| 摘要 |
<p>An intermediate weight member (10) having a variable cross-section or bending moment of inertia as a function of member length is disclosed. At one end of the member (10) a slip and elevator section (14) is provided. A partially grooved section (16) of a diameter greater than that of the slip and elevator section extends between the slip and elevator section (24) and the other end of the member (10). The partially grooved section (16) includes two variable depth grooved sections (18, 20) separated by an ungrooved section (22). The ungrooved section (22) includes hardbanding rings (26, 28). The spiral grooves (30A, 30B, 30C) of variable depth grooved section (18, 20) vary in depth as a function of member length such that the bending moment of inertia varies as a function of length from the slip and elevator section (14) to the lower end of the member (10). Such variation changes from a constant bending moment of inertia at the slip and elevator section (14) to a substantially greater bending moment of inertia at the ungrooved section (22) and thence to a lower bending moment of inertia of a reduced diameter section (24) at its other end.</p> |
