Cathodic Protection (CP) Technology hauv Offshore Oil Thiab Gas Field Projects

Kev tiv thaiv Cathodic (CP, Cathodic Protection) thev naus laus zis yog qhov tseem ceeb hauv kev lag luam roj thiab roj av, feem ntau yog siv los tiv thaiv electrochemical corrosion ntawm cov chaw hlau (xws li platforms, pipelines, subsea equipment) raug dej hiav txwv, seabed av, thiab tidal zones.

Tsau Offshore Platforms (Jacket & Topside)

• Jacket Legs: Txhawb cov qauv rau hauv dej hiav txwv thiab seabed av nkos.
• Jacket tubular pob qij txha: Welded thaj chaw uas muaj corrosion.
• Sab saum toj kev txhawb nqa cov qauv: Submerged seem.

Subsea Pipelines

• Carbon steel pipelines: Sab nrauv phab ntsa raug dej hiav txwv; Cov phab ntsa sab hauv tuaj yeem thauj cov xov xwm corrosive (xws li CO₂, H₂S).
• Insulated pipelines (piv txwv li, yeeb nkab-hauv- yeeb nkab): Yuav tsum tau tsim tshwj xeeb los tiv thaiv cathodic shielding.

Subsea Production Systems

• Christmas ntoo, manifolds: High- cov khoom muaj nqis submerged ntev -lub sij hawm hauv dej hiav txwv.
• Jumpers, risers: Dynamic load cheeb tsam raug rau qaug zog corrosion.

FPSO (Floating Production Storage thiab Offloading Units)

• Hull: Steel daim hlau nyob rau hauv kev sib cuag nrog seawater.
• Ballast tso tsheb hlau luam: Muab cov chaw ntub dej uas ua rau corrosion.

Subsea Cables thiab Grounding Systems

• Cable armor khaubncaws sab nraud povtseg: Hlau armor khaubncaws sab nraud povtseg yuav tsum tau tiv thaiv corrosion.
• Anode grounding electrodes: Tiv thaiv kom tsis txhob muaj kev cuam tshuam tam sim no.

1. Sacrificial Anode CP (SACP)

Siv tau scenarios:

• Seawater ib puag ncig.
• Cov qauv me me lossis kev tiv thaiv hauv zos.
• Subsea cov chaw tsis muaj hluav taws xob.

Cov khoom siv anode:

• Aluminium alloy anodes: Feem ntau siv, tsav tsheb voltage -1.1V (vs. Ag/AgCl), lifespan 25-50 xyoo.
• Zinc alloy anodes: Tsav voltage -1.05V, haum rau qis-kub lossis dej qab ntsev tsawg.

Cov txheej txheem installation:

• Vuam los yog bolting (piv txwv li, platform ob txhais ceg, pipelines).
• Tshem tawm kev teeb tsa (piv txwv li, FPSO ballast tanks).

2. ImpRessed Tam sim no CP (ICCP)

Siv tau scenarios:

• Cov qauv loj (piv txwv li, FPSO hulls, offshore platforms).
• Siab -tam sim no-xav tau thaj chaw (xws li, qhov chaw hnyav corrosive lossis cov coatings hnyav heev).
• Deepwater tej yaam num (sacrificial anode hloov yog nyuaj).

Cov ntsiab lus tseem ceeb:

Cov khoom siv anodes:

• MMO anodes (Mixed Metal Oxide): Suitable for seawater, lifespan >20 xyoo.
• Platinum-niobium anodes: cov zis siab tam sim no, tiv taus cov acidic ib puag ncig.
• Transformer rectifiers: Hloov kho tam sim no raws li cov lus qhia electrode.

Daim ntawv thov electrodes:

• Ag / AgCl (seawater): Feem ntau, ruaj khov thiab txhim khu kev qha.
• Zn (cov ntaub ntawv siv hluav taws xob tas mus li): Siv nyob rau hauv qhov dej tob lossis cov av qeeg.

Cov txheej txheem installation:

• Distributed anodes (piv txwv li, ntau lub ntsiab lus anode ntawm FPSO hulls).
• Tej thaj chaw deb anode txaj (xws li, anode arrays rau subsea pipelines).
• Tensioned anodes.

1. Offshore Platform tiv thaiv

Kev kho mob anodes:

• Aluminium alloy anode blocks welded rau lub tsho ob txhais ceg thiab tubular pob qij txha.

Txaus siab tam sim no:

• MMO anodes tau nruab rau hauv qis dua platform rau cov platform loj.
• Siv cov electrodes deployed ntawm cov ntsiab lus tseem ceeb saib xyuas.

2. Subsea Pipeline Protection

Kev kho mob anodes:

• Aluminium alloy bracelet anodes clamped rau pipelines.
• Insulated pipelines yuav tsum muaj kev tiv thaiv- thaiv kev tsim qauv (piv txwv li, txheej txheej tshwj xeeb lossis anode layouts).

Txaus siab tam sim no:

• Cov kav dej sib sib zog nqus siv cov chaw taws teeb anode arrays (xws li subsea anode txaj).
• Offshore platforms siv cov chaw taws teeb lossis tensioned anodes.

