EP0911482B1 - Stress relief joints for risers - Google Patents

Stress relief joints for risers Download PDF

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Publication number
EP0911482B1
EP0911482B1 EP19980308732 EP98308732A EP0911482B1 EP 0911482 B1 EP0911482 B1 EP 0911482B1 EP 19980308732 EP19980308732 EP 19980308732 EP 98308732 A EP98308732 A EP 98308732A EP 0911482 B1 EP0911482 B1 EP 0911482B1
Authority
EP
European Patent Office
Prior art keywords
riser
pipes
stress relief
pipe
relief joint
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19980308732
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0911482A3 (en
EP0911482A2 (en
Inventor
Lyle David Finn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Deep Oil Technology Inc
Original Assignee
Deep Oil Technology Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Deep Oil Technology Inc filed Critical Deep Oil Technology Inc
Publication of EP0911482A2 publication Critical patent/EP0911482A2/en
Publication of EP0911482A3 publication Critical patent/EP0911482A3/en
Application granted granted Critical
Publication of EP0911482B1 publication Critical patent/EP0911482B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/01—Risers
    • E21B17/017—Bend restrictors for limiting stress on risers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
    • B63B21/502—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers by means of tension legs

Definitions

  • This invention relates to stress relief joints for risers such as those used in the production of hydrocarbons offshore, and more particularly to such stress relief joints used for risers in conjunction with floating structures.
  • the lower ends of the tendons and risers are connected to the sea floor by means of additional pipes or risers embedded in and grouted to the sea floor.
  • the upper ends of the tendons and risers pass through openings in the keel or bottom portion of the vessels and are supported vertically by tension means located near the water surface.
  • US-A-4 854 781 discloses a variable rigidity element for protecting a riser near the sea floor, the element comprising a number of shells surrounding the riser, two or more concentric rings of shells being proposed.
  • a stress relief joint for use with a riser in floating systems wherein a vessel is subject to variable motion caused by wind, currents and/or wave action, the riser having one end connectable to the sea floor and an upper riser portion for passing through an opening at the bottom of the vessel, the stress relief joint comprising:
  • a preferred embodiment of the invention provides a stress relief joint for use with riser pipe in floating systems wherein a vessel is subject to variable motion caused by wind, current, and/or wave action.
  • the riser pipe has one end connectable to the sea floor and an upper portion arranged to pass through an opening at the bottom of the vessel.
  • the lower end which is connectable to other pipes at the sea floor, is provided with at least two concentric pipes or sleeves around the riser.
  • the lower ends of the pipes and riser are welded to a flange.
  • the upper end of each of the concentric pipes extends beyond the upper end of the pipe immediately surrounding it.
  • the annulus between the concentric pipes and the riser is preferably filled with a durable and pliable material. Also, shims may be inserted in the annulus at the end of each pipe segment.
  • Fig. 1 generally and schematically shows a vessel 20 of spar or tension buoyant tower type with a pipe 22 exiting from its bottom or keel 24 and having a suitable connection 26 to the sea floor 28. Lateral horizontal excursion of the vessel 20 is indicated by its position at 20'. Bending stresses occur on the pipe 22 where it exits the vessel at the keel 24 and at the sea floor connection 26, the dotted lines 22' exaggerating such bending.
  • FIG. 2 illustrates the preferred embodiment of the invention.
  • a stress relief joint 10 is generally comprised of sleeves or pipes 30, 32 and a flange 34.
  • the pipes 30, 32 are received around the riser 22 such that they are concentric with the riser 22.
  • the pipe 30 has an inner diameter larger than the outer diameter of the riser 22 such that an annulus is formed between the riser 22 and the first pipe 30.
  • the pipe 32 has an inner diameter larger than the outer diameter of the pipe 30 such that an annulus is formed between the pipes 30, 32.
  • the upper end of the pipe 30 extends beyond the upper end of the pipe 32 immediately surrounding it.
  • the annulus between the concentric pipes 30, 32 and the riser 22 is preferably filled with a durable and pliable material 36.
  • the pliable material 36 helps to insure that the riser 22 and the pipes 30, 32 all deflect laterally substantially the same amount.
  • a suitable material for the operating environment, such as cement grout, is used as the pliable material 36.
  • the lower ends of the pipes 30, 32 and riser 22 are welded to a flange 34.
  • Flange 34 is specially formed so as to effectively form short segments of the riser 22 and each pipe 30, 32, respectively indicated by numerals 22A, 30A, and 32A. Each segment extends upwardly from the base of the flange. This feature places the weld between the riser, pipes, and flange some distance away from the most severe fatigue location, where the riser and pipes meet the base of the flange. It can also be seen that the weld point of the riser 22 and each pipe 30, 32 to the flange 34 are spaced apart longitudinally. This allows the flange to be thicker at the base where needed for handling the loads occurring during normal conditions.
  • the lower end of the annulus formed between each segment 22A, 30A, and 32A may be provided with rounded smooth surface profiles as illustrated to reduce the stress concentration associated with sharp corners in the surface profile.
  • Shims 38 may be inserted in the annulus at the upper end of each pipe 30, 32 and rigidly held in place by any suitable means such as welding. Shims 38 may be formed of metal, such as steel, to provide durability and serve as retainers for less rigid materials 36, such as polyurethane.
  • the invention provides the advantage of lower costs because it may be formed from standard pipe sections that are readily available or can be manufactured using readily available equipment.
  • the design is more reliable than the very thick single pipe designs presently in use because it is easier to control the quality of the thinner pipe material.
  • the concentric pipe design also is more reliable because there is redundancy in the pipe sections.
  • the inner pipe normally has the highest hoop stresses since this pipe is required to contain internal and external pressures. However, with the invention, the bending stresses in the inner most pipe are significantly less than in the outer pipes. Thus, the inner most critical pipe is less likely to experience fatigue damage.

