| 摘要 |
<p>A drill string member comprising a body (1), and bearing races (5) around the circumference of the member. In certain embodiment, the presence of spherical bearings (25) on the surface of the member reduces radial torque and vertical drag to enable easier operation of the drill string. Advantages of one embodiment includes a reduction in the wear or breakages of the components used in drilling.</p> |
