Calculation method of the build-up rate of the internal push point-the-bit rotary steering tool

The internal push point-the-bit rotary steering tool is a new type of dynamic point-the-bit rotary steerable sys-tem. This paper comprehensively uses the mechanical and trajectory method to calculate the build-up rate of the tool to evaluate its build-up ability and realize accurate control of the wellbore trajectory during the directional drilling process. The influence of tool structure, wellbore geometric parameters, drilling process parameters, bit-cutting anisotropy, and formation characteristics on the build-up ability are considered. The tool deflection force, the structural lateral force on the bit, and the formation deflection force were calculated respectively, and the calculation model for the build-up rate of the internal push point-the-bit rotary steering tool is established according to the relationship between force and cutting displacement. In order to study the variation of the build-up rate of the tool in different well slope sections under the conditions of fixed bottom hole assembly and formation parameters, the build-up rate simulation calculation was carried out. The calculation results show that the maximum build-up rate of the tool under stable and controlled conditions increases with the increase of the well inclination, which means the internal push point-the-bit rotary steering tool is suitable for extended reach wells and horizontal wells. The research results provide a theoretical basis for the design of bottom hole assembly and the optimization of drilling process parameters when using the internal push point-the-bit rotary steering tool for directional drilling.