| 摘要 |
There is disclosed a bent sub comprising an outer tubular member connectible to the lower end of a drill string and an inner tubular member which is longitudinally reciprocable within the outer tubular member between retracted and extended positions. The inner member includes an upper tubular section which is sealably slidable within the outer tubular member, so that differential pressure urges the inner member toward its extended position, and a lower tubular section which is connected to the upper tubular section by a ball and socket joint to permit it to be swung between aligned and bent positions and connectible at its lower end above the upper end of a drilling motor. The lower section is held against rotation caused to move between aligned and bent positions as it is reciprocated with respect to the outer member.
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