pump. 
     
     
         4 . The method of  claim 1 , wherein filtering the measurements of the operational parameter includes applying a median filter to the measurements of the operational parameter. 
     
     
         5 . The method of  claim 4 , wherein the pump has a displacement chamber for receiving the fluid and applying the median filter to the measurements of the operational parameter includes applying the median filter to measurements of the operational parameter within a time window having a size that is less than the volume of the displacement unit chamber divided by an operated flow rate of the pump during the period of time. 
     
     
         6 . The method of  claim 1 , wherein the operational parameter includes inlet pressure measured within the downhole tool upstream from the pump and monitoring the filtered measurements of the operational parameter includes comparing filtered inlet pressure measurements to a formation pressure for a formation from which the fluid is drawn by the downhole tool. 
     
     
         7 . The method of  claim 1 , wherein the operational parameter includes outlet pressure measured within the downhole tool downstream from the pump and monitoring the filtered measurements of the operational parameter includes comparing filtered outlet pressure measurements to a wellbore pressure for a wellbore in which the downhole tool is disposed. 
     
     
         8 . The method of  claim 1 , wherein the operational parameter includes alternator current provided by an alternator to a motor for driving the pump and monitoring the filtered measurements of the operational parameter includes comparing filtered alternator current measurements to a current threshold value, or wherein the operational parameter includes pump flow rate and monitoring the filtered measurements of the operational parameter includes comparing filtered pump flow rate measurements to a flow rate threshold value. 
     
     
         9 . The method of  claim 1 , wherein continually measuring the operational parameter, filtering the measurements of the operational parameter, and monitoring the filtered measurements of the operational parameter include continually measuring multiple operational parameters over the period of time, filtering the measurements of the multiple operational parameters, and monitoring the filtered measurements of the multiple operational parameters to enable detection of pumping anomalies in the downhole tool. 
     
     
         10 . The method of  claim 9 , comprising aggregating results of the monitoring of the filtered measurements of two or more of the multiple operational parameters to reduce the likelihood of false positives in the detection of pumping anomalies in the downhole tool. 
     
     
         11 . The method of  claim 1 , wherein continually measuring the operational parameter of the downhole tool over the period of time during pumping of the fluid through the downhole tool includes measuring the operational parameter at a rate between 1 Hz and 10 Hz. 
     
     
         12 . A method comprising:
 moving a piston within a pump in a periodic manner;   drawing fluid into a first chamber of the pump and expelling fluid from a second chamber of the pump by moving the piston in a first axial direction;   changing the direction of movement of the piston from the first axial direction to a second axial direction opposite the first axial direction so as to draw fluid into the second chamber of the pump and expel fluid from the first chamber of the pump;   obtaining measurements related to the operation of the pump for a time window that is less than one-half of the period of the movement of the piston within the pump;   filtering the measurements obtained for the time window; and   determining whether a fault condition exists for the pump based on the filtered measurements.   
     
     
         13 . The method of  claim 12 , wherein filtering the measurements obtained for the time window includes applying a trimmed mean filter to the measurements obtained for the time window. 
     
     
         14 . The method of  claim 12 , wherein obtaining measurements related to the operation of the pump includes obtaining at least one of an inlet pressure upstream of the pump, an outlet pressure downstream of the pump, or an alternator current. 
     
     
         15 . The method of  claim 12 , wherein determining whether the fault condition exists for the pump based on the filtered measurements includes determining whether the magnitude of the difference between a filtered pressure measurement and a reference pressure is below a threshold value. 
     
     
         16 . The method of  claim 12 , wherein the pump is disposed in a downhole tool. 
     
     
         17 . A downhole tool comprising:
 an intake configured to receive formation fluid within a flowline of the downhole tool;   a pump in fluid communication with the flowline so as to enable the pump to draw the formation fluid into the downhole tool via the flowline and to expel the formation fluid from the downhole tool;   a sensor configured to measure an operational parameter of the downhole tool; and   a controller operable to detect pumping anomalies during operation of the pump based on filtered measurements of the operational parameter collected via the sensor.   
     
     
         18 . The downhole tool of  claim 17 , wherein the controller is operable to filter measurements of the operational parameter collected via the sensor. 
     
     
         19 . The downhole tool of  claim 18 , wherein the controller is operable to apply a median filter to the measurements of the operational parameter collected via the sensor and to compare the filtered measurements of the operational parameter to a threshold value to detect the pumping anomalies. 
     
     
         20 . The downhole tool of  claim 17 , comprising a plurality of check valves in fluid communication with the pump, wherein the controller is operable to identify a proper subset of potentially faulty check valves from the plurality of check valves based on a detected pumping anomaly.