Bellows type adjustable casing
AssigneeVetco Gray Inc.
InventorFrank C. Adamek
Life of this patent
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Abstract
A subsea assembly for producing fluids from a well having a casing string in the well supported with a hanger on an upper end. Cement is in a portion of an annulus between the casing string and walls of the well, thereby leaving segment of the casing string unsupported in the well. A motion compensating element is coaxially provided in the unsupported segment of the casing string to absorb axial expansion and/or contraction that may occur in the unsupported segment of the casing string.
Claims12
A subsea assembly for carrying fluids from a subsea wellbore comprising:
- an outer tubular inserted in an opening of the wellbore;
- a hanger mounted on a lower end of the outer tubular;
- a casing string depending from the hanger into the wellbore;
- and
- an axially expandable and compensating member provided along a portion of the casing string having a wall with undulations that comprise a series of slots along a length of the wall alternatingly formed about an inner circumference and about an outer circumference of the wall, each slot lying in a plane substantially perpendicular to an axis of the compensating member, the slots defining a series of cantilevers along a length of the body that are bendable when the body is axially compressed and that are bendable when the body is axially elongated, so that when casing above the compensating member is supported in tension the body transmits the tension to the casing below the compensating member.
A subsea assembly for carrying fluids from a subsea wellbore comprising:
- a wellhead assembly comprising a production tree mounted on a wellhead housing
- a hanger mounted within the wellhead housing;
- a casing string depending from the hanger into the wellbore;
- and
- a compensating member that is axially expandable and contractible provided along is portion of the casing string and having a body with a wall that includes undulations comprising a series of slots along a length of the wall alternatingly formed about an inner circumference and about an outer circumference of the wall, each slot lying in a plane substantially perpendicular to an axis of the compensating member, the slots defining a series of cantilevers along a length of the body that are bendable when the body is axially compressed and that are bendable when the body is axially elongated, so that when casing above the compensating member is supported in tension the body transmits the tension to the casing below the compensating member.
A compensating casing sub mechanically coupleable between a tubular member and a second member, comprising:
- a tubular body having a steel wall and an axis;
- a first end adapted to be affixed to an end of the tubular member;
- a second end adapted to be affixed to an end of the second member;
- a series of compressible segments integrally formed in the wall of the body circumscribing the axis and sequentially arranged along a length of the body to enable the body to be compressed between the tubular member and the second member to absorb thermal expansion of the tubular member;
- and wherein
- the compressible segments are defined by a series of helical slots along a length of the wall alternatingly formed about an inner circumference and about an outer circumference of the wall, each helical slot lying in a plane substantially perpendicular to an axis of the compensating member, the helical slots defining a series of cantilevers along a length of the body that are bendable when the body is axially compressed and bendable when the body is axially elongated.
Dependencies are inferred from the claim text.