WO2020096458A1 - Ombilicaux d'alimentation pour déploiement sous-marin - Google Patents

Ombilicaux d'alimentation pour déploiement sous-marin Download PDF

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Publication number
WO2020096458A1
WO2020096458A1 PCT/NO2019/050191 NO2019050191W WO2020096458A1 WO 2020096458 A1 WO2020096458 A1 WO 2020096458A1 NO 2019050191 W NO2019050191 W NO 2019050191W WO 2020096458 A1 WO2020096458 A1 WO 2020096458A1
Authority
WO
WIPO (PCT)
Prior art keywords
power
tubing
umbilical
integrated power
zinc coating
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.)
Ceased
Application number
PCT/NO2019/050191
Other languages
English (en)
Inventor
Sven Morten Hesjevik
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.)
Equinor Energy AS
Original Assignee
Equinor Energy AS
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 Equinor Energy AS filed Critical Equinor Energy AS
Publication of WO2020096458A1 publication Critical patent/WO2020096458A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/28—Protection against damage caused by moisture, corrosion, chemical attack or weather
    • H01B7/2806—Protection against damage caused by corrosion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/0072—Electrical cables comprising fluid supply conductors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/14—Submarine cables
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/18—Protection against damage caused by wear, mechanical force or pressure; Sheaths; Armouring
    • H01B7/22—Metal wires or tapes, e.g. made of steel
    • H01B7/221—Longitudinally placed metal wires or tapes
    • H01B7/225—Longitudinally placed metal wires or tapes forming part of an outer sheath
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/04—Flexible cables, conductors, or cords, e.g. trailing cables
    • H01B7/046—Flexible cables, conductors, or cords, e.g. trailing cables attached to objects sunk in bore holes, e.g. well drilling means, well pumps

Definitions

  • the invention relates to power umbilicals for subsea deployment, and in particular power umbilicals having improved corrosion protection.
  • Corrosion in steel components immersed in water is a well-known problem.
  • cathodic protection has been used to prevent corrosion. This is achieved by electrically coupling the steel component to a sacrificial piece of metal (e.g. aluminium) having a lower electrochemical potential.
  • the sacrificial piece of metal supplies electrons to the steel component, which prevents it from corroding.
  • An integrated power umbilical is designed to serve a specific piece of equipment, such as an oil well, and to supply it with power and other services such as telecommunication and fluids.
  • the umbilical consists of power cables as well as tubing containing various types of fluids.
  • the tubing is often made from corrosion resistant alloys, such as Super Duplex Stainless Steel (SDSS).
  • SDSS Super Duplex Stainless Steel
  • This biofilm causes a catalytic effect on the cathode reaction, leading to more noble electrochemical potential on the steel which increases the risk of crevice and pitting corrosion. It is therefore common to extrude a polymeric sheet over the tubing to provide a coating that prevents water from accessing the underlying steel.
  • Figure 1 is a schematic diagram of a cross section of an integrated power umbilical according to an embodiment
  • Figure 2 is a flow diagram illustrating the steps of a method of manufacturing an integrated power umbilical according to an embodiment.
  • a power umbilical provides electric power to consumers, often located subsea. Electric power consumers can be pumps, turbines or other equipment.
  • An integrated power umbilical having an SDSS tubing covered by a polymeric sheet can provide good corrosion protection.
  • the polymeric sheet may be damaged in small areas (e.g. scuffs and bending cracks). Such coating damage is not a problem for most systems, but can be surprisingly detrimental to an integrated power umbilical supplying AC power under water.
  • Recent experiments have shown that coating damage can lead to AC corrosion in an integrated power umbilical.
  • the polymeric sheet being an insulating material, causes a build-up of induced AC voltage in the steel tubing. The resulting current in an area where the coating is damaged causes high AC corrosion rates. Without the polymeric sheet, build-up of induced AC voltage does not occur, but then pitting and crevice corrosion becomes a problem caused by the elevated temperatures from the power cable.
  • FIG. 1 shows a schematic diagram of an embodiment of an integrated power umbilical 2, which addresses at least some of the problems outlined above.
  • the umbilical 2 comprises three power cords 4 for supplying AC power to a subsea component (not shown).
  • the power cords 4 are enclosed by an outer steel armour layer 6.
  • the outer layer 6 is covered by an outer plastic sheet 8.
  • metal tubing 10 (three tubes shown), preferably comprising a corrosion resistant metal such as SDSS.
  • the tubing 10 is covered by a zinc coating 12 (e.g. 200 gm to 300 gm in thickness), which provides an unbroken continuous cover over the tubing 10.
  • the umbilical 2 has been deployed and sea water 14 surrounds the power cords 4 and the tubing 10 in the voids.
  • the zinc coating 12 may prevent water from accessing the tubing 10, like a polymeric sheet would have, and thereby prevent corrosion in the tubing 10.
  • a polymeric sheet because of the electric conductive properties of zinc, there is no build up of induced AC voltage in the tubing 10. Hence, even if the zinc coating 12 is damaged, this does not cause high AC corrosion rates in the damaged area of the tubing 10.
  • the zinc coating 12 having a lower noble electrochemical potential than the tubing 10, also provides cathodic protection. More importantly, zinc acts as a weak biocide in water 14 and will prevent formation of a biofilm on the surface of the tubing 10 at elevated temperatures. Exposed to sea water, the zinc will corrode and it is not expected that the zinc coating 12 will be intact on the tubing surface throughout the design life of the umbilical 2. However, release of zinc ions into the confined water phase (i.e. the sea water that penetrates into the voids of the umbilical when immersed) will prevent the formation of a biofilm and hinder potential ennoblement which could lead to pitting and crevice corrosion.
  • the umbilical 2 would normally also comprise further conduits, for example, to supply water or other fluids.
  • the zinc coating 12 is applied in a thermal spraying process to achieve an adequate (unbroken) coverage and a desired thickness.
  • the coating has a thickness in the range of 200 pm to 1 mm, or preferably a thickness in the range of 200 pm to 300 pm.
  • a thicker coating 8 may provide a longer lifetime, but if the coating 8 is too thick, then bending cracks are more likely to occur. This may not be an important consideration for a fixed and rigid system, but may be important for an integrated power umbilical, which has some mechanical flexibility.
  • FIG 2 shows a flow diagram which illustrates the steps of a method of manufacturing an integrated power umbilical according to an embodiment.
  • the method comprises: providing one or more power cords for supplying AC power (step S1 ), providing a metal tubing adjacent to said power cord(s) (step S2), and applying a zinc coating to an outer surface of said tubing (step S3).
  • the step (S3) of applying the zinc coating may comprise thermally spraying zinc onto the tubing.
  • the thermal spray is used to apply a zinc coating with a submillimetre thickness, e.g. in the range of 200 pm to 300 pm.
  • the illustrated method may be used to manufacture an integrated power umbilical as shown in Figure 1.
  • the metal tubing is provided before the one or more power cords.
  • the invention may be defined as an integrated power umbilical for subsea deployment, comprising one or more power cords for supplying AC power, a metal tubing adjacent to said power cord(s), and a zinc coating covering an outer surface of said tubing.
  • embodiments of the invention can enable the use of subsea integrated power umbilicals without the risk of AC corrosion, whilst also avoiding pitting corrosion and crevice corrosion at elevated temperatures.

