The natural frequencies of fiberglass sucker-rod strings can be calculated by treating the rod strings as modified spring/mass vibration systems. The ratio of the pumping-unit operating speed to the rod-string natural frequency can then be used as a basis for understanding fiberglass-rod-string performance and for predicting downhole pump stroke lengths.

Keywords:
resonance, stroke length, rod string, natural frequency, steel rod string, frequency, plunger stroke length, beam pumping, fluid load, upstroke
Subjects:
Artificial Lift Systems, Beam and related pumping techniques
Copyright 1988, Society of Petroleum Engineers
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