Fig 1.
Borehole quality of push-the-bit RSS.
Fig 2.
Local mechanism diagram of Welleader system.
Fig 3.
The working principle of the Welleader system.
Fig 4.
The three-dimensional model of the steering rib.
Fig 5.
Force analysis of the system.
Fig 6.
Force analysis of a single rib.
Fig 7.
The three-dimensional model of the (a) circular arc front chamfer (b) polyline front chamfer (c) three well wall step model.
Fig 8.
Boundary condition.
Table 1.
Physical parameters for finite element analysis.
Fig 9.
The moment (a) Before touching the step (b) Touching the step (c) After touching the step (d) The enlarged diagram of Region 1.
Fig 10.
Stress nephogram of different models.
Fig 11.
Reaction force of different models cross (a) 1mm (b) 2mm (c) 3mm steps.
Fig 12.
Test block.
Fig 13.
a Test apparatus. b Schematic diagram of test.
Fig 14.
Test joint.
Fig 15.
The well wall step.
Fig 16.
The self-resetting displacement sensor.
Table 2.
Table of step height.
Fig 17.
Reaction force of two test blocks cross (a) 1mm (b) 2mm (c) 3mm steps.
Table 3.
Comparison of forward resistance.