Sucker-rod pumping units can be operated over a range of pumping speeds. It is expressed in Strokes per Minute (SPM). Obviously, this assumed that the up and down stroke of a unit forms one complete stroke cycle.
Sucker rod pumping speed can be calculated manually using a stopwatch or automatically by the mean of a pump-off controller (POC). This article will detail the manually pumping speed calculation procedure.
Manually Pumping Speed Calculation Procedure:
- Start the stopwatch at the bottom of the stroke and measure the time it takes for the unit to complete 10 strokes.
- Stop the stopwatch at the end of the 10 strokes when the PU is back at the bottom of the stroke. Make a note of the number of seconds it took.
- Convert the number of seconds into minutes (divide by 60).
- Divide 10 (the number of strokes) by the time in minutes to obtain the pumping speed expressed in strokes per minute (SPM).
Exercise: Calculate the pumping speed of this PU.
Time for 10 strokes: 98 seconds
Minutes: 98 sec / 60 = 1,63 minute
SPM = 10 strokes / 1,63 minutes = 6,13 strokes per minute