초록 ▼

A wellhead isolation tool and a wellhead assembly incorporating such a tool are provided. The wellhead assembly has an annular assembly coupled to a well. The annular assembly may include a casing head coupled to the well and a tubing head mounted over the casing head. The wellhead isolation tool is

A wellhead isolation tool and a wellhead assembly incorporating such a tool are provided. The wellhead assembly has an annular assembly coupled to a well. The annular assembly may include a casing head coupled to the well and a tubing head mounted over the casing head. The wellhead isolation tool is suspended in the annular assembly. The wellhead isolation tool has a first end portion extending above the annular assembly and a second end portion below the first end portion within the annular assembly. A production casing suspended in the annular assembly and is aligned with the wellhead isolation tool.

대표청구항 ▼

1. A wellhead assembly comprising:a casing; a first tubular member mounted over the casing; a first tubular member flange extending from the first tubular member; a generally elongate annular member suspended in the first tubular member, said annular member having a first end portion extending above

1. A wellhead assembly comprising:a casing; a first tubular member mounted over the casing; a first tubular member flange extending from the first tubular member; a generally elongate annular member suspended in the first tubular member, said annular member having a first end portion extending above the first tubular member and a second end portion below the first end portion; a secondary flange extending from the elongate annular member; a plurality of fasteners fastening the secondary flange to the first tubular member flange; and a production tubular member aligned with the elongate annular member, wherein an axial force acts on the generally elongate annular member and is reacted in both the first tubular member flange and the secondary flange. 2. A wellhead assembly as recited in claim 1 wherein the first tubular member comprises an inner surface having an annular lip, wherein said annular lip extends between the elongate annular member second end portion and a portion of the production tubular member.3. A wellhead assembly as recited in claim 2 wherein said annular lip extends radially inward defining an opening having a first diameter, wherein the elongate annular member first end portion comprises an inner surface having a second diameter and wherein the portion of the production tubular member comprises an inner surface having a third diameter, wherein said first, second and third diameters are equal.4. A wellhead assembly as recited in claim 1 further comprising a seal between the elongate annular member second end portion and the first tubular member.5. A wellhead assembly as recited in claim 4 wherein the seal is between the elongate annular member second end portion and a first inner surface section of the first tubular member, wherein the first tubular member comprises a second inner surface section immediately above and concentric with the first inner surface section, said second inner surface section having a diameter greater than the first inner surface section.6. A wellhead assembly as recited in claim 4 further comprising a second seal between the elongate annular member second end portion and the first tubular member.7. A wellhead assembly as recited in claim 6 wherein the seals are self energizing seals.8. A wellhead assembly as recited in claim 6 further comprising a port through the first tubular member providing access to the elongate annular member at a location between the seals.9. A wellhead assembly as recited in claim 6 further comprising a passage through the elongate annular member providing access to an inner surface of the elongate annular member at a location between the seals from a remote location on the outer surface of the elongate annular member.10. A wellhead assembly as recited in claim 4 further comprising a fracturing tree mounted over the generally elongate annular member.11. A wellhead assembly as recited in claim 4 further comprising a BOP mounted over the generally elongate annular member.12. A wellhead assembly as recited in claim 4 wherein the secondary flange is separate from the elongate annular member.13. A wellhead assembly as recited in claim 12 further comprising:at least one lower depression formed on the elongate annular member outer surface; at least one upper depression formed on the elongate annular member outer surface above the lower depression; a first plurality lock screws each radially threaded through the first tubular member flange and engaging the at least one lower depression; and a second plurality of lock screws each radially threaded through the secondary flange and engaging the at least one upper depression, wherein the secondary flange is fastened to the first tubular member flange. 