US4480371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making insulated tubular conduit
Assignee: Nippon Steel Corp
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Filing: 1983-07-13
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Granted: 1984-11-06
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Expires: 2003-07-13
Abstract
Abstract A concentric insulating tubular conduit member for use in forming a conduit string, such as a tubing string in a subterranean well, is disclosed. Each individual concentric conduit comprises an outer tubing and an outwardly flared inner tubing welded to the outer tubing at the end of the flared section. The inner tubing member is formed from an initially straight cylindrical member having enlarged ends and, when outwardly flared, the flared ends, although stretched, have a thickness at least equal to the nominal thickness of the inner tubular member. Insulation may be contained within the annular cavity between the inner and outer tubing members and between inner and outer coupling members at the juncture between adjacent tubing sections.
Inventors
- 👤 David M. McStravick
- 👤 David V. Chenoweth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:08
CPC Classifications
F; F16; F16L; F16L59/00; F16L59/14; F16L59/15; E; E21; E21B; E21B17/00; E21B36/00; E21B36/003; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49428; Y10T29/49826; Y10T29/49879
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
97 words
A method of fabricating a concentric walled insulating tubular conduit for use in a subterranean well comprising the steps of: outwardly flaring the upset, enlarged ends of a tubular member initially having a nominal thickness intermediate the ends thereof and a greater thickness at the enlarged ends thereof by forging said ends using a swage having a mirror image profile; inserting the inner tubular member into an outer tubular member; and attaching said flared ends to said outer conduit to form a concentric walled tubular conduit having an annular cavity between the inner and outer tubular members.
Claim 2
Independent Claim
97 words
A method of fabricating a concentric walled insulating tubular conduit for use in a subterranean well comprising the steps of: outwardly flaring the upset, enlarged ends of a tubular member initially having a nominal thickness intermediate the ends thereof and a greater thickness at the enlarged ends thereof by forging said ends using a swage having a mirror image profile; inserting the inner tubular member into an outer tubular member; and attaching said flared ends to said outer conduit to form a concentric walled tubular conduit having an annular cavity between the inner and outer tubular members.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein said flared ends are attached to said outer tubular member by welding.
Claim 4
Dependent Claim
41 words
The method of claim 2 comprising the further step of prestressing the inner tubular member in tension after welding the first flared end to said outer tubular member and prior to welding the second flared end to said outer tubular member.
Claim 5
Independent Claim
79 words
A method of fabricating a concentric walled insulating tubular conduit for use in a subterranean well comprising the steps of: outwardly flaring at least one end of a first tubular member by forcibly inserting a swage into the end thereof to forge said end; inserting said first tubular through a second tubular member and attaching the ends thereof to said second conduit to form a concentric walled tubular conduit having an annular cavity between the first and second conduits.
Claim 6
Independent Claim
79 words
A method of fabricating a concentric walled insulating tubular conduit for use in a subterranean well comprising the steps of: outwardly flaring at least one end of a first tubular member by forcibly inserting a swage into the end thereof to forge said end; inserting said first tubular through a second tubular member and attaching the ends thereof to said second conduit to form a concentric walled tubular conduit having an annular cavity between the first and second conduits.
Claim 7
Dependent Claim
38 words
The method of claim 4 further comprising the step of prestressing said first tubular member in tension after attaching one end to said second tubular member and prior to attaching the other end to said second tubular member.
Claim 8
Independent Claim
18 words
The method of claims 4 or 5 wherein said flared end is welded to said second tubular member.
Claim 9
Dependent Claim
34 words
The method of claim 4 comprising the further step of attaching thermal insulation to the exterior of said first tubular member prior to insertion of said first tubular member into said second tubular member.
Claim 10
Dependent Claim
40 words
The method of claim 7 wherein structural load-bearing members are attached to the exterior of said first conduit prior to insertion into said second tubular member, said load-bearing members extending radially between said first and second tubular members upon insertion.
Claim 11
Independent Claim
201 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: flaring at least one end of a first tubular member, the one end of the first tubular member having been upset to increase the nominal thickness of the end in relation to the nominal thickness of the first tubular member intermediate the ends prior to flaring the upset end; inserting the first tubular member into a second tubular member; attaching one end of the inner tubular member to the outer tubular member; elongating the inner tubular member relative to the outer tubular member; attaching the second end of the inner tubular member to the outer tubular member, the attachment between a flared end of the inner tubular member to the outer tubular member being formed by welding the flared end to the outer tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular members, to minimize heat transfer therethrough.
