Wireless Monitoring of Pump Jack Sucker Rod Loading and Position

Abstract

Forces on and respective positions of a pump jack sucker rod are determined in real time by load cells attached to the sucker rod and a position sensor, and are stored for further processing. A wireless transmitter transmits stored load and position values, calculated process parameters, and/or exception alerts to a wireless spread spectrum receiver that can be coupled to a motor speed controller used to set the rotational speed of the pump jack motor, and/or to monitoring systems, such as a central controller used to optimize total field production.

1 . A pump jack adapted for monitoring sucker rod load and position, comprising:
 a sucker rod string in a well bore pipe;   a polished rod coupled to the sucker rod string;   a horsehead coupled to the polished rod;   a rocker beam coupled to the horsehead;   a connecting rod coupled to the rocker beam;   a counter weight coupled to the connecting rod;   a pittman arm coupled to the connecting rod and counter weight;   a variable speed motor-gear drive assembly coupled to the pittman arm for rotational movement thereof;   a frame pivotally coupled to the rocker beam;   a base attached to the frame;   first and second force sensors attached to a proximate end of the sucker rod string, wherein the first and second force sensors measure elongation and compression stresses, respectively, of the sucker rod string while the sucker rod string moves up and down in the well bore pipe;   a position sensor attached toward the proximate end of the sucker rod string, wherein the position sensor determines positions of the sucker rod string;   a sensor interface assembly having wireless transmitting capabilities, wherein the sensor interface assembly is attached to the sucker rod string, and is coupled to the first and second force measurement sensors and the position sensor, whereby the sucker rod string forces and position information are wirelessly transmitted therefrom; and   a wireless receiver coupled to the variable speed motor-gear drive assembly, wherein the wireless receiver receives the force and position information transmitted from the interface assembly for determining control of rotational speed of the variable speed motor-gear drive assembly.   
     
     
         2 . The pump jack according to  claim 1 , wherein the position sensor is a tri-axial accelerometer. 
     
     
         3 . The pump jack according to  claim 1 , wherein the position sensor is a distance measuring device for measuring distances between the proximate end of the sucker rod string and a reference point. 
     
     
         4 . The pump jack according to  claim 3 , wherein the distance measuring device uses ultrasonic pulses for measuring the distances. 
     
     
         5 . The pump jack according to  claim 3 , wherein the distance measuring device uses radio frequency pulses for measuring the distances. 
     
     
         6 . The pump jack according to  claim 3 , wherein the distance measuring device uses infrared pulses for measuring the distances. 
     
     
         7 . The pump jack according to  claim 3 , wherein the distance measuring device uses laser light pulses for measuring the distances. 
     
     
         8 . The pump jack according to  claim 1 , further comprising a well bore pipe elongation distance sensor coupled to a proximate end of the well bore pipe, and from which elongation length of the well bore pipe is available as elongation data. 
     
     
         9 . The pump jack according to  claim 1 , further comprising pressure and flow rate sensors coupled to a flange/fluid takeoff assembly that is coupled to the proximate end of the well bore pipe, and from which pressure and flow rate at the flange/fluid takeoff assembly are available as pressure and flow rate data, respectively. 
     
     
         10 . An apparatus for monitoring position and load of a sucker rod in a pump jack, comprising:
 first and second force sensors attached at a proximate end of a sucker rod string of a pump jack, wherein the first and second force sensors measure elongation and compression stresses, respectively, of the sucker rod string while the sucker rod string moves up and down in a well bore pipe;   a position sensor attached toward the proximate end the sucker rod string, wherein the position sensor determines positions of the sucker rod string; and   a sensor interface assembly having wireless transmitting capabilities, wherein the sensor interface assembly is attached to the sucker rod string, and is coupled to the first and second force measurement sensors and the position sensor, whereby the sucker rod string forces and position information are wirelessly transmitted therefrom.   
     
     
         11 . The apparatus according to  claim 10 , wherein the position sensor is a distance measuring device for measuring distances between the proximate end of the sucker rod string and a reference point. 
     
     
         12 . The apparatus according to  claim 11 , wherein the distance measuring device uses ultrasonic pulses for measuring the distances. 
     
     
         13 . The apparatus according to  claim 11 , wherein the distance measuring device uses radio frequency pulses for measuring the distances. 
     