14. A wellhead assembly as recited in claim 13 wherein the elongate annular member comprises an outer surface portion between the first and second ends and below the at least one lower depression, said outer surface portion tapering from a larger diameter to a smaller diameter in a direction toward the second end, wherein the first tubular member comprises a tapering inner surface portion complementary to the inner tapering outer surface portion of the elongate annular member, and wherein the outer tapering surface portion of the elongate annular member seats against the tapering inner surface portion of the first tubular member.15. A wellhead assembly as recited in claim 14 further comprising a seal between the outer tapering surface portion of the elongate annular member and the tapering inner surface portion of the first tubular member.16. A wellhead assembly as recited in claim 12 further comprising a plurality lock screws each radially threaded through the first tubular member flange and engaging at least a depression formed on the elongate annular member outer surface, wherein the elongate annular member further comprises a threaded outer surface portion, and wherein the secondary flange is an annular, flange threaded on the elongate annular member threaded outer surface portion.17. A wellhead assembly as recited in claim 16 wherein the elongate annular member comprises an intermediate flange, and wherein the elongate annular member threaded outer surface portion is formed on the outer surface of the intermediate flange.18. A wellhead assembly as recited in claim 4 wherein the elongate annular member comprises an outer surface portion between the first and second ends, wherein the first tubular member comprises a tapering inner surface portion tapering from a larger diameter section to smaller diameter section in a direction toward the casing, wherein when suspended in the first tubular member, a portion of a section of the outer surface of the elongate annular member mates with the smaller diameter inner surface section of the first tubular member and a portion of the section of the outer surface of the elongate annular member is surrounded by the tapering inner surface portion of the first tubular member defining a gap between said tapering inner surface portion and said portion of the section of the outer surface of the elongate annular member surrounded by said tapering inner surface portion, and wherein said portion of the section of the outer surface of the elongate annular member is located below said first tubular member flange when said elongate annular member is suspended in said first tubular member flange.19. A wellhead assembly as recited in claim 4 further comprising:a plurality lock screws each radially threaded through the first tubular member flange and engaging at least a depression formed on the elongate annular member outer surface, wherein the elongate annular member flange is fastened to the first tubular member flange. 20. A wellhead assembly as recited in claim 1 wherein the elongate annular member comprises an outer surface portion between the first and second ends tapering form a larger diameter to a smaller diameter in a direction toward the second end, wherein the first tubular member comprises a tapering inner surface portion complementary to the inner tapering outer surface portion of the elongate annular member, and wherein the outer tapering surface portion of the elongate annular member seats against the tapering inner surface portion of the first tubular member.21. A wellhead assembly as recited in claim 20 further comprising a seal between the outer tapering surface portion of the elongate annular member and the tapering inner surface portion of the first tubular member.22. A wellhead assembly as recited in claim 1 wherein the elongate annular member comprises an outer surface portion between the first and second ends, wherein the first tubular member comprises a tapering inner surface portion tapering from a larger diameter section to smaller diameter section in a direction toward the casing, wherein when suspended in the first tubular member, a portion of a section of the outer surface of the elongate annular member mates with the smaller diameter inner surface section of the first tubular member and a portion of the section of the outer surface of the elongate annular member is surrounded by the tapering inner surface portion of the first tubular member defining a gap between said tapering inner surface portion and said portion of the section of the outer surface of the elongate annular member surrounded by said tapering inner surface portion.23. A wellhead assembly as recited in claim 1 wherein a portion of the first tubular member extends within a casing head coupled to the casing, the wellhead assembly further comprising:an annular hanger suspended in the first tubular member, wherein an annular gap is defined between an outer surface of the first tubular member and an inner surface of the casing head, wherein said annular hanger has a first inner surface section and a second inner surface section below the first inner surface section, wherein the second inner surface section has a diameter smaller than the first inner surface section, and wherein the second end portion of the elongate annular member extends to the first inner surface section of the annular hanger; a first annular groove formed on the outer surface of the hanger and aligned with a second annular groove formed on the inner surface of the first tubular member when the hanger is suspended in the first tubular member, wherein the annular gap extends to said aligned grooves; a spring loaded latch, wherein in cross-section the spring loaded latch comprises a