Abstract
Downhole severe vibration of reamers while drilling is a critical bottleneck restricting drilling safety and efficiency. Existing studies often neglect the coupled effects of cutter dynamic wear on vibration and lack systematic quantitative analysis of the vibration suppression mechanisms of centralizers, resulting in a lack of reliable basis for anti-vibration design. This study innovatively establishes a dynamic model of the "equivalent upper drill string assembly + BHA" that incorporates cutter wear, and systematically reveals the synergistic vibration suppression mechanism of centralizer position, number, and outer diameter. The findings indicate that centralizer position serves as the foundation for vibration suppression: positioning it directly below the reamer provides optimal constraint, reducing the centroid offset area by 92.5%. Increasing the number of centralizers enhances vibration control, with a three-centralizer configuration reducing axial and torsional vibrations by 64.4% and 66.9%, respectively. Moreover, enlarging the centralizer outer diameter further amplifies the suppression effect: increasing the outer diameter from 204 to 214 mm results in additional reductions of 55.4% in axial and 31.6% in torsional vibrations. The proposed "position-number-outer diameter" synergistic design principle provides theoretical support and quantitative guidelines for vibration control in reamers while drilling, offering significant value for improving the reliability of drilling engineering.