Landscapes

  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)
  • Direct Current Feeding And Distribution (AREA)
  • Mutual Connection Of Rods And Tubes (AREA)
EP19980308732 1997-10-27 1998-10-26 Stress relief joints for risers Expired - Lifetime EP0911482B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US95849597A 1997-10-27 1997-10-27
US958495 1997-10-27

Publications (3)

Publication Number Publication Date
EP0911482A2 EP0911482A2 (en) 1999-04-28
EP0911482A3 EP0911482A3 (en) 2002-04-03
EP0911482B1 true EP0911482B1 (en) 2004-10-20

Family

ID=25500995

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19980308732 Expired - Lifetime EP0911482B1 (en) 1997-10-27 1998-10-26 Stress relief joints for risers

Country Status (6)

Country Link
EP (1) EP0911482B1 (no)
AU (1) AU8950298A (no)
BR (1) BR9804215A (no)
FI (1) FI982309A (no)
NO (1) NO319687B1 (no)
OA (1) OA10906A (no)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2362183A (en) * 2000-05-10 2001-11-14 Secr Defence Method of reinforcing structures
BR0303446B1 (pt) * 2003-09-03 2014-04-08 Technip France Conjunto de fixação do enrijecedor para conjunto protetor de um tubo flexível contra desgaste por atrito
US7069958B2 (en) * 2004-01-29 2006-07-04 Wellstream International Limited Assembly and method for stiffening a flexible pipe
FR2930618B1 (fr) * 2008-04-24 2013-01-18 Saipem Sa Element de conduite de transition d'inertie pour encastrement d'une conduite rigide sous-marine
FR2930587A1 (fr) * 2008-04-24 2009-10-30 Saipem S A Sa Installation de liaison fond-surface d'une conduite rigide avec une conduite flexible a flottabilite positive et une piece de transition d'inertie
AU2014391862B2 (en) * 2014-04-25 2017-07-13 Nkt Hv Cables Ab Bend stiffener with bend indication
US9217300B1 (en) * 2014-11-21 2015-12-22 Technip France Subsea riser support and method for bridging escarpments
CN113883339A (zh) * 2021-09-29 2022-01-04 上海外高桥造船有限公司 一种海水提升管及其制造方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3605413A (en) * 1969-10-24 1971-09-20 North American Rockwell Riser with a rigidity varying lower portion
FR2397084A1 (fr) * 1977-07-06 1979-02-02 Inst Francais Du Petrole Embout de ligne flexible a raideur determinee variable
FR2616858B1 (fr) * 1987-06-18 1989-09-01 Inst Francais Du Petrole Element a raideur variable pour pied de colonne de transfert
US5683205A (en) * 1995-04-28 1997-11-04 Deep Oil Technology, Inc. Stress relieving joint for pipe and method
FR2760813B1 (fr) * 1997-03-14 1999-04-09 Coflexip Dispositif limiteur de courbure d'une conduite flexible

Also Published As

Publication number Publication date
BR9804215A (pt) 1999-12-28
OA10906A (en) 2001-10-11
FI982309A (fi) 1999-04-28
AU8950298A (en) 1999-05-13
NO984975L (no) 1999-04-28
NO319687B1 (no) 2005-09-05
FI982309A0 (fi) 1998-10-26
EP0911482A3 (en) 2002-04-03
EP0911482A2 (en) 1999-04-28
NO984975D0 (no) 1998-10-26

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