Lufkin Sucker Rod Pump Speed

[denniskb]

I need to determine the maximum rod lift speed of a sucker rod pump as a client has wells which trip on restart while pumping 100% liquid. I believe it may be the friction in the flowline when filled with liquid that is causing the trips. On normal operation they are fine as there is gas in the production.
I believe that the rod motion is probably sinusoidal and that I can find the velocity directly from the stroke and period i.e Max Velocity = Stroke / (2 x Period).
From this I will find the maximum flow as Max Flowrate = Max Velocity x Annulus Area.
I need to be very sure that I have determined the correct velocity and flowrate and would like to confirm my assumption that the motion is sinusoidal.
Are there any other known causes of re-start trips that I should check out? Dennis Kirk Engineering

http://www.ozemail.com.au/~denniskb

 

[denniskb]

I was too quick writing the original query.

The formula for rod velocity is found from
Angular Velocity = 2 x Pi / Period
and
Max Velocity = Angular Velocity x Stroke / 2
therefore
Max Velocity = Pi x Stroke / Period.

I now have information from Lufkin which confirms the movement is very close to sinusoidal.

Dennis Kirk Engineering

http://www.ozemail.com.au/~denniskb