Detection and mitigation of detrimental operating conditions during pumpjack pumping

Abstract

A motor-driven pumpjack is operated continuously while receiving sensory feedback from one or more sensors. In response to feedback indicating a detrimental operating condition, and while continuing to operate the pumpjack, one or more speed adjustments are made to specific control periods within the motor pumping cycle. The automated control optimizes flow while reacting to detrimental and changing conditions.

What is claimed is: 
     
         1 . A method of operating a pumpjack continuously over a sequence of pump stroke cycles, the method comprising:
 energizing an electric motor to operate the pumpjack over a first pump stroke cycle, according to a first motor speed profile comprising a plurality of target motor speeds corresponding to each of a plurality of discrete control periods within the first pump stroke cycle;   receiving sensory feedback during the first pump stroke cycle from one or more sensors mounted to monitor at least one operating condition of the pumpjack, the sensory feedback comprising data collected during operation of the motor according to the first motor speed profile;   detecting, while continuing to operate the pumpjack, a detrimental operating condition within the first pump stroke cycle based on the sensory feedback;   in response to detecting the detrimental operating condition, determining one or more speed adjustment values corresponding to a limited subset of the plurality of discrete control periods;   altering the first motor speed profile based on the one or more adjustment values to provide a second motor speed profile; and   operating the electric motor over a second pump stroke cycle, according to the second motor speed profile.   
     
     
         2 . The method of  claim 1 , wherein the first motor speed profile comprises a predetermined default setting. 
     
     
         3 . The method of  claim 1 , wherein the first motor speed profile comprises an altered version of a motor speed profile utilized in a previous pump stroke cycle of the sequence. 
     
     
         4 . The method of  claim 1 , wherein the plurality of discrete control periods of the first pump stroke cycle comprise at least 100 control periods. 
     
     
         5 . The method of  claim 1 , wherein one or more of the plurality of discrete control periods of the first pump stroke cycle comprise a time duration of between about 5 and 100 milliseconds. 
     
     
         6 . The method of  claim 1 , wherein each of the plurality of discrete control periods of the first pump stroke comprise an identical time duration. 
     
     
         7 . The method of  claim 1 , wherein at least one of the sensors comprises a load sensor. 
     
     
         8 . The method of  claim 7 , wherein the load sensor is responsive to load of a polish rod of the pumpjack. 
     
     
         9 . The method of  claim 1 , wherein at least one of the sensors comprises a crank rotation sensor. 
     
     
         10 . The method of  claim 1 , wherein at least one of the sensors comprises a motor shaft position sensor. 
     
     
         11 . The method of  claim 1 , wherein at least one of the sensors comprises a motor current sensor. 
     
     
         12 . The method of  claim 1 , wherein detecting the detrimental operating condition comprises constructing a data structure relating position to load with respect to a polish rod of the pumpjack over the first pump stroke cycle based on the sensory feedback. 
     
     
         13 . The method of  claim 12 , wherein detecting the detrimental operating condition comprises comparing the data structure to one or more predetermined load limits. 
     
     
         14 . The method of  claim 13 , wherein at least one of the predetermined load limits corresponds to structural integrity of the polish rod. 
     
     
         15 . The method of  claim 12 , wherein at least one of the predetermined load limits corresponds to structural integrity of a gear box coupled to the motor and the polish rod. 
     
     
         16 . The method of  claim 12 , wherein detecting the detrimental operating condition further comprises identifying an abrupt load spike based on the data structure. 
     
     
         17 . The method of  claim 12 , wherein the data structure comprises a dynamometer surface card. 
     
     
         18 . The method of  claim 12 , wherein the data structure comprises a downhole pump card. 
     
     
         19 . The method of  claim 1 , wherein determining the one or more speed adjustment values comprises selecting a speed adjustment value to increase the target motor speed at a control period within the second pump stroke cycle preceding or subsequent to a different control period where the detrimental operating condition is likely to reoccur. 
     
     
         20 . The method of  claim 1 , wherein determining the one or more speed adjustment values comprises selecting a speed adjustment value to decrease the target motor speed at a control period within the second pump stroke cycle where the detrimental operating condition is likely to reoccur. 
     
     
         21 . The method of  claim 1 , wherein determining the one or more speed adjustment values comprises selecting a speed adjustment value to decrease the target motor speed at a control period within the second pump stroke cycle preceding a different control period where the detrimental operating condition is likely to reoccur. 
     
