requirements to elastomers used in subsea...

Requirements to elastomers used in Subsea Applications

Øystein Skottun Lyngdal, Material Engineer, FMC Technologies 15th May, RubberCon 2012

Outline

• FMC Technologies

• Seal Requirements

• Chemicals used in the Oil & Gas Industry

• Seals in FMC Technologies

• Compatibility Tests

• Conclusions

FMC Technologies

15th May, RubberCon 2012

History

1974 - Kongsberg Våpenfabrikk, Oil Division established

1986 - Kongsberg Offshore a.s (KOS) established

1987 - Kongsberg Offshore sold to Siemens

1993 - Kongsberg Offshore sold to FMC Corporation

(Food Machinery Corporation from 1884)

2000 – Changed name to FMC Kongsberg Subsea AS

Today, FMC is the worlds leading supplier of subsea equipment

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Houston

Kongsberg

Singapore

Dunfermline

Rio De Janeiro

Global Presence

Asker

Kristiansund

Bergen

Kongsberg

FMC Technologies in Norway

Stavanger

Seal Requirements


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Typical technical requirements

• Water depths: 300 to 2300 m

• Reservoir pressures: up to 15.000 psi (1035 bar)

• Temperatures: -30˚C up to +170˚C

• Design life: ~ 25 years – RGD resistant materials

– Compatibility with chemicals

• More documentation required from customers

Future requirements

• High pressure, High temperature – Pressures of 15 ksi and higher

– Temperatures above 170 C

• Arctic environment – Storage down to – 50 C

– Pressure test on deck down to – 20 C, without damage to seals or insulation

– The elastomer shall still operate without failure up to 121 C

Chemicals used in the Oil & Gas Industry


Typical fluids

• Environmental fluids

– Air , Sunlight , Water

• Production and injection fluids

– Gaseous & liquid hydrocarbons (C1 – C10+), CH4, CO2, H2S

• Hydraulic control fluids

– Water based; Water / glycol with low concentration of metal corrosion inhibitors (with amines), surfactant, biocide, dye etc.

– Synthetic oil based; Hydrocarbon (poly-alpha-olefin) oil with low concentration of biocide, surfactant, dye, corrosion inhibitors etc.

• Preservation fluids

– Water/ MEG, Methanol, Diesel

• Hydrate inhibitors

– Methanol, MEG, DEG

• Corrosion inhibitors

– Amines, aromatic naphthalene, toluene,

xylene etc

• Scale inhibitor

– Acetic/formic/phosphonic acid (<5 %), HCl (<10 %) etc.

• Wax inhibitor

– Aromatic solvents

• Asphaltene inhibitor

– Aromatic naphthalene, toluene, xylene etc. (non-polar)

Typical fluids

Seals in FMC Technologies

NGF Høstmøte, Åsgårdstrand 08.09.2011

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Areas of application for elastomers in FMC Technologies • Seals/gaskets for pressurized equipment both for drilling,

production, injection and service lines. Are in contact with hydrocarbons, hydraulic fluids, different injection chemicals (methanol, glycol, amines, acids, solvents etc), sea water etc

• Coatings for corrosion protection

• Thermal insulation to avoid hydrate/wax formation during shut down of production

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Seals and materials choices

• Production systems: Metal-to-metal primary seals. Elastomer secondary seals. HNBR dominates

– All seals NORSOK M-710 qualified

• Hydraulic systems: NBR, HNBR and Viton typical. Many different materials used.

– Compatibility tested when new fluids are introduced

• Chemical injection systems: High chemical resistance materials, PEEK, PTFE, FFKM dominates.

– Injections chemicals decided at a late stage in projects, a challenge for the materials compatibility testing!

FMC Seal requirements

• Typical requirements in the specifications: – Temperature and pressure (static and dynamic)

– Mechanical properties

– Compatibility requirements

– NORSOK M-710 / ISO 10432

– Formulation (ACN & oil content, peroxide cured)

– FMC compound or approved vendors

• Quality more important than the prize

Non-Metallic Materials Compatibility Report

• Report for all new projects

• Fluids identified

• Lists non-metallic materials exposed to these fluids in permanent equiptment

• Documents compatibility – Compatibility testing

– Field experience

Compatibility Tests


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Industry Standards

• Norsok M-710 - Qualification of non-metallic sealing materials and manufacturers

• ASTM D 471 - Standard Test Method for Rubber Property—Effect of Liquids

• ISO10423 – Petroleum and natural gas industries – Chapter F 1.13 Testing of non-metallic seals

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Norsok M-710

• Chemical Aging and Rapid Gas Decompression (RGD)

• Pure material testing, not for functionality testing of actual seals

• Covers elastomers and thermoplastic materials

• Test fluid:

– Sweet or sour production fluid

– The actual exposure environment

• Three different temperatures, all above service temperature

• Lifetime estimation in an Arrhenius plot based on changes in tensile properties

• Acceptance criteria given for elastomers and thermoplastic materials

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• Chemical Aging

• Pure material testing, not for functionality testing of actual seals

• Covers elastomers

• Test fluid:

– IRM 902 or 903 (replaces ASTM Oil no 1 and No2)

– Gasoline or diesel fuels use one of 10 ASTM referenced fuels

– The actual service liquid

• Test temperature depended on the anticipated service conditions

• No lifetime estimation specified

• No acceptance criteria given

ASTM D 471 - Standard Test Method for Rubber Property—Effect of Liquids

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ISO10423 – functional testing of seals

• Used for functional testing of elastomer seals exposed to sweet or sour production fluid

• Annex F1.11 used for temperature pressure cycle/sealing testing of actual equipment

• Annex F1.13 used for chemical exposure testing of seals

– Fixture testing

– Chemical aging

– Temperature and pressure cycles

– Leakage acceptance criteria

Chemical Compatibility Testing - Challenges

• Chemical Aging of rubber at service conditions is a difficult case to treat. Most of the studies are based on life time estimation from accelerated aging test where the data are extrapolated to service conditions. Extrapolation is uncertain.

• New fluids are introduced for every project and often changed during production of hardware.

• Fluids are sometimes changed after production of hardware.

• Operating temperatures higher, close to the temperature limits of the elastomers.

• Appropriate acceptance criteria are difficult to define.

Conclusions


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• NBR, HNBR, FKM and FFKM rubbers are frequently used in FMC

• FKM should be avoided in most applications due to amine degradation

• Documentation requirements enhance the need for testing

• New temperature, pressure and compatibility requirements, and the lack of fluid information, challenge existing rubber quality

• FMC works actively with compatibility testing and qualification of non-metallic materials – FMC wish to obtain fluid information at an early stage

– Operating temperature / pressure should be as close to reality as possible

• Through collaborations, we seek to develop new non-metallic materials

• FMC is constantly searching for new materials to improve our product portfolio

Conclusions

Thank you for your attention!