Vibration characteristics analysis and experimental study of new drilling oscillator

Abstract

In new drilling conditions such as extended reach drilling or long horizontal well, to avoid large friction between drill string and wellbore or weigh on bit decreasing, a new drilling vibration tool (called antifriction oscillator) is presented in this article. For discussing its working mechanism and performance, first, the kinematics models are established based on the structure design parameter, and then the horizontal vibration models are presented according to drilling conditions. With the numerical example results, it can be concluded that the frequency of the flow area between the static and dynamic valve plates is proportional to the flow rate. Moreover, with the increasing size of static valve plate, the flow area is increasing while the total axial force is decreasing. Furthermore, according to the experiment test results with static valve plate hole diameter 35.56 mm, the vibration results are discussed by comparing with numerical example results, and it can verify the analysis models’ rationality and the calculation formulas’ correctness. The research results provide basis for theoretical research and field applications of drilling oscillator. Furthermore, by changing corresponding parameters, the research methods and models can also provide reference for the design of new methods or tools of drilling friction reduction or rate of penetration increasing technologies.