Vibration Characteristics Study of Drill String Based on Rotary-impact Drilling Tool in Horizontal Well

To address the problems of large drilling friction and low rate of penetration (ROP) in the drilling process of horizontal well, the vibration characteristics research of drill string is conducted on the basis of rotaryimpact. The force analysis model of horizontal drill string is determined, and the dynamics differential equations are established to analyze the influence of key parameters. The vibration characteristics of different drill string nodes are studied, and then the performance parameters of rotaryimpact tool are obtained by experimental test with the combination of a new rotaryimpact drilling tool. The research results show that with the increase in stroke, weight on bit (WOB), impact deformation coefficient and effective contact area, the impact force can increase gradually. Moreover, maximum vibration displacement, velocity and frequency are in the installation position of rotaryimpact tool. The research conclusions can provide a theoretical reference for the structure optimization design and field application of the rotaryimpact tool, and they can also provide guidance for the dynamics study of horizontal drill string.