| 摘要 |
A gravel pack safety sub selectively positionable in rotational or a non-rotational mode. The safety sub includes an adapter having lugs thereon and a mandrel having lugs thereon adjacent the adapter. A retainer attached to the adapter receives an end of the mandrel. The mandrel and retainer define an annular cavity therebetween, and a sleeve is positioned in the cavity. The sleeve has a hole therein which is nearer a first end thereof than a second end. The hole is alignable with an exterior recess in the mandrel and a shear pin positioned therethrough. The safety sub may be placed in a first position wherein the second end of the sleeve is adjacent the adapter and the lugs on the mandrel and adapter are separated. A bearing ring is positioned between the adapter and the mandrel for maintaining the separation of the lugs and providing a bearing surface therebetween. In a second position, the sleeve is reversed such that the first end thereof is adjacent the mandrel and the lugs are mutually engaged, thus preventing relative rotation between the adapter and mandrel. No bearing ring is used in the second position. If the bearing ring is removed from the apparatus when in the first position, the adapter and mandrel may be moved between the first and second positions.
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