Vibration characteristics of the riser in underground water-sealing storage caverns

In this paper, the vibration characteristics of the riser in underground water-sealing storage caverns are analyzed and the influence of different supports on the vibration of the riser is studied. The following conclusions are made. First, the severe vibration of the riser during pump stopping is caused by the resonance occurred when the disturbance frequency from impeller rotation of the electric submersible pump driven by the inner flow coincides with the lower-order inherent frequency of the low-rigidity big-fall pipe. Second, the rigidity and inherent frequency of each order of the riser increase with the increasing of the number of fixed supports. Third, vibration of the riser can be suppressed by adjusting the number and positions of fixed supports in the shaft well, so as to make each lower-order inherent frequencies of the pipe not coincide with the disturbance frequency of the electric submersible pump during normal running and stopping.