초록 ▼

A wellhead assembly to seal to a production casing including one or more pressure-containing wellhead body members defining a vertical bore, with the lowermost of the wellhead body members sealing to the production casing. A fracturing isolation tool is sealed in the vertical bore of the wellhead bo

A wellhead assembly to seal to a production casing including one or more pressure-containing wellhead body members defining a vertical bore, with the lowermost of the wellhead body members sealing to the production casing. A fracturing isolation tool is sealed in the vertical bore of the wellhead body members above the production casing, and forms a pressure barrier profile in its internal bore. A removable protector sleeve is located at least partially within the fracturing isolation tool to seal, protect, isolate and cover the pressure barrier profile against a fracturing pressure and a fracturing fluid. After fracturing the protector sleeve is removed and a pressure barrier is sealed in the pressure barrier profile of the fracturing isolation tool. The invention also extends to the method of isolating the wellhead body members and to the fracturing isolation tool assembly which includes the fracturing isolation tool and the protector sleeve.

대표청구항 ▼

We claim: 1. A wellhead assembly which seals to a production casing, comprising: one or more pressure-containing wellhead body members defining a vertical bore extending there through, the lowermost end of the one or more wellhead body members being adapted to seal to the production casing; a fract

We claim: 1. A wellhead assembly which seals to a production casing, comprising: one or more pressure-containing wellhead body members defining a vertical bore extending there through, the lowermost end of the one or more wellhead body members being adapted to seal to the production casing; a fracturing isolation tool sealed in the vertical bore of the one or more wellhead body members above the production casing, and forming an internal bore extending vertically there through, a pressure barrier profile formed in the internal bore of the fracturing isolation tool to accommodate a pressure barrier; and a removable protector sleeve located at least partially within the fracturing isolation tool to seal, protect, isolate and cover the pressure barrier profile against a fracturing pressure and a fracturing fluid, the protector sleeve forming an internal bore extending vertically there through. 2. The wellhead assembly of claim 1, wherein: the one or more wellhead members comprise a tubing head and a tubing head adapter connected above the tubing head; the fracturing isolation tool seals in the vertical bore of the tubing head, and the protector sleeve seals in the vertical bore of the tubing head adapter; and the pressure barrier profile is formed in the fracturing isolation tool at a location to be within the tubing head when the fracturing isolation tool is sealed in the tubing head, such that when the fracturing isolation tool and the protector sleeve are sealed in the vertical bores, all seals and openings in and between the tubing head and the tubing head adapter are protected from the fracturing pressure and the fracturing fluid. 3. The wellhead assembly of claim 2, wherein the fracturing isolation tool and the protector sleeve are removable through the tubing head and tubing head adapter. 4. The wellhead assembly of claim 2, wherein the pressure barrier profile is formed with an interlocking surface to retain the pressure barrier and a sealing surface for the pressure barrier, and wherein the protector sleeve carries one or more circumferential seals to seal the pressure barrier profile in order to protect, isolate and cover the interlocking surface and the sealing surface of the pressure barrier profile. 5. The wellhead assembly of claim 4, wherein the protector sleeve carries two or more circumferential seals in order to seal above and below the interlocking surface and to seal either on, or above and below, the sealing surface of the pressure barrier profile. 6. The wellhead assembly of claim 5, wherein: the interlocking surface of the pressure barrier profile is a threaded surface to mate with threads on the pressure barrier; the sealing surface of the pressure barrier profile is located above and below the threaded surface; and the protector sleeve carries the two or more circumferential seals to seal on the sealing surface above and below the threaded surface. 7. The wellhead assembly of claim 5, wherein: the interlocking surface of the pressure barrier profile is formed with one or more circumferential grooves to mate with one or more shoulders or dogs carried on the pressure barrier; the sealing surface of the pressure barrier profile is located above or below the one or more circumferential grooves; and the protector sleeve carries the two or more circumferential seals to seal above and below the one or more circumferential grooves and to the sealing surface. 8. The wellhead assembly of claim 5, wherein the internal bore of the fracturing isolation tool has a diameter equal to or greater than the diameter of the production casing. 