| 摘要 |
<p>A sub (22) adapted for connection in a drill string between a first stabilizer (14) and a second stabilizer (16), which sub comprises an outer member (24) and an inner member (26) in telescoping relationship, an annular space (48) being formed between the members, with one member connectable to an upper portion of the drill string and the other member connectable to the lower portion of the drill string; protuberance means (46) on one of the members extending into the annular space between the members towards the adjacent surface of the other member; and receiving means (52) on the adjacent surface of the other member, adapted selectively to receive and engage said protuberance means such that the members are movable axially relative to one another, for substantially the whole of their telescoping stroke, when the protuberance means are disengaged from the receiving means, the receiving means being adapted to receive the protuberance means when the members are rotated relatively in one direction and to engage the protuberance means to prevent further relative rotation of the members in said one direction, thus allowing torque to be transmitted in said one direction whilst allowing only limited relative axial movement of the members enabling weight to be transmitted from one member to the other, the arrangement permitting the distance between the stabilizers to be adjusted without removing the drill string from the well bore.</p> |
