Tubing rotator for a well

摘要

An improved tubing rotator is mounted to the casing bowl of a well, for rotating a tubing string extending down the well. A swivel dognut assembly is provided, comprising inner and outer sleeves. The tubing string is suspended from the inner sleeve which is rotatably supported from the stationary outer sleeve. The outer sleeve is adapted to be suspended from the tapered inner surface of the casing bowl, and is restrained from vertically upwards displacement by holddown screws. The outer sleeve is almost entirely contained or recessed within the casing bowl. A housing is bolted onto the casing flange. A pair of worms extend through the housing and driveably engage a ring gear associated with the inner sleeve. Because the sleeves are seated in the casing bowl, a compact rotator assembly is obtained. In addition, the tubing rotator is designed to permit the housing to be removed and a blowout preventer ("BOP") to be installed for well servicing while continuing to maintain a seal between the swivel dognut assembly and the casing bowl, thus sealing the annulus and preventing an otherwise possible blowout. The swivel dognut assembly can subsequently be removed with the tubing string through the BOP.