first section extending opposite a second section and a third section extending from and transvesely to said first and second sections and fitted within the annular gap, wherein the latch can move from a first position where at least a portion of the first section of the latch is within the first annular groove and at least a portion of the second section of the latch is within the second annular groove to a second position where the first section of the latch is not within the first annular groove and at least a portion of the second section of the latch is within the second annular groove, wherein the latch is spring loaded to the second position; and a top nut having an first section, and a second section extending below the first section wherein the first section comprises an outer surface having a diameter greater than an outer surface of the top nut second section, and wherein the top nut is fitted within the annular gap causing the top nut second section to engage the third section of the spring latch and move the spring latch to the first position. 24. A wellhead assembly as recited in claim 23 wherein the top nut further comprises third section extending above the first section and surrounding the elongate annular member, said top nut third section having an end surface providing a landing for other wellhead equipment.25. A wellhead assembly as recited in claim 23 wherein the top nut first section is threaded on the outer surface of the hanger.26. A wellhead assembly as recited in claim 25 wherein the annular hanger is sandwiched between the top nut first section and the, elongate annular member.27. A wellhead assembly as recited in claim 23 further comprising a seal between the second end portion of the elongate annular member and the first inner surface section of the annular hanger.28. A wellhead assembly as recited in claim 1 wherein the first tubular member is a tubing head.29. A wellhead assembly as recited in claim 1 wherein an end of the elongate annular member is aligned with and faces an end of the production tubular member, wherein an inner surface diameter of said end of said elongate annular member is about equal to an inner surface diameter of said end of said production tubular member.30. A wellhead assembly as recited in claim 1 wherein the first tubular member flange and the secondary flange are fastened together.31. A wellhead assembly as recited in claim 1 further comprising:at least one lower depression formed on the elongate annular member outer surface; at least one upper depression formed on the elongate annular member outer surface above the lower depression; a first plurality lock screws each radially threaded through the first tubular member flange and engaging the at least one lower depression; and a second plurality of lock screws each radially threaded through the secondary flange and engaging the at least one upper depression and coupling the secondary flange to the generally elongate annular member, wherein the secondary flange is fastened to the first tubular member flange, and wherein the secondary flange is separate from the generally elongate annular member. 32. A wellhead assembly as recited in claim 1 further comprising a first plurality lock screws each radially threaded through one of said first tubular member flange and secondary flange and engaging the generally elongate annular member, wherein the other of said first tubular member flange and secondary flange is threaded on the generally elongate annular member, wherein the secondary flange is fastened to the first tubular member flange, and wherein the secondary flange is separate from the generally elongate annular member.33. A wellhead assembly as recited in claim 32 wherein the lock screws are threaded through the first tubular member flange and wherein the secondary flange is threaded on the generally elongate annular member.34. A wellhead assembly as recited in claim 1 further comprising a third flange extending from the generally elongate annular member spaced apart from the secondary flange.35. A wellhead assembly as recited in claim 1 wherein the generally elongate annular member second end is located within the first tubular member.36. A wellhead assembly as recited in claim 1 wherein the secondary flange is separate from the generally elongate member.37. A wellhead assembly comprising:a casing; a first tubular member mounted over the casing, the first tubular member comprising a flange and a tapering inner surface portion tapering from a larger diameter section to a smaller diameter section in a direction toward the casing; a generally elongate annular member suspended in the first tubular member, said annular member having a first end portion extending above the first tubular member and a second end portion below the first end portion within the first tubular member, wherein the elongate annular member comprises an outer surface portion between the first and second ends, wherein a portion of a section of the outer surface of the elongate annular member mates with the smaller diameter inner surface section of the first tubular member and a portion of the section of the outer surface of the elongate annular member is surrounded by the tapering inner surface portion of the first tubular member defining a gap between said tapering inner surface portion and said portion of the section of the outer surface of the elongate annular member surrounded by said tapering inner surface portion, and wherein said portion of the section of the outer surface of the elongate annular member is located below said first tubular member flange when said elongate annular member is suspended in said first tubular member flange; a second flange extending from the generally elongate annular member; and a production tubular member aligned with the elongate annular member, wherein an axial force acts on the generally elongate annular member and is reacted in both the first tubular member flange and the second flange. 