초록 ▼

Improved methods and apparatus are provided for sealing at the uppermost end of a casing string 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. A casing circulator is provided for l

Improved methods and apparatus are provided for sealing at the uppermost end of a casing string 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. A 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. An external sealing member of the casing circulator may be moved axially with respect to an inner packer tube, thereby allowing the sealing member to become inflated while also enabling fluid to pass through the casing circulator and into the casing string. The techniques of the present invention may also be used to fill the casing string as it is lowered into the well bore.

대표청구항 ▼

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 the casing string into the well bore, an uppermost end of the casing string extending above the rig floor to a position adjacent an elevator for g

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 the casing string into the 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 method comprising: providing a casing circulator having an exterior sealing member and an interior packer tube defining a fluid flow path; moving the casing circulator axially to a position within the uppermost end of the casing string; thereafter activating the casing circulator to seal the sealing member between the casing string and the interior packer tube; establishing fluid communciation between the interior of the packer tube and the interior of the casing string below the casing circulator sealing element while maintaining the sealing element in its sealed position; thereafter pumping fluid through the casing circulator and into the casing string to wash the well bore adjacent the lowermost end of the casing string; thereafter deactivating the casing circulator to unseal the sealing element from the casing string; and thereafter lowering the casing string into the well bore by lowering the elevator.