     
         22 . The method of  claim 1 , wherein the electric motor comprises a regenerative drive, and wherein the method further comprises providing a breaking torque to control descent of a rod system of the pumpjack during a downstroke of each of the pump stroke cycles, while simultaneously converting kinetic energy of the rod system into electrical power. 
     
     
         23 . A method of operating a pumpjack, the method comprising:
 operating an electric motor of a pumpjack to pump fluid, according to a predetermined motor speed profile comprising a plurality of target motor speeds corresponding to each of a plurality of discrete control periods within a stroke cycle of the pumpjack, while receiving sensory feedback comprising data collected from one or more sensors mounted to monitor at least one operating condition of the pumpjack, wherein the predetermined motor speed profile corresponds to an optimized stroke timing curve determined during one or more previous stroke cycles of the pumpjack;   while continuing to operate the electric motor to pump fluid, increasing one or more of the plurality of target motor speeds over a plurality of stroke cycles until a detrimental operating condition is detected based on sensory feedback; and   in response to detecting the detrimental operating condition, and as the pumpjack continues to pump fluid, decreasing a subset of the plurality of target motor speeds selected based on a position of the detected detrimental operating condition within the stroke cycle.   
     
     
         24 . The method of  claim 23 , wherein the plurality of discrete control periods comprises at least 100 control periods. 
     
     
         25 . The method of  claim 23 , wherein one or more of the plurality of discrete control periods comprise a time duration of between about 5 and 100 milliseconds. 
     
     
         26 . The method of  claim 23 , wherein each of the plurality of discrete control periods comprise an identical time duration. 
     
     
         27 . The method of  claim 23 , wherein at least one of the sensors comprises a load sensor. 
     
     
         28 . The method of  claim 27 , wherein the load sensor is responsive to load of a polish rod of the pumpjack. 
     
     
         29 . The method of  claim 23 , wherein at least one of the sensors comprises a crank rotation sensor. 
     
     
         30 . The method of  claim 23 , wherein at least one of the sensors comprises a motor shaft position sensor. 
     
     
         31 . The method of  claim 23 , wherein at least one of the sensors comprises a motor current sensor. 
     
     
         32 . The method of  claim 23 , wherein incrementally increasing selected ones of the plurality of target motor speeds comprises incrementally increasing each of the plurality of target motor speeds according to a predetermined adjustment schedule. 
     
     
         33 . The method of  claim 23 , wherein the detrimental operating condition is detected by:
 constructing a data structure relating position to load with respect to a polish rod of the pumpjack over the stroke cycle based on the sensory feedback; and   comparing the data structure to one or more predetermined load limits.   
     
     
         34 . The method of  claim 33 , wherein at least one of the predetermined load limits corresponds to structural integrity of the polish rod. 
     
     
         35 . The method of  claim 33 , wherein at least one of the predetermined load limits corresponds to structural integrity of a gear box coupled to the motor and the polish rod. 
     
     
         36 . The method of  claim 23 , wherein the detrimental operating condition is detected by:
 constructing a data structure relating position to load with respect to a polish rod of the pumpjack over the stroke cycle based on the sensory feedback; and   identifying an abrupt load spike based on the data structure.   
     
     
         37 . The method of  claim 23 , wherein decreasing a subset of the plurality of target motor speeds comprises decreasing the target motor speed at one or more control periods preceding a different control period where the detrimental operating condition is likely to reoccur. 
     
     
         38 . The method of  claim 23 , wherein decreasing a subset of the plurality of target motor speeds comprises decreasing the target motor speed at the control period where the detrimental operating condition is likely to reoccur. 
     
     
         39 . The method of  claim 23 , wherein the electric motor comprises a regenerative drive, and wherein the method further comprises providing a breaking torque to control descent of a rod system of the pumpjack during a downstroke of each of the pump stroke cycles while simultaneously converting kinetic energy of the rod system into electrical power. 
     