38. A wellhead assembly as recited in claim 37 further comprising:a plurality lock screws each radially threaded through the first tubular member flange and engaging at least a depression formed on the elongate annular member outer surface, wherein the elongate annular member flange is fastened to the first tubular member flange. 39. A wellhead assembly as recited in claim 37 further comprising a seal between the elongate annular member second end portion and the first tubular member.40. A wellhead assembly as recited in claim 39 further comprising a second seal between the elongate annular member second end portion and the first tubular member.41. A wellhead assembly as recited in claim 40 wherein the seals are self energizing seals.42. A wellhead assembly as recited in claim 40 further comprising a port through the first tubular member providing access to the elongate annular member at a location between the seals.43. A wellhead assembly as recited in claim 40 further comprising a passage through the elongate annular member providing access to an inner surface of the elongate annular member at location between the seals from a remote location on the outer surface of the elongate annular member.44. A wellhead assembly as recited in claim 37 wherein the first tubular member is a tubing head.45. A wellhead assembly as recited in claim 37 wherein an end of the elongate annular member is aligned with and faces an end of the production tubular member, wherein an inner surface diameter of said end of said elongate annular member is about equal to an inner surface diameter of said end of said production tubular member.46. A wellhead assembly as recited in claim 37 wherein the first tubular member flange and the second flange are fastened together.47. A wellhead assembly as recited in claim 37 further comprising:at least one lower depression formed on the elongate annular member outer surface; at least one upper depression formed on the elongate annular member outer surface above the lower depression; a first plurality lock screws each radially threaded through the first tubular member flange and engaging the at least one lower depression; and a second plurality of lock screws each radially threaded through the second flange and engaging the at least one upper depression and coupling the secondary flange to the generally elongate annular member, wherein the second flange is fastened to the first tubular member flange, and wherein the second flange is separate from the generally elongate annular member. 48. A wellhead assembly as recited in claim 37 further comprising a first plurality lock screws each radially threaded through one of said first tubular member flange and second flange and engaging the generally elongate annular member, wherein the other of said first tubular member flange and second flange is threaded on the generally elongate annular member, wherein the second flange is fastened to the first tubular member flange, and wherein the second flange is separate from the generally elongate annular member.49. A wellhead assembly as recited in claim 48 wherein the lock screws are threaded through the first tubular member flange and wherein the second flange is threaded on the generally elongate annular member.50. A wellhead assembly as recited in claim 37 further comprising a third flange extending from the generally elongate annular member spaced apart from the second flange.51. A wellhead assembly as recited in claim 37 wherein the second flange is separate from the generally elongate annular member.52. A wellhead assembly comprising:a casing; a first tubular member mounted over the casing; a generally elongate annular member suspended in the first tubular member, said annular member having a first end portion extending above the first tubular member and a second end portion below the first end portion within the first tubular member; a production tubular member aligned with the elongate annular member; an annular nut coupled to the elongate annular member and surrounding an upper end of the first tubular member; a locking ring coupled to the first tubular member and surrounded by the annular nut; and a lock nut coupled to the annular nut at a location below the locking ring, wherein the lock nut has an inner surface having a diameter and wherein the locking ring has an outer surface having a diameter wherein the diameter of the of the lock nut inner surface is smaller than the diameter of the locking ring outer surface. 