US 4,340,245 AGranted

Insulated prestressed conduit string for heated fluids

AssigneeConoco Inc.

InventorJohn L. Stalder

Life of this patent

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Abstract

An improved prestressed conduit string for conducting heated fluids through a well bore comprised of a plurality of concentric double wall tube conduit sections each including an inner heated fluid conductor tube in tension prestress and a larger diameter outer tube in compression prestress to reduce heat transfer from the conducted fluids and prevent deformation of the conduit string when heated. By the present invention, the outer tubes of the conduit sections are shorter than the conductor tubes thereof whereby the ends of the conductor tubes extend short equal distances beyond the ends of the outer tubes. Connector means for connecting the conduit sections together in end-to-end relationship thereby forming the conduit string are comprised of annular resilient seal means positioned around axially aligned adjacent extending ends of the conductor tubes of adjacent conduit sections and coupling means positioned around the seal means and connected to the outer tubes of adjacent conduit sections thereby rigidly connecting the sections together and compressing the seal means against the sides of the adjacent extending ends of the conductor tubes and forming a sealed heat insulated joint between the conduit sections.

Claims10

Dependent claims

An improved prestressed conduit string for conducting heated fluids through a well bore, said conduit string being comprised of:

a plurality of connected-together conduit sections, each conduit section comprising:
an elongated large diameter outer tube positioned around a smaller diameter conductor tube, said outer tube being shorter than said conductor tube and being positioned with respect thereto whereby the ends of said conductor tube extend beyond the ends of said outer tube short equal distances;
and
bushing means positioned at the ends of said outer tube between said outer tube and said conductor tube, said bushing means being fixedly attached to said outer tube and to said conductor tube whereby said conductor tube is in tension prestress and said outer tube is in compression prestress;
said conduit sections being connected together in end-to-end relationship to thereby form said conduit string by connector means, each of said conductor means comprising:
annular resilient seal means positioned around axially aligned adjacent extending ends of said conductor tubes and between adjacent bushing means of adjacent conduit sections;
and
coupling means positioned around said seal means and connected to the outer tubes of said adjacent conduit sections thereby rigidly connecting said conduit sections together and compressing said seal means against the sides of said adjacent extending ends of said conductor tubes and between said bushing means of said conduit sections thereby forming a heat insulated sealed joint between said adjacent conduit sections.

5 more elements

In an insulated prestressed conduit string for conducting heated fluids through a well bore, said conduit string being comprised of a plurality of concentric double tube conduit sections each including an inner heated fluid conductor tube in tension prestress and a larger diameter outer tube in compression prestress, the improvement which comprises:

said outer tubes of said conduit sections being shorter than said conductor tubes thereof whereby the ends of said conductor tubes extend short equal distances beyond the ends of said outer tubes;
bushing means positioned at the ends of said outer tubes and fixedly attached to and between said conductor tubes and said outer tubes;
and
a plurality of connector means connecting said conduit sections together in end-to-end relationship thereby forming said conduit string, each of said connector means comprising:
annular resilient seal means positioned around axially aligned adjacent extending ends of said conductor tubes and between adjacent bushing means of adjacent conduit sections;
and
coupling means positioned around said seal means and connected to the outer tubes of said adjacent conduit sections thereby rigidly connecting said conduit sections together and compressing said seal means against the sides of said adjacent extending ends of said conductor tubes and between said bushing means of said adjacent conduit sections thereby forming a sealed heat insulated joint between said adjacent conduit sections.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/171,765Filed 24 Jul 1980
Granted: 20 Jul 1982
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

F16L 59/21
Arrangements specially adapted to local requirements at flanges, junctions, valves or the like: adapted for expansion-compensation devices
F16L 59/181
Adapted for joints: joints in which sealing surfaces are pressed together by means of a member, e.g. a swivel nut, screwed on or into one of the…
F24T 10/17
Using tube assemblies suitable for insertion into boreholes in the ground, e.g. geothermal probes: using tubes closed at one end, i.e. return-type…
Y02E 10/10
Energy generation through renewable energy sources: geothermal energy