Short stroke piston pump

Abstract

A short stroke piston pump for recovering oil and/or water from marginal stripper wells, tar sands and coal beds includes a motor connected to one end of a drive rod, the motor capable of moving the drive rod in a generally up and down direction. A piston is connected to another end of the drive rod, the piston and drive rod are disposed in a riser pipe, the piston is adapted to transport fluid up the riser pipe as the piston moves up and down in the riser pipe. Additionally, a controller is communicatively connected to the motor, the controller changing speed and direction of the motor in response to a location or status of the drive rod within the riser pipe

1 . A method of extracting oil from marginal stripper wells comprising:
 providing a short stroke piston pump comprising:
 a motor connected to one end of a flexible drive rod, the motor capable of moving the flexible drive rod in a generally up and down direction; 
 a piston connected to another end of the flexible drive rod, the piston and the flexible drive rod being disposed in a riser pipe, the piston adapted to transport fluid up the riser pipe as the piston moves up and down in the riser pipe; 
 a controller communicatively connected to the motor, the controller changing speed and direction of the motor in response to a location or status of the flexible drive rod within the riser pipe; 
   installing the short stroke piston pump in a marginal stripper well;   adjusting the controller to set a speed of the motor based on an oil yield of the marginal stripper well.   
   
   
       2 . The method of  claim 1  further comprising adjusting the controller to pause the motor at a bottom of a downstroke of the flexible drive rod to compensate for drive rod float or stretch. 
   
   
       3 . The method of  claim 1  further comprising adjusting the controller to pause the motor at a top of an upstroke of the flexible drive rod to compensate for drive rod float or stretch. 
   
   
       4 . The method of  claim 1 , wherein the flexible drive rod is made of a fiberglass material. 
   
   
       5 . The method of  claim 1 , wherein the flexible drive rod is greater than approximately 1000 ft in length. 
   
   
       6 . The method of  claim 1 , further comprising adjusting the motor to produce an upstroke speed that is different from a downstroke speed. 
   
   
       7 . The method of  claim 1 , further comprising adjusting the motor speed between approximately 50 Hz and about approximately 10 Hz. 
   
   
       8 . The method of  claim 7 , wherein the motor speed is approximately 30 Hz. 
   
   
       9 . The method of  claim 1 , wherein the motor moves the drive rod between about 27 strokes per minute and about 5 strokes per minute. 
   
   
       10 . The method of  claim 1  further comprising determining the oil yield of the marginal stripper well. 
   
   
       11 . A short stroke piston pump comprising:
 a motor connected to one end of a flexible drive rod, the motor capable of moving the flexible drive rod in a generally up and down direction;   a piston connected to another end of the flexible drive rod, the piston and the flexible drive rod being disposed in a riser pipe, the piston adapted to transport fluid up the riser pipe as the piston moves up and down in the riser pipe;   a controller communicatively connected to the motor, the controller changing speed and direction of the motor in response to a location of the drive rod within the riser pipe.   
   
   
       12 . The short stroke piston pump of  claim 11 , wherein the controller pauses the motor at a bottom of a downstroke of the flexible drive rod to allow energy stored in the flexible drive rod to push the piston into a fluid in a well. 
   
   
       13 . The short stroke piston pump of  claim 11 , wherein the controller pauses the motor at a top of an upstroke of the flexible drive rod to allow energy stored in the flexible drive rod to release. 
   
   
       14 . The short stroke piston pump of  claim 11 , wherein the flexible drive rod is made of a fiberglass material. 
   
   
       15 . The short stroke piston pump of  claim 11 , wherein the flexible drive rod is greater than about 1000 feet in length. 
   
   
       16 . The short stroke piston pump of  claim 11 , wherein a flexible drive rod stroke length is between approximately 10 inches and approximately 30 inches. 
   
   
       17 . The short stroke piston pump of  claim 11 , wherein less than 10 barrels per week of oil are removed from a well. 
   
   
       18 . The short stroke piston pump of  claim 11 , wherein the controller adjusts the speed of the motor between approximately 50 Hz and approximately 10 Hz. 
   
   
       19 . The short stroke piston pump of  claim 18 , wherein the controller adjusts the speed of the motor to approximately 30 Hz. 
   
   
       20 . The short stroke piston pump of  claim 11 , wherein the controller adjusts the motor to produce a flexible drive rod stroke frequency in the range of about 27 strokes per minute to about 5 strokes per minute. 
   
   
       21 . The short stroke piston pump of  claim 11 , wherein the controller adjusts a speed at which the flexible drive rod is actuated. 
   
   
       22 . The short stroke piston pump of  claim 21 , wherein the controller sets an upstroke speed of the flexible drive rod different from a downstroke speed of the flexible drive rod. 
   
   
       23 . The short stroke piston pump of  claim 11 , wherein the controller adjusts motor speed based on a liquid yield of a well. 
   
   
       24 . The short stroke piston pump of  claim 11 , wherein the motor is electric. 
   
   
       25 . The short stroke piston pump of  claim 11 , wherein the motor is pneumatic. 
   
   
       26 . The short stroke piston pump of  claim 11 , wherein the controller can be remotely adjusted. 
   
   
       27 . The short stroke piston pump of  claim 11 , wherein the short stroke piston pump pumps oil from a marginal stripper well. 
   
   
       28 . The short stroke piston pump of  claim 11 , wherein the short stroke piston pump pumps heated bitumen from a tar sands well. 
   
   
       29 . The short stroke piston pump of  claim 11 , further including a ball screw connected to the motor and the flexible riser pipe, wherein one revolution of the ball screw raises the piston one inch. 
   
   
       30 . The short stroke piston pump of  claim 11 , further including a ball screw connected to the motor and the flexible riser pipe, wherein two revolutions of the ball screw raises the piston one inch. 
   
   
       31 . The short stroke piston pump of  claim 11 , wherein the short stroke piston pump pumps water from coal beds during methane dewatering operations.