53. A wellhead assembly as recited in claim 52 further comprising a seal between the elongate annular member second end portion and the first tubular member.54. A wellhead assembly as recited in claim 53 wherein the elongate annular member comprises a flange and wherein the annular nut is threaded on the elongate annular member flange.55. A wellhead assembly as recited in claim 54 wherein an annular shoulder is formed on the elongate annular member flange accommodating an end portion of the first tubular member.56. A wellhead assembly as recited in claim 54 wherein the lock nut is threaded to the inner surface of the annular nut.57. A wellhead assembly as recited in claim 52 wherein the locking ring is a segmented ring having wickers on an inner surface interfacing with wickers formed on the first tubular member.58. A wellhead assembly as recited in claim 57 further comprising a plurality of push screws radially threaded though the annular nut and engaging the outer surface of the locking ring for urging the locking ring against the first tubular member.59. A wellhead assembly as recited in claim 52 wherein a portion of the first tubular member extends within a casing head coupled to the casing, the wellhead assembly further comprising:an annular hanger suspended in the casing head, wherein an annular gap is defined between an outer surface of the hanger and an inner surface of the casing head, wherein said annular hanger comprises an inner surface having an upper inner surface section, an intermediate inner surface section below the upper inner surface section and a lower inner surface section below the intermediate inner surface section, wherein the intermediate inner surface section has a diameter smaller than the upper inner surface section, and wherein the lower inner surface section has a diameter smaller than the intermediate inner surface section, wherein the first tubular member comprises a lower section within the upper inner surface section of the annular hanger and wherein the second end portion of the elongate annular member extends to the intermediate inner surface section of the annular hanger sandwiching a portion of the first tubular member lower section between the outer surface of the elongate annular member and the upper inner surface of the annular hanger; a first annular groove formed on the outer surface of the hanger and aligned with a second annular groove formed on the inner surface of the casing head when the hanger is suspended in the casing head, wherein the annular gap extends to said aligned grooves; a spring loaded latch, wherein in cross-section the spring loaded latch comprises a first section extending opposite a second section and a third section extending from and transvesely to said first and second sections and fitted within the annular gap, wherein the latch can move from a first position where at least a portion of the first section of the latch is within the first annular groove and at least a portion of the second section of the latch is within the second annular groove to a second position where the first section of the latch is not within the first annular groove and at least a portion of the second section of the latch is within the second annular groove, wherein the latch is spring loaded to the second position; and a top nut having an upper section and a lower section wherein the upper section comprises an outer surface having a diameter greater than an outer surface of the top nut lower section, and wherein the top nut is fitted within the annular gap causing the top nut lower section to engage the third section of the spring latch and move the spring latch to the first position. 60. A wellhead assembly as recited in claim 59 wherein the top nut upper section is threaded on the inner surface of casing head.61. A wellhead assembly as recited in claim 60 wherein annular hanger is sandwiched between the top nut upper section and the elongate annular member.62. A wellhead assembly as recited in claim 59 further comprising a seal between the elongate annular member second end portion and the intermediate inner surface section of the annular hanger.63. A wellhead assembly as recited in claim 62 further comprising:a second seal between the elongate annular member second end portion and the inner surface of the annular hanger; and an access path from an outer surface portion of the elongate annular member to an inner surface of the elongate annular member between the two seals. 64. A wellhead assembly as recited in claim 63 wherein the two seals are self energizing seals.65. A wellhead assembly as recited in claim 52 wherein the first tubular member is a tubing head.66. A wellhead assembly as recited in claim 52 wherein an end of the elongate annular member is aligned with and faces an end of the production tubular member, wherein an inner surface diameter of said end of said elongate annular member is about equal to an inner surface diameter of said end of said production tubular member.67. A wellhead assembly comprising:an annular head; a generally elongate annular member suspended in the head, said annular member having an upper end portion extending above the head and a lower end portion within the head; a production tubular member aligned with the elongate annular member; an annular nut coupled to the elongate annular member and surrounding an upper end of the head; a locking ring coupled to the head and surrounded by the annular nut; and a lock nut coupled to the annular nut at a location below the locking ring, wherein the lock nut has an inner surface having a diameter and wherein the locking ring has an outer surface having a diameter wherein the diameter of the of the lock nut inner surface is smaller than the diameter of the locking ring outer surface. 