Landscapes

  • Coating By Spraying Or Casting (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)

Abstract

Un ombilical d'alimentation intégré (2) pour déploiement sous-marin comprend : un ou plusieurs cordons d'alimentation (4) pour fournir de l'énergie CA ; un tube métallique (10) adjacent audit cordon d'alimentation (s) (4) ; et un revêtement de zinc (12) recouvrant une surface externe dudit tube (10).
PCT/NO2019/050191 2018-11-07 2019-09-20 Ombilicaux d'alimentation pour déploiement sous-marin Ceased WO2020096458A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1818146.1A GB2578763B (en) 2018-11-07 2018-11-07 Power umbilicals for subsea deployment
GB1818146.1 2018-11-07

Publications (1)

Publication Number Publication Date
WO2020096458A1 true WO2020096458A1 (fr) 2020-05-14

Family

ID=64655571

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO2019/050191 Ceased WO2020096458A1 (fr) 2018-11-07 2019-09-20 Ombilicaux d'alimentation pour déploiement sous-marin

Country Status (2)

Country Link
GB (1) GB2578763B (fr)
WO (1) WO2020096458A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2255104A (en) * 1991-04-25 1992-10-28 Alcatel Stk As Corrosion protection for flexible submarine line
US6012495A (en) * 1996-09-05 2000-01-11 Alcatel Corrosion protection for subsea lines
US6472614B1 (en) * 2000-01-07 2002-10-29 Coflexip Dynamic umbilicals with internal steel rods
US20070251694A1 (en) * 2005-11-18 2007-11-01 Gwo-Tarng Ju Umbilical assembly, subsea system, and methods of use
WO2015038002A1 (fr) * 2013-09-12 2015-03-19 Aker Subsea As Faisceau de transport de charge destiné à être utilisé dans un câble d'alimentation ou un câble ombilical d'alimentation

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB506813A (en) * 1936-12-03 1939-06-05 Siemens Ag Improvements in or relating to pressure-proof trunk communication deep-sea cables
DE2939971A1 (de) * 1978-10-02 1980-04-10 Texas Instruments Inc Elektrisches netzkabel
US6960724B2 (en) * 2002-09-30 2005-11-01 Schlumberger Technology Corporation Dual stress member conductive cable
US7903914B2 (en) * 2008-05-19 2011-03-08 Deep Down, Inc. Method and apparatus for manufacture of a non-helical subsea umbilical
RU2497215C2 (ru) * 2009-07-16 2013-10-27 3М Инновейтив Пропертиз Компани Рассчитанный на работу под водой композитный кабель и способы его изготовления и использования
GB2554087B (en) * 2016-09-19 2020-01-01 Equinor Energy As Sacrificial anode protection of a subsea umbilical

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2255104A (en) * 1991-04-25 1992-10-28 Alcatel Stk As Corrosion protection for flexible submarine line
US6012495A (en) * 1996-09-05 2000-01-11 Alcatel Corrosion protection for subsea lines
US6472614B1 (en) * 2000-01-07 2002-10-29 Coflexip Dynamic umbilicals with internal steel rods
US20070251694A1 (en) * 2005-11-18 2007-11-01 Gwo-Tarng Ju Umbilical assembly, subsea system, and methods of use
WO2015038002A1 (fr) * 2013-09-12 2015-03-19 Aker Subsea As Faisceau de transport de charge destiné à être utilisé dans un câble d'alimentation ou un câble ombilical d'alimentation

Also Published As

Publication number Publication date
GB201818146D0 (en) 2018-12-19
GB2578763A (en) 2020-05-27
GB2578763B (en) 2020-12-16

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