The study is one of the bases to effectively enhance the rate of penetration (ROP) and control well deviation. Considering the complex stresses at the bottom hole, the stress field of the bottom hole was analyzed, and the physical model of the rock-cutter interaction was established. Then using finite element methods (FEM), a two-dimensional (2D) model of the rock-cutter interaction was established. The expressions for shear stress and normal stress of the failure plane of rock at the bottom hole, which contain formation pore pressure, were obtained. The real pore pressure at the bottom hole, which is not the original pore pressure for rock permeability and porosity, is related to time and location, and its distribution law can be expressed by the one-dimensional unstable filtration theory. It was found that with the weight on bit (WOB) increases, the effective stress on the cutter tip increased and the penetration depth of the cutter increased. With the differential pressure at the bottom hole increased, the penetration depth of the cutter decreased. When the overburden pressure increased, the penetration depth of the cutter decreased.
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