     
         14 . The apparatus according to  claim 11 , wherein the distance measuring device uses infrared pulses for measuring the distances. 
     
     
         15 . The apparatus according to  claim 11 , wherein the distance measuring device uses laser light pulses for measuring the distances. 
     
     
         16 . A pump jack adapted for monitoring sucker rod load and position, comprising:
 a sucker rod string in a well bore pipe;   a polished rod coupled to the sucker rod string;   a horsehead coupled to the polished rod;   a rocker beam coupled to the horsehead;   a connecting rod coupled to the rocker beam;   a counter weight coupled to the connecting rod;   a pittman arm coupled to the connecting rod and counter weight;   a variable speed motor-gear drive assembly coupled to the pittman arm for rotational movement thereof;   a frame pivotally coupled to the rocker beam;   a base attached to the frame;   first and second force sensors attached to a proximate end of the sucker rod string, wherein the first and second force sensors measure elongation and compression stresses, respectively, of the sucker rod string while the sucker rod string moves up and down in the well bore pipe;   a sensor interface assembly having wireless transmitting capabilities, wherein the sensor interface assembly is attached to the sucker rod string, and is coupled to the first and second force measurement sensors, whereby the sucker rod string force information is wirelessly transmitted therefrom;   a distance measuring device attached on a plan of the base and under the sensor interface assembly, wherein the position sensor determines positions of the sucker rod string by measuring distances between the distance measuring device and the sensor interface assembly; and   a wireless receiver coupled to the variable speed motor-gear drive assembly, wherein the wireless receiver receives the force information transmitted from the sensor interface assembly, and wherein position information from the distance measuring device is coupled to the variable speed motor-gear drive assembly, whereby control of rotational speed of the variable speed motor-gear drive assembly is determined from the force and position information.   
     
     
         17 . The pump jack according to  claim 16 , wherein the distance measuring device uses ultrasonic pulses for measuring the distances. 
     
     
         18 . The pump jack according to  claim 16 , wherein the distance measuring device uses radio frequency pulses for measuring the distances. 
     
     
         19 . The pump jack according to  claim 16 , wherein the distance measuring device uses infrared pulses for measuring the distances. 
     
     
         20 . The pump jack according to  claim 16 , wherein the distance measuring device uses laser light pulses for measuring the distances. 
     
     
         21 . The pump jack according to  claim 16 , further comprising a well bore pipe elongation distance sensor coupled to a proximate end of the well bore pipe, and from which elongation length of the well bore pipe is available as elongation data. 
     
     
         22 . The pump jack according to  claim 16 , further comprising pressure and flow rate sensors coupled to a flange/fluid takeoff assembly that is coupled to the proximate end of the well bore pipe, and from which pressure and flow rate at the flange/fluid takeoff assembly are available as pressure and flow rate data, respectively. 
     
     
         23 . An apparatus for monitoring position and load of a sucker rod in a pump jack, comprising:
 first and second force sensors attached at a proximate end of a sucker rod string of a pump jack, wherein the first and second force sensors measure elongation and compression stresses, respectively, of the sucker rod string while the sucker rod string moves up and down in a well bore pipe;   a sensor interface assembly having wireless transmitting capabilities, wherein the sensor interface assembly is attached to the sucker rod string, and is coupled to the first and second force measurement sensors, whereby the sucker rod string force information is wirelessly transmitted therefrom;   a distance measuring device attached on a plane of a base of the pump jack and under the sensor interface assembly, wherein the distance measuring device determines positions of the sucker rod string by measuring distances between the distance measuring device and the sensor interface assembly; and   a wireless receiver coupled to the variable speed motor-gear drive assembly, wherein the wireless receiver receives the force information transmitted from the sensor interface assembly, and wherein position information from the distance measuring device is coupled to the variable speed motor-gear drive assembly, whereby control of rotational speed of the variable speed motor-gear drive assembly is determined from the force and position information.   
     
     
         24 . The apparatus according to  claim 23 , wherein the distance measuring device uses ultrasonic pulses for measuring the distances. 
     
     
         25 . The apparatus according to  claim 23 , wherein the distance measuring device uses radio frequency pulses for measuring the distances. 
     
     
         26 . The apparatus according to  claim 23 , wherein the distance measuring device uses infrared pulses for measuring the distances. 
     
     
         27 . The apparatus according to  claim 23 , wherein the distance measuring device uses laser light pulses for measuring the distances.