Importance

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Abstract

Improved methods and apparatus are provided for inputting fluid into the uppermost end of a casing string gripped by an elevator supported from a traveling block by a pair of bails. The concepts of the present invention may be used to provide circulation from adjacent the lower end of the casing string and into a well bore to enable the casing string to be more easily lowered into the well bore, and may also be used to fill the casing string as it is lowered into the well bore. The casing circulator is provided for lowering into the uppermost end of the casing string above the rig floor, and for sealing with an interior surface of the uppermost end of the casing string. A support sub includes a hanger for suspending from the traveling block, and the casing circulator is supported from the support sub by a pup joint. The support sub is guided with respect to the bails by an adjustable alignment device, thereby ensuring that the circulator will be lowered into the casing string as the traveling blocks are lowered. Various techniques may be used to set the casing circulator, and an adjustment mechanism is provided to limit its upward travel when the casing string is pressurized.

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First Claim