     
         40 . A pumpjack motor system, comprising:
 an electric motor coupled to a gear box of a pumpjack;   one or more sensors mounted to monitor at least one operating condition of the pumpjack; and   a local controller coupled to the electric motor and the one or more sensors and operable, while the pumpjack continuously pumps fluid, to:
 control the motor according to a first motor speed profile comprising a plurality of target motor speeds corresponding to each of a plurality of discrete control periods within a single stroke cycle of the pumpjack; 
 receive sensory feedback from the one or more sensors, the sensory feedback comprising data, including load data, collected during operation of the motor according to the first motor speed profile; 
 automatically increment a first set of the target motor speeds corresponding to portions of the stroke cycle outside of a predetermined load limit, based on the load data; and 
 automatically decrement a second set of the target motor speeds corresponding to portions of the stroke cycle within the predetermined load limit, thereby generating a second motor speed profile; and to 
 control the motor according to the second motor speed profile. 
   
     
     
         41 . The pumpjack motor system of  claim 38 , wherein at least one of the sensors comprises a load sensor. 
     
     
         42 . The pumpjack motor system of  claim 41 , wherein the load sensor is responsive to load of a polish rod of the pumpjack. 
     
     
         43 . The pumpjack motor system of  claim 40 , wherein at least one of the sensors comprises a crank rotation sensor. 
     
     
         44 . The pumpjack motor system of  claim 41 , wherein at least one of the sensors comprises a motor shaft position sensor. 
     
     
         45 . The pumpjack motor system of  claim 40 , wherein at least one of the sensors comprises a motor current sensor. 
     
     
         46 . The pumpjack motor system of  claim 40 , wherein the controller is further configured to identify portions of the stroke cycle outside of the predetermined load limit by:
 constructing a data structure relating position to load with respect to a polish rod of the pumpjack over the stroke cycle based on the sensory feedback; and   comparing the data structure to the predetermined load limit.   
     
     
         47 . The pumpjack motor system of  claim 40 , wherein the predetermined load limit corresponds to structural integrity of the polish rod. 
     
     
         48 . The pumpjack motor system of  claim 40 , wherein the predetermined load limit corresponds to structural integrity of a gear box coupled to the motor and the polish rod. 
     
     
         49 . The pumpjack motor system of  claim 40 , wherein the electric motor comprises a regenerative drive configured to provide a breaking torque to control the descent of a rod system of the pumpjack during a downstroke of each stroke cycle, while simultaneously converting kinetic energy of the rod system into electrical power. 
     
     
         50 . A pumpjack motor system, comprising:
 an electric motor coupled to a gear box of a pumpjack;   one or more sensors mounted to monitor at least one operating condition of the pumpjack; and   a local controller coupled to the electric motor and the one or more sensors and operable, while the pumpjack continuously pumps fluid over two sequential pumping cycles, to:
 control the electric motor through a first of the two sequential pumping cycles, according to a first motor speed profile comprising a plurality of target motor speeds corresponding to respective portions of the pumpjack stroke cycle, while receiving sensory feedback from the one or more sensors; 
 detect a detrimental operating condition within the first pump stroke cycle based on the sensory feedback; 
 in response to the detection, automatically adjust one or more of the target motor speeds as a function of the sensory feedback, to generate an adjusted motor speed profile; and to 
 control the motor according to the adjusted motor speed profile during a second of the two sequential pumping cycles of the pumpjack. 
   
     
     
         51 . The pumpjack motor system of  claim 50 , wherein the first motor speed profile comprises a predetermined default setting. 
     
     
         52 . The pumpjack motor system of  claim 50 , wherein the first motor speed profile comprises an altered version of a motor speed profile utilized in a previous pump stroke cycle of the sequence. 
     
     
         53 . The pumpjack motor system of  claim 50 , wherein at least one of the sensors comprises a load sensor. 
     
     
         54 . The pumpjack motor system of  claim 53 , wherein the load sensor is responsive to load of a polish rod of the pumpjack. 
     
     
         55 . The pumpjack motor system of  claim 50 , wherein at least one of the sensors comprises a crank rotation sensor. 
     
     
         56 . The pumpjack motor system of  claim 50 , wherein at least one of the sensors comprises a motor shaft position sensor. 
     
     
         57 . The pumpjack motor system of  claim 50 , wherein at least one of the sensors comprises a motor current sensor. 
     
     
         58 . The pumpjack motor system of  claim 50 , wherein the local controller is operable to detect the detrimental operating condition by first constructing a data structure relating position to load with respect to a polish rod of the pumpjack over the first pump stroke cycle based on the sensory feedback. 
     
     
         59 . The pumpjack motor system of  claim 58 , wherein the local controller is operable to detect the detrimental operating condition by also comparing the data structure to one or more predetermined load limits. 
     
