Experiment Study Of The Drilling String Whirling Based On Drilling Mud Dynamic Lubrication

In oil drilling, the bottom drill string motion state is very complex, the lower compression drill string in the hole have two major states: forward whirl; backward whirl. Domestic and scholars have done a lot of research and analysis for the bottom drill string whirl mechanism, but still have some problems unsolved. Published by Li Zifeng, an article of “Inevitable way in drill-string whirling research: combination of drilling fluid power lubrication with drill string dynamics proposes a new theoretical research train of thought” does the detailed induction and summary for the research of drill string whirl theory and proposes a new theoretical research train of thought.This paper is based on the National Science Foundation “Based on the principle of minimum power consumption rate and the theory of drilling mud dynamic lubrication, theoretical and experimental research for drill string whirling(51374183)”, considered drilling mud dynamic lubrication, study the lower drill string through establishing the experimental device of simulating drill string whirling, and compared with the study of the foundation theory, provide theoretical basis for prevention drill string broken, make the drill string whirl theory has a qualitative leap. Indoor experimental simulation of drill string whirl is very few, so this paper has a certain innovation.Set up the drill string whirl experiment device considering drilling mud dynamic lubrication, after the reference of related experimental equipment. The device includes the control of motor speed system, loading system of axial force, drilling mud circulation and seepage control system, acquisition data system, the strain-resistor torque sensor and tilting device, centering device, etc.After the overall scheme is determined, mapped the mechanical drawing of drill string whirl experiment device and parts, assemble it finally. Debugging experiment, ensure each component matching, check the sensor measurement. Then change the experimental conditions and analyze the drilling mud dynamic lubrication and drill string compression buckling and whirl state, preliminarily get some drill string motion law.Experimental results show that the design of drill string simulation device is reasonable, meet the experimental requirements and the design intent, but at the same time have some shortage problem of design, therefore puts forward the concrete improvement opinions and subsequent experiment content and solution.