Mechanical Modeling and Oblique Evaluation of a Full Rotation Steering Tool

Abstract

Directional rotary steerable is one of the key components of modern intelligent drilling, and the analysis of force and deformation in bottom hole assembly is the key to control a well trajectory. Although the introduction of edge calculation will significantly improve the case requirements in engineering application, due to the complexity of directional rotary steerable BHA, such as variable stiffness and discontinuity, few theoretical mechanical models can simultaneously solve the above problems and obtain accurate solutions. In this paper, the inclination angle and diameter of borehole are considered comprehensively. From weight on bit in drilling parameters, assembly structure parameters of multiple variable cross section, discontinuity, stabilizer diameter and position of all sorts of influencing factors, such as the vertical and horizontal bending method combined with the finite element method, a point-type rotary steering BHA is established as a new type of mechanical model, with actual project as an example, through iteration, and the calculated results with the software of numerical verify the correctness of the model. Finally, the model is used to study the bit side force of discontinuous directional rotatory stepping-type BHA, and the effects of offset, weight on bit, and distance between two stabilizers on bit side force are analyzed. The research results provide support for structure optimization and BHA parameter evaluation of directional rotary steerable tools.