     
         60 . The pumpjack motor system of  claim 59 , wherein at least one of the predetermined load limits corresponds to structural integrity of the polish rod. 
     
     
         61 . The pumpjack motor system of  claim 59 , wherein at least one of the predetermined load limits corresponds to structural integrity of a gear box coupled to the motor and the polish rod. 
     
     
         62 . The pumpjack motor system of  claim 58 , wherein the local controller is operable to detect the detrimental operating condition by identifying an abrupt load spike based on the data structure. 
     
     
         63 . The pumpjack motor system of  claim 58 , wherein the data structure comprises a dynamometer surface card. 
     
     
         64 . The pumpjack motor system of  claim 58 , wherein the data structure comprises a downhole pump card. 
     
     
         65 . The pumpjack motor system of  claim 50 , wherein the local controller is operable to detect the detrimental operating condition by selecting a speed adjustment value to increase the target motor speed at a control period within the second pump stroke cycle preceding or subsequent to a different control period where the detrimental operating condition is likely to reoccur. 
     
     
         66 . The pumpjack motor system of  claim 50 , wherein the controller automatically adjusts one or more of the target motor speeds by selecting a speed adjustment value to decrease the target motor speed at a control period within the second pump stroke cycle where the detrimental operating condition is likely to reoccur. 
     
     
         67 . The pumpjack motor system of  claim 50 , wherein the controller determines the one or more speed adjustment values by selecting a speed adjustment value to decrease the target motor speed at a control period within the second pump stroke cycle preceding a different control period where the detrimental operating condition is likely to reoccur. 
     
     
         68 . The pumpjack motor system of  claim 50 , wherein the electric motor comprises a regenerative drive configured to provide a breaking torque to control the descent of a rod system of the pumpjack during a downstroke of each of the stroke cycles, while simultaneously converting kinetic energy of the rod system into electrical power. 
     
     
         69 . A method of pumping fluid, the method comprising:
 operating an electric motor of a pumpjack to pump fluid, according to a predetermined motor speed profile comprising a plurality of target motor speeds corresponding to each of a plurality of discrete pump stroke cycle segments, while receiving load data from one or more sensors mounted to monitor at least one operating condition of the pumpjack;   storing and updating a pump stroke cycle load profile based on the received load data over a period of several pump stroke cycles; and   in response to detecting load data deviating from the load profile by more than a predetermined deviation threshold, automatically decrementing a subset of the plurality of target motor speeds selected based on a position of the deviating load data within the stroke cycle.   
     
     
         70 . The method of  claim 69 , wherein the detected load data deviation is indicative of a rod load spike. 
     
     
         71 . The method of  claim 69 , wherein the detected load data deviation is indicative of a pump-off condition. 
     
     
         72 . The method of  claim 69 , wherein the detected load data deviation is indicative of a gearbox torque transfer anomaly. 
     
     
         73 . The method of  claim 69 , wherein at least one of the sensors comprises a load sensor. 
     
     
         74 . The method of  claim 73 , wherein the load sensor is responsive to load of a polish rod of the pumpjack. 
     
     
         75 . The method of  claim 69 , wherein at least one of the sensors comprises a crank rotation sensor. 
     
     
         76 . The method of  claim 69 , wherein at least one of the sensors comprises a motor shaft position sensor. 
     
     
         77 . The method of  claim 69 , wherein at least one of the sensors comprises a motor current sensor. 
     
     
         78 . The method of  claim 69 , wherein the pump stroke cycle load profile comprises a data structure relating position to load with respect to a polish rod of the pumpjack over one or more of the pump stroke cycles based on the sensory feedback. 
     
     
         79 . The method of  claim 78 , further comprising detecting the load data deviation by comparing the data structure to one or more predetermined load limits. 
     
     
         80 . The method of  claim 79 , wherein at least one of the predetermined load limits corresponds to structural integrity of the polish rod. 
     
     
         81 . The method of  claim 79 , wherein at least one of the predetermined load limits corresponds to structural integrity of a gear box coupled to the motor and the polish rod. 
     
     
         82 . The method of  claim 69 , wherein the electric motor comprises a regenerative drive, and wherein the method further comprises providing a breaking torque to control the descent of a rod system of the pumpjack during a downstroke of the pump stroke cycle, while simultaneously converting kinetic energy of the rod system into electrical power.