US 5,191,939 A · Casing circulator and method

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.

Claims19

Dependent claims

An improved method of circulating fluid through a casing string and from a lowermost end of a casing string into a well bore for facilitating lowering of of the casing string into a well bore, an uppermost end of the casing string extending above the rig floor to a position adjacent an elevator for grasping the uppermost end of the casing string and moving the casing string axially with respect to the rig floor, the elevator being supported from bails extending from a traveling block of the rig, the method comprising:

providing a casing circulator having an exterior sealing member and an interior packer tube defining a flow path therein;
providing a casing circulator guide for engagement with the bails to guide the position of the casing circulator with respect to the uppermost end of the casing string as the traveling block is lowered;
supporting the casing circulator from the traveling block;
lowering the traveling block with respect to the uppermost end of the casing string such that the casing circulator will be positioned within the uppermost end of the casing string when the elevator is lowered about the uppermost end of the casing string;
thereafter setting the casing circulator to seal the sealing member between the casing string and interior packer tube;
thereafter pumping fluid through a flow line, through the flow path in the packer tube of the set casing circulator and into the casing string to wash the well bore adjacent the lowermost end of the casing string;
and
thereafter deactivating the casing circular to unseal the sealing element from the casing string.

5 more elements

An improved method of imputing drilling fluid into a casing string in a well bore so that the casing string may be lowered into the well bore, lowering of the casing string into a well bore controlled by regulating downward movement of a traveling block with respect to a rig floor, an uppermost end of the casing string extending above the rig floor to a position adjacent an elevator suspended by bails from the traveling block for selectively grasping the uppermost end of the casing string, the method comprising:

providing a circulator support sub having a flow path therein;
providing a casing circulator having an exterior sealing member and an interior packer tube defining a fluid flow path;
providing a circulator guide for engagement with the bails to guide the position of the casing circulator with the respect to the uppermost end of the casing string while lowering the traveling block, such that the casing circulator is automatically positioned within the uppermost end of the casing string when the elevator is positioned about the casing string:
suspending the circulator support sub from the traveling block;
suspending the casing circulator from the support sub;
securing the casing string in a fixed position with respect to the rig floor;
lowering the traveling block to a position such that the casing circulator is within the uppermost end of the casing string while the elevator is positioned about the casing string and the casing string is fixed with respect to the rig floor;
and
thereafter pumping the drilling fluid through the support sub, the casing circulator, and into the casing string.

6 more elements

Dependencies are inferred from the claim text.

Casing circulator and method

Life of this patent

Casing circulator and method

Life of this patent

Abstract

Claims19