3. Subsea Production System tiv thaiv

Christmas ntoo / manifolds:

• Aluminium alloy anodes ncaj qha mounted rau ntawm cov khoom siv.
• Standardized anode interfaces (xws li ISO 15589-2).

Jumpers:

• Kev txi anodes.

4. Kev tiv thaiv FPSO

Hull:

• ICCP systems nrog MMO anodes + siab -purity zinc siv electrodes.
• Ballast tanks siv tshem tawm aluminium alloy anodes.

Mooring systems:

• Chains thiab cables tiv thaiv los ntawm kev txi anodes.

1. Deepwater Environments (>1000m)

Cov teeb meem:

• Tsis tshua muaj kub thiab siab siab degrade anode kev ua tau zoo.
• Kev saib xyuas nyuaj uas xav tau ntev - lub neej tsim.

Kev daws:

• High-efficiency aluminium alloy anodes (piv txwv li, Al-Zn-In-Sn).
• ICCP systems nrog cov platinum txhim khu kev qha zoo heev -niobium anodes.

2. Cathodic shielding

Qhov teeb meem:

• Cov txheej rwb thaiv tsev los yog cov txheej tuab thaiv tam sim no los ntawm kev ncav cuag cov hlau.

Kev daws:

• Siv cov coatings conductive los yog cov qauv hlau liab qab hauv zos.
• Tsis txhob thaiv cov cheeb tsam hauv qhov chaw anode.

3. Dynamic Loads (piv txwv li, Risers, Jumpers)

Qhov teeb meem:

• Npuag kev nyuaj siab accelerate corrosion.

Kev daws:

• Saj zawg zog anode strips (piv txwv li, polymer cable anodes).
• Optimize anode faib kom txo tau kev ntxhov siab concentration.

4. Microbiologically Influenced Corrosion (MIC)

Qhov teeb meem:

• Sulfate-txo cov kab mob (SRB) vam meej nyob rau hauv seabed sediments.

Kev daws:

• Ua kom muaj peev xwm tiv thaiv (-0.95V vs. Ag/AgCl).
• Ua ke nrog kev kho mob biocide.

1. Muaj peev xwm saib xyuas:

• Tsis tu ncua diver lossis ROV tshuaj xyuas ntawm lub platform/pipeline muaj peev xwm.
• Txhim kho cov khoom siv hluav taws xob ruaj khov + cov ntaub ntawv loggers (piv txwv li, dej tob).

2. Anode hloov:

• Hloov cov anodes sacrificial thaum cov khoom seem<20% (via ROV or divers).
• Kev kuaj xyuas txhua xyoo ntawm ICCP rectifiers thiab kev siv anode.

1. Cov qauv thoob ntiaj teb:

• TS EN ISO 15589-2: Kev lag luam roj av thiab roj ntuj - Cathodic tiv thaiv cov kav xa hluav taws xob tsheb thauj mus los - Ntu 2: Cov kav dej tawm sab nraud
• DNV-RP-B401: Cathodic Protection Design.
• NACE SP0176-2022: Corrosion Control ntawm Submerged Area of ​​Permanently Installed Steel Offshore Structures Associated with Petroleum Production.

2. Suav cov qauv:

• SY/T 10008-2016: Corrosion Control rau Fully Submerged Zones ntawm Tsau Offshore Steel Petroleum Ntau Lawm Cov Qauv.
• SY/T 7699-2023: Txaus siab rau tam sim no Cathodic tiv thaiv rau Offshore Steel Structures.

• Petrobras Budzios-11 & Mero 4-11 Roj thiab Gas Field Subsea Production System
• TPAO Sakarya Gas Field Development Project Phase I Subsea Production System.
• CNOOC Lingshui 17-2 & 25-1 Gas Field Development Subsea Pipelines.
• Niger-Benin Export Subsea Pipeline Cathodic Protection Project.
• Bangladesh Single Point Mooring thiab Dual Subsea Pipeline Project.
• Dongying Chaw nres nkoj 250,000-tuj Crude Roj Ntshuam Terminal thiab Subsea Pipeline Project.
• CNOOC Lingshui 17-2 Semi-Submersible Production Storage Platform (FPSO).
• Qatar NOC Ruya Oil Field Development Wellhead Platforms thiab Subsea Pipelines.

Hauv kev lag luam offshore roj thiab roj, kev tiv thaiv cathodic yog cov thev naus laus zis rau kev tiv thaiv corrosion. Kev xaiv ntawm sacrificial anode thiab impressed txoj kev tam sim no nyob ntawm dej tob, ib puag ncig, thiab qauv hom, ntxiv los ntawm ROV xyuas, ntev -cov ntaub ntawv lub neej (xws li, MMO titanium anodes), thiab ntse tswj systems (xws li, transformer rectifiers). Kev tsim kom zoo txuas ntxiv cov chaw ua haujlwm ntev tshaj li 30 xyoo, txo cov nqi ua haujlwm thiab kev pheej hmoo ntawm kev tawg.