Study on drill pipe erosion of gas carrying cuttings in gas drilling

Erosion of gas carrying cuttings in gas drilling is one of the causes of rapid drill pipe failure.Based on this,two phase flow model for drill pipe erosion of high-speed gas carrying cuttings is established by use of the computational fluid dynamics(CFD) method.Through the analysis of the annular gas flow field,the erosion rate of drill pipe surface,the erosion process and motion tracks of cuttings particles,some conclusions are drawn that some cuttings particles collided with drill pipe joints slope is contributed for erosion and the maximum erosion rate lies on the slope,the second worst erosion zone is the drill pipe surface up to the joint from 0.2 m to 1.8m in length.These areas may lead to serious erosion pits and micro-cracks.Ultimately,the crack propagation and failure phenomenon may also appear in the drilling process under combined action of tension,bend and torsion dynamic load.