Pumpjack torque fill estimation

Abstract

The fill of a downhole pump of a pumpjack or other system may be estimated based on a dynamically changing a reference torque or force curve and actual torque or force measurements during at least a portion of a pump stroke. Using various techniques, the reference curve may dynamically change over time to take into account slowly changing operating conditions. Moreover, the reference curve and/or the measurements may be adjusted to ensure that the estimated and/or reported pump fill does not exceed 100 percent of pump capacity.

1 . A method for estimating pump fill, comprising:
 receiving data representing a series of torque or force measurements through a portion of a stroke of a pump;   determining, by a computer, a reference torque or force curve based on a previous reference curve and the series of torque or force measurements; and   determining, by the computer, an estimated pump fill of the pump based on the reference curve and the series of measurements.   
     
     
         2 . The method of  claim 1 , further comprising determining a peak measurement of the series of measurements, wherein determining the reference curve comprises determining a peak of the reference curve based on a peak of the previous reference curve and the peak measurement. 
     
     
         3 . The method of  claim 2 , wherein determining the peak of the reference curve comprises determining the peak of the reference curve based on a difference between the peak of the previous reference curve and the peak measurement. 
     
     
         4 . The method of  claim 1 , further comprising:
 determining a first area represented by the series of measurements; and   determining a second area represented by the reference curve,   wherein determining the estimated pump fill comprises determining the estimated pump fill based on a difference between the first and second areas.   
     
     
         5 . The method of  claim 1 , further comprising:
 determining whether any portion of the determined reference curve has values smaller than a corresponding subset of the series of measurements; and   for any determined said portion, adjusting said portion of the determined reference curve so that said portion no longer has values smaller than the corresponding subset of the series of measurements,   wherein said determining the estimated pump fill is performed after said adjusting.   
     
     
         6 . The method of  claim 1 , wherein the portion of the stroke of the pump is at least a portion of a down stroke of the pump. 
     
     
         7 . The method of  claim 1 , further comprising displaying a human-readable indication of the determined estimated pump fill. 
     
     
         8 . The method of  claim 1 , wherein the pump is a downhole pump of a pumpjack system, and wherein the measurements represent torque or force experienced by the pumpjack system. 
     
     
         9 . The method of  claim 1 , wherein the computer comprises a programmable logic controller. 
     
     
         10 . A computer for estimating pump fill, comprising:
 a processor; and   a non-transitory computer-readable medium storing computer-executable instructions for performing a method, such that when executed, the computer-executable instructions cause the computer to perform steps comprising:
 receiving data representing a series of torque or force measurements through a portion of a stroke of a pump, 
 determining a reference torque or force curve based on a previous reference curve and the series of torque or force measurements, and 
 determining an estimated pump fill of the pump based on the reference curve and the series of measurements. 
   
     
     
         11 . The computer of  claim 10 , wherein the steps further comprise determining a peak measurement of the series of measurements, wherein determining the reference curve comprises determining a peak of the reference curve based on a peak of the previous reference curve and the peak measurement. 
     
     
         12 . The computer of  claim 11 , wherein determining the peak of the reference curve comprises determining the peak of the reference curve based on a difference between the peak of the previous reference curve and the peak measurement. 
     
     
         13 . The computer of  claim 10 , wherein the steps further comprise:
 determining a first area represented by the series of measurements; and   determining a second area represented by the reference curve,   wherein determining the estimated pump fill comprises determining the estimated pump fill based on a difference between the first and second areas.   
     
     
         14 . The computer of  claim 10 , wherein the steps further comprise:
 determining whether any portion of the determined reference curve has values smaller than a corresponding subset of the series of measurements; and   for any determined said portion, adjusting said portion of the determined reference curve so that said portion no longer has values smaller than the corresponding subset of the series of measurements,   wherein said determining the estimated pump fill is performed after said adjusting.   
     
     
         15 . The computer of  claim 10 , wherein the portion of the stroke of the pump is at least a portion of a down stroke of the pump. 
     
     
         16 . The computer of  claim 10 , further comprising a display device, wherein the steps further comprise causing the display device to display a human-readable indication of the determined estimated pump fill. 
     
     
         17 . The computer of  claim 10 , wherein the pump is a downhole pump of a pumpjack system, and wherein the measurements represent torque or force experienced by the pumpjack system. 
     
     
         18 . The computer of  claim 10 , wherein the processor comprises a programmable logic controller. 
     
     
         19 . A non-transitory computer-readable medium storing computer-executable instructions for estimating pump fill, such that when executed, the computer-executable instructions cause a computer to perform steps comprising:
 receiving data representing a series of torque or force measurements through a portion of a stroke of a pump;   determining a reference torque or force curve based on a previous reference curve and the series of torque or force measurements; and   determining an estimated pump fill of the pump based on the reference curve and the series of measurements.   
     
     
         20 . The non-transitory computer-readable medium of  claim 19 , wherein the steps further comprise determining a peak measurement of the series of measurements, wherein determining the reference curve comprises determining a peak of the reference curve based on a peak of the previous reference curve and the peak measurement. 
     
     
         21 . The non-transitory computer-readable medium of  claim 20 , wherein determining the peak of the reference curve comprises determining the peak of the reference curve based on a difference between the peak of the previous reference curve and the peak measurement. 
     
     
         22 . The non-transitory computer-readable medium of  claim 19 , wherein the steps further comprise:
 determining a first area represented by the series of measurements; and   determining a second area represented by the reference curve,   wherein determining the estimated pump fill comprises determining the estimated pump fill based on a difference between the first and second areas.   
     
     
         23 . The non-transitory computer-readable medium of  claim 19 , wherein the steps further comprise:
 determining whether any portion of the determined reference curve has values smaller than a corresponding subset of the series of measurements; and   for any determined said portion, adjusting said portion of the determined reference curve so that said portion no longer has values smaller than the corresponding subset of the series of measurements,   wherein said determining the estimated pump fill is performed after said adjusting.   
     
     
         24 . The non-transitory computer-readable medium of  claim 19 , wherein the portion of the stroke of the pump is at least a portion of a down stroke of the pump. 
     
     
         25 . The non-transitory computer-readable medium of  claim 19 , wherein the steps further comprise causing a display device to display a human-readable indication of the determined estimated pump fill. 
     
     
         26 . The non-transitory computer-readable medium of  claim 19 , wherein the pump is a downhole pump of a pumpjack system, and wherein the measurements represent torque or force experienced by the pumpjack system.