Wellhead isolation tool and method of fracturing a well

1. A wellhead assembly comprising:

a casing;

a first tubular member extending above the casing;

a hanger within the first tubular member, the hanger comprising a first end opposite a second end and an annular wall extending there-between;

a second tubular member extending above the first tubular member and interfacing with said hanger annular wall;

a generally elongate annular member in the second tubular member, said annular member having a first end portion extending above a second end portion, wherein a seal is interposed between the second end portion of the elongate annular member and the hanger annular wall forming a seal between the second end portion of the elongate annular member and the hanger;

a flange extending from the second tubular member, wherein an axial load acting on the generally elongate annular member is reacted through said flange; and

a production tubular member aligned with the elongate annular member.

2. A wellhead assembly as recited in claim 1 wherein the seal is formed proximate the production tubular member.

3. A wellhead assembly as recited in claim 1 wherein the hanger comprises an inner surface, wherein the seal is interposed between the inner surface of the hanger and an outer surface of the second end portion of the elongate annular member.

4. A wellhead assembly as recited in claim 1 wherein said second tubular member interfaces with an inner surface of said hanger wall.

5. A wellhead assembly as recited in claim 4 further comprising another seal formed between the hanger and the first tubular member.

6. A wellhead assembly as recited in claim 5 wherein said another seal is formed by a seal interposed between the first tubular member and the hanger.

7. A wellhead assembly as recited in claim 5 wherein the first tubular member extends above the casing, the second tubular member extends above the first tubular member and the generally elongate annular member extends above the production tubular member.

8. A wellhead assembly as recited in claim 1 wherein the generally elongate annular member is a wellhead isolation tool.

9. A wellhead assembly as recited in claim 1 wherein the generally elongate annular member extends above the second tubular member.

10. A wellhead assembly comprising:

a casing;

a first tubular member extending above the casing;

a second tubular member extending above the first tubular member;

a third tubular member comprising a first end opposite a second end and an annular wall extending there-between, said annular wall comprising an annular inner surface, said annular wall interfacing with the second tubular member;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion above a second end portion, wherein the elongate annular member is a wellhead isolation tool;

a seal between the second end portion and the annular inner surface of the third tubular member annular wall;

another seal between the third tubular member and the first tubular member; and

a production tubular member aligned with the elongate annular member, wherein a first flange extends from the second tubular member and a second flange extends from the wellhead isolation tool, wherein the first and second flanges are fastened together.

11. A wellhead assembly as recited in claim 10 wherein said another seal is formed proximate the production tubular member.

12. A wellhead assembly as recited in claim 10 further comprising at least a fastener radially penetrating the first flange and engaging the wellhead isolation tool.

13. A wellhead assembly as recited in claim 10 wherein at least a portion of the second tubular member is sandwiched between the elongate annular member and the third tubular member.

14. A wellhead assembly as recited in claim 10 wherein the third tubular member is a hanger.

15. A wellhead assembly as recited in claim 10 wherein said second tubular member interfaces with the annular inner surface of said third tubular member wall.

16. A wellhead assembly comprising:

a casing;

a first tubular member extending above the casing;

a second tubular member extending above the first tubular member;

a third tubular member comprising a first end opposite a second end and an annular wall extending there-between, said annular wall comprising an annular inner surface, said annular wall interfacing with the second tubular member;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion above a second end portion, wherein the elongate annular member is a wellhead isolation tool;

a seal between the second end portion and the annular inner surface of the third tubular member annular wall;

another seal between the third tubular member and the first tubular member;

a flange extending from the second tubular member, wherein an axial load acting on the generally elongate annular member is reacted through said flange; and

a production tubular member aligned with the elongate annular member.

17. A wellhead assembly as recited in claim 11 wherein said second tubular member interfaces with the annular inner surface of said third tubular member wall.

18. A wellhead assembly comprising:

a casing;

a first tubular member extending above the casing;

a second tubular member extending above the first tubular member;

a third tubular member comprising a first end opposite a second end and an annular wall extending there-between, said annular wall comprising an annular inner surface, said annular wall interfacing with the second tubular member;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion above a second end portion, wherein the elongate annular member is a wellhead isolation tool;

a seal between the second end portion and the annular inner surface of the third tubular member annular wall;

another seal between the third tubular member and the first tubular member; and

a production tubular member aligned with the elongate annular member, wherein the second tubular member comprises a flange, wherein the assembly further comprises a fastener radially penetrating said flange and fastening said flange to the wellhead isolation tool.

19. A wellhead assembly as recited in claim 12 wherein said second tubular member interfaces with the annular inner surface of said third tubular member wall.

20. A wellhead assembly comprising:

a casing;

a first tubular member mounted over the casing;

a second tubular member over the first tubular member;

a flange extending from said second tubular member;

a third tubular member interfacing with the second tubular member;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion extending above a second end portion, wherein the elongate annular member is a wellhead isolation tool;

a radially extending fastener penetrating said flange and fastening said flange to the wellhead isolation tool;

a seal between the second end portion and the third tubular member; and

a production tubular member aligned with the elongate annular member.

21. The wellhead assembly as recited in claim 20 wherein the generally elongate annular member is a wellhead isolation tool.

22. A wellhead assembly comprising:

a casing;

a first tubular member mounted over the casing;

a second tubular member over the first tubular member;

a third tubular member comprising a wall defining an annulus, wherein said second tubular member interfaces with said wall;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion extending above a second end portion, wherein the elongate annular member interfaces with the second tubular member and interfaces with the third tubular member;

a seal between the second end portion and the third tubular member wall; and

a production tubular member aligned with the elongate annular member.

23. A wellhead assembly as recited in claim 22 wherein said second tubular member interfaces with an inner surface of said third tubular member wall.

24. A wellhead assembly comprising:

a casing;

a first tubular member mounted over the casing;

a second tubular member over the first tubular member;

a third tubular member comprising a wall defining an annulus interfacing with the second tubular member;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion above a second end portion;

a seal between the second end portion and an inner surface of the third tubular member annular wall;

another seal between the third tubular member and the first tubular member; and

a production tubular member aligned with the elongate annular member, wherein the elongate annular member is a wellhead isolation tool, wherein a first flange extends from the second tubular member and a second flange extends from the wellhead isolation tool, wherein the first and second flanges are fastened together, and wherein at least a fastener radially penetrates the first flange and engages the wellhead isolation tool.

25. A wellhead assembly comprising:

a casing;

a first tubular member mounted over the casing;

a second tubular member over the first tubular member;

a third tubular member comprising a wall defining an annulus interfacing with the second tubular member;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion above a second end portion;

a seal between the second end portion and an inner surface of the third tubular member annular wall;

another seal between the third tubular member and the first tubular member; and

a production tubular member aligned with the elongate annular member, wherein the elongate annular member is a wellhead isolation tool, and wherein the second tubular member comprises a flange, the assembly further comprising a fastener radially penetrating said flange and fastening said flange to the wellhead isolation tool.

26. A wellhead assembly comprising:

a casing;

a first tubular member mounted over the casing;

a second tubular member over the first tubular member;

a third tubular member comprising a wall defining an annulus interfacing with the second tubular member;

a generally elongate annular member at least partly within the second tubular member and at least partly within the third tubular member, said annular member having a first end portion above a second end portion;

a seal between the second end portion and an inner surface of the third tubular member annular wall;

another seal between the third tubular member and the first tubular member; and

a production tubular member aligned with the elongate annular member, wherein at least a portion of the second tubular member is sandwiched between the elongate annular member and the third tubular member.

27. A wellhead assembly as recited in claim 22 wherein the generally elongate annular member extends above the second tubular member.