9. The wellhead assembly of claim 8, wherein the internal bore of the protector sleeve has a diameter equal to or greater than the diameter of the production casing. 10. The wellhead assembly of claim 5, wherein the fracturing isolation tool carries seals at its lower end to seal inside the production casing. 11. The wellhead assembly of claim 5, wherein the protector sleeve extends through the fracturing isolation tool and carries seals at its lower end to seal inside the production casing. 12. The wellhead assembly of claim 5, further comprising a seal bushing sealed within the vertical bore of the tubing head to seal to the lower end of the fracturing isolation tool and to the production casing. 13. The wellhead assembly of claim 5, further comprising a pressure barrier profile formed in the bore of the protector sleeve. 14. The wellhead assembly of claim 4, wherein the fracturing isolation tool and the protector sleeve are removable through the tubing head, the tubing head adapter and at least one wellhead member located thereabove. 15. The wellhead assembly of claim 1, further comprising a pressure barrier for sealing in the pressure barrier profile of the fracturing isolation tool when the protector sleeve is removed. 16. A fracturing isolation assembly for use in one or more pressure-containing wellhead body members which define a vertical bore extending there through, the lowermost end of the one or more wellhead body members being adapted to seal to a production casing, the fracturing isolation assembly comprising: a fracturing isolation tool adapted to seal in the vertical bore of the one or more wellhead body members above the production casing, and forming an internal bore extending vertically there through, a pressure barrier profile formed in the internal bore of the fracturing isolation tool to accommodate a pressure barrier; a removable protector sleeve located at least partially within the fracturing isolation tool to seal, protect, isolate and cover the pressure barrier profile against a fracturing pressure and a fracturing fluid, the protector sleeve forming an internal bore extending vertically there through. 17. The fracturing isolation assembly of claim 16, wherein: the one or more wellhead members comprise a tubing head and a tubing head adapter connected above the tubing head; the fracturing isolation tool seals in the vertical bore of the tubing head, and the protector sleeve seals in the vertical bore of the tubing head adapter; and the pressure barrier profile is formed in the fracturing isolation tool at a location to be within the tubing head when the fracturing isolation tool is sealed in the tubing head, such that when the fracturing isolation tool and the protector sleeve are sealed in the vertical bores, all seals and openings in and between the tubing head and the tubing head adapter are protected from the fracturing pressure and the fracturing fluid. 18. The fracturing isolation assembly of claim 17, further comprising a pressure barrier for sealing in the pressure barrier profile of the fracturing isolation tool when the protector sleeve is removed. 19. A method of isolating one or more wellhead members for fracturing, comprising: providing one or more pressure-containing wellhead body members defining a vertical bore extending there through to communicate with the production casing, the lowermost end of the one or more wellhead body members being adapted to seal to the production casing; locating a fracturing isolation tool in sealing relationship in the vertical bore of the one or more wellhead body members above the production casing, the fracturing isolation tool forming an internal bore extending vertically there through, and having a pressure barrier profile formed in the internal bore to accommodate a pressure barrier; locating a removable protector sleeve at least partially within the fracturing isolation tool to seal, protect, isolate and cover the pressure barrier profile against a fracturing pressure and a fracturing fluid, the protector sleeve forming an internal bore extending vertically there through; such that, when the fracturing isolation tool and the protector sleeve are sealed in the vertical bore, all seals and openings in the one or more wellhead body members are protected from a fracturing pressure and a fracturing fluid. 20. The method of claim 19, which further comprises: after fracturing, removing the protector sleeve; and locating a pressure barrier in sealing relationship in the pressure barrier profile of the fracturing isolation tool. 21. The method of claim 20, wherein: the one or more wellhead members are provided as a tubing head and a tubing head adapter mounted above the tubing head; the fracturing isolation tool is located to seal in the vertical bore of the tubing head, and the protector sleeve is located to seal in the vertical bore of the tubing head adapter; and the pressure barrier profile is formed in the fracturing isolation tool at a location within the tubing head; such that when the fracturing isolation tool and the protector sleeve are sealed in the vertical bore, all seals and openings in the tubing head and the tubing head adapter are protected from the fracturing pressure and the fracturing fluid.