Claim 12
Independent Claim
201 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: flaring at least one end of a first tubular member, the one end of the first tubular member having been upset to increase the nominal thickness of the end in relation to the nominal thickness of the first tubular member intermediate the ends prior to flaring the upset end; inserting the first tubular member into a second tubular member; attaching one end of the inner tubular member to the outer tubular member; elongating the inner tubular member relative to the outer tubular member; attaching the second end of the inner tubular member to the outer tubular member, the attachment between a flared end of the inner tubular member to the outer tubular member being formed by welding the flared end to the outer tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular members, to minimize heat transfer therethrough.
Claim 13
Independent Claim
155 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: inserting a first conventional oil well tubular member having upset ends with the nominal thickness of the ends of the tubular member being greater than the nominal thickness intermediate the ends thereof into a second conventional oil well tubular member having a larger diameter; welding a first end of the inner tubular member to the outer tubular member; elongating the inner tubular member relative to the outer tubular member; and welding the second end of the outer tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular members, to minimize heat transfer therethrough.
Claim 14
Independent Claim
155 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: inserting a first conventional oil well tubular member having upset ends with the nominal thickness of the ends of the tubular member being greater than the nominal thickness intermediate the ends thereof into a second conventional oil well tubular member having a larger diameter; welding a first end of the inner tubular member to the outer tubular member; elongating the inner tubular member relative to the outer tubular member; and welding the second end of the outer tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular members, to minimize heat transfer therethrough.
Claim 15
Dependent Claim
29 words
The method of claim 10 wherein the inner diameter of the outer tuublar member is larger than the outer diameter of the upset ends of the inner tubular member.
Claim 16
Independent Claim
200 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: inserting a first conventional oil well tubular member having upset ends with the nominal thickness of the ends of the tubular member being greater than the nominal thickness intermediate the ends thereof into a second conventional oil well tubular member having a larger diameter; welding a first end of the inner tubular member to the outer tubular member with the weld being on the upset end of the inner tubular member; elongating the inner tubular member relative to the outer tubular member; and welding the second end of the inner tubular member to the outer tubular member with the weld being on the upset end of the inner tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular members, being sealed by the welds on the upset ends of the inner tubular member to minimize heat transfer therethrough.
Claim 17
Independent Claim
200 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: inserting a first conventional oil well tubular member having upset ends with the nominal thickness of the ends of the tubular member being greater than the nominal thickness intermediate the ends thereof into a second conventional oil well tubular member having a larger diameter; welding a first end of the inner tubular member to the outer tubular member with the weld being on the upset end of the inner tubular member; elongating the inner tubular member relative to the outer tubular member; and welding the second end of the inner tubular member to the outer tubular member with the weld being on the upset end of the inner tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular members, being sealed by the welds on the upset ends of the inner tubular member to minimize heat transfer therethrough.
Claim 18
Independent Claim
233 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: flaring the ends of a first conventional oil well tubular member having upset ends with the nominal thickness of the ends of the tubular member being greater than the nominal thickness intermediate the ends thereof to increase the outer diameter of the ends of the first tubular member; inserting the first tubular member into a second conventional oil well tubular member having an inner diameter sufficient to receive the flared ends of the first tubular member; welding a first end of the inner tubular member to the first end of the outer tubular member along the flared end of the inner tubular member; elongating the inner tubular member relative to the outer tubular member; and welding the second end of the inner tubular member to the second end of the outer tubular member along the flared end of the inner tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular member, being sealed by the welds on the flared upset ends of the inner tubular member to minimize heat transfer therethrough.
Claim 19
Independent Claim
233 words
A method of fabricating a concentric walled insulating tubular conduit for transporting a heated fluid between the surface of the well and a subterranean location while minimizing the heat loss from the heated fluid during transport, comprising the steps of: flaring the ends of a first conventional oil well tubular member having upset ends with the nominal thickness of the ends of the tubular member being greater than the nominal thickness intermediate the ends thereof to increase the outer diameter of the ends of the first tubular member; inserting the first tubular member into a second conventional oil well tubular member having an inner diameter sufficient to receive the flared ends of the first tubular member; welding a first end of the inner tubular member to the first end of the outer tubular member along the flared end of the inner tubular member; elongating the inner tubular member relative to the outer tubular member; and welding the second end of the inner tubular member to the second end of the outer tubular member along the flared end of the inner tubular member, whereby the inner tubular member is prestressed in tension and the outer tubular member is prestressed in compression, with an annular insulating cavity defined, between the inner and outer tubular member, being sealed by the welds on the flared upset ends of the inner tubular member to minimize heat transfer therethrough.
Claim 20
Dependent Claim
52 words
The method of claim 13 wherein the flaring of the upset ends of the first tubular member is limited so that the final thickness of the enlarged upset ends is reduced during flaring but remains at least equal to the nominal thickness of the first tubular member intermediate the flared upset ends.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-06 | 1988-05-07 | 1988-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-06 | 1992-05-07 | 1992-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-06 | 1996-05-07 | 1996-11-06 | $7700.00 | Window Closed / Lapsed |