Dynamic Modeling and Operational Parameter Optimization of a Bidirectional Eccentric Reaming Tool in the While-Drilling Reaming Process

Eccentric reaming tools are widely integrated into bottom-hole assemblies during while-drilling reaming operations to improve borehole quality and enhance drilling-assembly passability. However, their eccentric geometry introduces periodic tool–borehole contact, friction, and impact excitations, which may adversely affect the dynamic stability of the drilling system. In this study, a process-oriented finite element dynamic model of a bottom-hole assembly incorporating a bidirectional eccentric reaming tool was developed to investigate coupled radial, axial, and torsional vibration responses under different stabilizer configurations. Three configurations, namely the near-bit, single-stabilizer, and double-stabilizer configurations, were systematically compared. The results indicate that the double-stabilizer configuration produces the most continuous and regular annular borehole profile and promotes a more stable tool–borehole contact state. Compared with the other configurations, it provides stronger lateral constraint, yields the lowest radial-displacement fluctuations, reduces radial and axial acceleration responses, and mitigates longitudinal impacts. The near-bit configuration exhibits the most pronounced torsional instability, including transient reverse rotation of the reaming tool, whereas no reverse rotation occurs under the double-stabilizer configuration. An orthogonal design was further conducted to optimize the operating parameters. Range analysis shows that rotational speed has a greater influence on the radial-displacement root-mean-square value than weight on bit within the investigated parameter range. The optimal operating condition was identified as a rotational speed of 50 rpm and a weight on bit of 80 kN. These findings demonstrate that bilateral stabilizer support can improve borehole regularity, suppress coupled vibration, and enhance the operational stability of while-drilling eccentric reaming systems.