68. A wellhead assembly as recited in claim 67 further comprising:an annular hanger suspended in the head below the upper end of the head, wherein an annular gap is defined between an outer surface of the annular hanger and an inner surface of the head, wherein said annular hanger has an upper inner surface section and a lower inner surface section below the upper inner surface section, wherein the lower inner surface section has a diameter smaller than the upper inner surface section, and wherein the second end portion of the elongate annular member extends to the upper inner surface section of the annular hanger; a first annular groove formed on the outer surface of the hanger and aligned with a second annular groove formed on the inner surface of the head when the hanger is suspended in the head, wherein the annular gap extends to said aligned grooves; a spring loaded latch, wherein in cross-section the spring loaded latch comprises a first section extending opposite a second section and a third section extending from and transversely to said first and second sections and fitted within the annular gap, wherein the latch can move from a first position where at least a portion of the first section of the latch is within the first annular groove and at least a portion of the second section of the latch is within the second annular groove to a second position where the first section of the latch is not within the first annular groove and at least a portion of the second section of the latch is within the second annular groove, wherein the latch is spring loaded to the second position; and a top nut having an first section and a second section extending below the first section wherein the first section comprises an outer surface having a diameter greater than an outer surface of the top nut second section, and wherein the top nut is fitted within the annular gap causing the top nut second section to engage the third section of the spring latch and move the spring latch to the first position. 69. A wellhead assembly as recited in claim 68 wherein the top nut further comprises third section extending above the first section and surrounding the elongate annular member, said top nut third section having an end surface providing a landing for other wellhead equipment.70. A wellhead assembly as recited in claim 68 wherein the top nut first section is threaded on the outer surface of the hanger.71. A wellhead assembly as recited in claim 70 wherein at least a portion of the annular hanger is sandwiched between the top nut first section and the elongate annular member.72. A wellhead assembly as recited in claim 68 further comprising a seal between the second end portion of the elongate annular member and the annular hanger.73. A wellhead assembly as recited in claim 72 further comprising:a second seal between the elongate annular member second end portion and the annular hanger; and an access path from an outer surface portion of the elongate annular member to an inner surface of the elongate annular member between the two seals. 74. A wellhead assembly as recited in claim 73 wherein the two seals are self energizing seals.75. A wellhead assembly as recited in claim 67 wherein the head comprises a tubing head mounted over a casing head.76. A wellhead assembly as recited in claim 67 wherein an end of the elongate annular member is aligned with and faces an end of the production tubular member, wherein an inner surface diameter of said end of said elongate annular member is about equal to an inner surface diameter of said end of said production tubular member.77. A wellhead assembly comprising:wellhead member; a first tubular member mounted over the wellhead member; a first flange extending from the first tubular member; a generally elongate annular member suspended in the first tubular member; a second flange extending from the generally elongate annular member; a production tubular member aligned with the elongate annular member, wherein an end of the elongate annular member is aligned with the production tubular member, wherein an axial force acts on the generally elongate annular member and is reacted in both the first and second flanges; and a plurality lock screws each radially threaded through one of said first flange and second flange and engaging the generally elongate annular member, wherein the other of said first flange and second flange is threaded on the generally elongate annular member, wherein the second flange is fastened to the first flange, and wherein the second flange is separate from the generally elongate annular member. 