Key Parameters of Removing Blockage with Rotating Jets and Sand-Tubes

Whole-well circulation could not be built up for some oil and gas wells due to low pressure,and easy circulation loss and traditional blockage removing could not be used to clean these wells.In this paper,a novel technique was implemeneted,which involved a new plug removal technology,in which high pressure water through an oil tube rotates the nozzle,and rotating jets were formed to break up the blocking-mass.The broken blocking-mass would move up in water drive.When the leakage increased or pumping stopped,the blocking-mass would deposit in the sand-tube above the rotating nozzle and be brought to the ground with the sand-tube.A forced analysis of the blocking-mass was studied by solid-fluid mechanics,and the return flow rates with different silt styles were presented.The equation for calculating hydraulic parameter of rotating nozzle was derived by the moment balance theory.This plug removal technology was applied in Well Wo-51,and the blocking-mass of 9.98 meters was cleared in 15 min.It showed that the removing blockage with rotating jet and sand-tube turned out to be an effective blockage removing method for wells with low pressure and easy circulation loss.It would provide a novel means to plug removal.