Rotary drilling of spiral submerged arc welded steel pipes begins in soft strata. Under the action of the tricone cone, the drill bit first induces elastic shear deformation of the strata, which is then removed under the pressure of the tricone cone. In the simulated environment, the soft soil is homogeneous clay, and fissures in the strata and soil are not considered. Horizontal directional drilling is carried out in abruptly changed strata, with random dynamic contact between the strata and the tricone drill bit. Friction is generated when the cone contacts the strata. The impact force causes the spiral submerged arc welded steel pipe to vibrate. As the tricone drill bit moves from soft strata to hard strata, it inevitably generates significant lateral and vertical vibrations.
When the drilling speed is 0.008 m/s, and the drill bit rotation speed is 2 radians/s, the pseudo-strain energy curve during the tricone drill bit’s advance mainly includes viscosity and elasticity. However, since the viscous term usually dominates, most of the energy is irreversibly converted into pseudo-strain energy. The deformation energy of the spiral submerged arc welded steel pipe is the main energy consumed to control hourglass deformation. If the pseudo-strain energy is too high, it indicates 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 when the roller cone drill bit passes through the interface of the abrupt formation. The greater the formation hardness, the greater the pseudo-strain energy when the drill bit enters the formation. The drilling process of the spiral welded pipe in the abrupt formation is simulated to predict the change of the drill bit’s drilling trajectory.
(1) The pseudo-strain energy mutation mainly occurs when the drill bit enters the soft soil layer and when the roller cone drill bit passes through the interface of the abrupt formation. The higher the forming hardness, the greater the pseudo-strain energy when the spiral submerged arc welded steel pipe enters the forming layer.
(2) When drilling in the abrupt formation, the spiral submerged arc welded steel pipe moves longitudinally, and the drill bit vibrates. The greater the formation hardness, the greater the drill bit amplitude.
(3) Under certain formation dip angle conditions, the greater the drill bit speed, the greater the longitudinal deviation of the drilling trajectory; the greater the drill bit rotation speed, the smaller the longitudinal deviation of the drilling trajectory. When the drill bit speed is below 2.2 rad/s, the influence of the speed on the longitudinal deviation of the drilling trajectory decreases.
(4) At a certain drill bit speed, when the local formation dip angle is 0° and 90°, there is no effect on the drilling trajectory; when the local dip angle gradually increases, the longitudinal deviation of the drilling trajectory increases; when the local dip angle exceeds 45°, the influence on the longitudinal deviation of the drilling trajectory decreases.
Post time: Mar-05-2026