78. A wellhead assembly as recited in claim 77 wherein the inner surface diameter of said end of said elongate annular member is equal to the inner surface diameter of said end of said production tubular member.79. A wellhead assembly as recited in claim 77 wherein the wellhead member is a casing head.80. A wellhead assembly as recited in claim 77 wherein the elongate annular member is a frac mandrel.81. A wellhead assembly as recited in claim 77 wherein the first and second flanges are fastened together.82. A wellhead assembly as recited in claim 77 further comprising a third flange extending from the generally elongate annular member spaced apart from the second flange.83. A wellhead assembly comprising:a casing; a first tubular member mounted over the casing; a first tubular member flange extending from the first tubular member; a generally elongate annular member suspended in the first tubular member, said annular member having a first end portion extending above the first tubular member and a second end portion below the first end portion within the first tubular member; a secondary flange extending from the elongate annular member; a plurality of fasteners fastening the secondary flange to the first tubular member flange; a production tubular member aligned with the elongate annular member; a first seal between the elongate annular member second end portion and the first tubular member; at least one lower depression formed on the elongate annular member outer surface; at least one upper depression formed on the elongate annular member outer surface above the lower depression; a first plurality lock screws each radially threaded through the first tubular member flange and engaging the at least one lower depression; a second plurality of lock screws each radially threaded through the secondary flange and engaging the at least one upper depression, wherein the secondary flange is fastened to the first tubular member flange, and wherein the secondary flange is separate from the elongate annular member; and a second seal between the outer tapering surface portion of the elongate annular member and the tapering inner surface portion of the first tubular member, wherein the elongate annular member comprises an outer surface portion between the first and second ends and below the at least one lower depression, said outer surface portion tapering from a larger diameter to a smaller diameter in a direction toward the second end, wherein the first tubular member comprises a tapering inner surface portion complementary to the inner tapering outer surface portion of the elongate annular member, and wherein the outer tapering surface portion of the elongate annular member seats against the tapering inner surface portion of the first tubular member. 84. A wellhead assembly comprising:a casing; a first tubular member mounted over the casing; a first tubular member flange extending from the first tubular member; a generally elongate annular member suspended in the first tubular member, said annular member having a first end portion extending above the first tubular member and a second end portion below the first end portion within the first tubular member, said elongate annular member further comprising a threaded outer surface portion; a secondary annular flange threaded on the elongate annular member threaded outer surface portion a secondary annular flange threaded on the elongate annular member threaded outer portion, wherein the secondary annular flange is separate from the elongate annular member; a plurality of fasteners fastening the secondary flange to the first tubular member flange; a production tubular member aligned with the elongate annular member; a seal between the elongate annular member second end portion and the first tubular member; and a plurality lock screws each radially threaded through the first tubular member flange and engaging at least a depression formed on the elongate annular member outer surface. 85. A wellhead assembly as recited in claim 84 wherein the elongate annular member comprises an intermediate flange, and wherein the elongate annular member threaded outer surface portion is formed on the outer surface of the intermediate flange.86. A wellhead assembly comprising:wellhead member; a first tubular member mounted over the wellhead member; a first flange extending from the first tubular member; a generally elongate annular member suspended in the first tubular member; a second flange extending from the generally elongate annular member; a production tubular member aligned with the elongate annular member, wherein an end of the elongate annular member is aligned with the production tubular member, wherein an axial force acts on the generally elongate annular member and is reacted in both the first and second flanges; at least one lower depression formed on the elongate annular member outer surface; at least one upper depression formed on the elongate annular member outer surface above the lower depression; a first plurality lock screws each radially threaded through the first flange and engaging the at least one lower depression; and a second plurality of lock screws each radially threaded through the second flange and engaging the at least one upper depression and coupling the secondary flange to the generally elongate annular member, wherein the second flange is fastened to the first flange, and wherein the second flange is separate from the generally elongate annular member. 87. A wellhead assembly as recited in claim 86 wherein the lock screws are threaded through the first flange and wherein the second flange is threaded on the generally elongate annular member.88. A wellhead assembly as recited in claim 86 further comprising a third flange extending from the generally elongate annular member spaced apart from the second flange.