The spiral seam submerged arc welded steel pipe is rotated and drilled and begins to enter the soft formation. Under the action of the three-cone wheel, the drill bit first produces elastic shear deformation of the formation and then is removed under the pressure of the three-cone wheel. In the simulation environment, soft soil is a homogeneous clay, and the formation and cracks in the soil are not considered. Horizontal directional drilling is performed in abrupt formations that are in random dynamic contact with the roller cone bit. Friction occurs when the cone comes into contact with the formation. The impact force makes the spiral seam submerged arc welded steel pipe vibrate. When the tritone bit moves from soft to hard formations, it will inevitably produce large lateral vibrations and up-and-down vibrations.
When the drilling speed is 0.008m/s and the drill bit rotation speed is 2 rad/s, the pseudo strain energy curve during the advancement of the roller cone bit mainly includes viscosity and elasticity. However, since the viscous term usually dominates, most of the energy converted into pseudo-strain energy is irreversible. The deformation energy of spiral seam submerged arc welded steel pipe is the main energy consumed to control hourglass deformation. If the pseudo strain energy is too high, it means that the strain energy controlling the hourglass deformation is too large, and the mesh should be refined or modified. To reduce excessive pseudo-strain energy. The pseudo strain energy mutation in this model mainly occurs when the drill bit enters the soft soil layer and the roller cone bit passes through the abrupt formation interface. The greater the hardness of the formation, the greater the pseudo strain energy of the drill bit entering the formation. Simulate the drilling process of spiral welded pipe in sudden formation and predict the changes in drill bit drilling trajectory.
(1) Pseudo-strain energy mutations mainly occur when the drill bit enters the soft soil layer and when the roller cone bit passes through the abrupt formation interface. The higher the forming hardness, the greater the pseudo strain energy when the spiral seam submerged arc welded steel pipe enters forming.
(2) When drilling into a sudden formation, the spiral seam submerged arc welded steel pipe moves longitudinally and the drill bit vibrates. The harder the formation, the greater the bit vibration.
(3) Under certain formation inclination angle conditions, the greater the drilling speed of the drill bit, the greater the longitudinal deviation of the drilling trajectory; the greater the drill bit speed, the smaller the longitudinal deviation of the drilling trajectory. When the drill bit rotation speed is lower than 2.2rad/s, the impact of the rotation speed on the longitudinal deviation of the drilling trajectory is reduced.
(4) Under a certain drill bit speed, when the local formation inclination angle is 0° and 90°, there is no impact on the drilling trajectory; when the local inclination angle gradually increases, the longitudinal deviation of the drilling trajectory increases; when the local inclination angle exceeds 45°, the impact on the longitudinal deviation of the drilling track is reduced. The research results of this chapter are of great significance for improving the prediction accuracy of the drilling trajectory of tri-cone drill bits in steep formations and lay a theoretical foundation for correcting the drilling trajectory of spiral seam submerged arc welded steel pipes through horizontal pilot holes.
Post time: Sep-08-2023