Industry standards – a blessing or a curse?

Alexandra Torgersen NGF Høstmøte 2013 2013-ATE-PN-104

Special challenges facing soft seal solutions

Floating Production Storage & Offloading Vessels

Turret Mooring Systems

Tension Leg Platforms

Light Well Intervention

Guidelineless Deepwater Trees

Subsea Manifold Smart Well

Control Systems Subsea Template Systems

Standard Subsea Trees

Metering & Control Systems

Surface Well Systems

ROV Tie-In Systems

Subsea Processing

Subsea Drilling Systems

Oilfield equipment

Production environments

• Subsea production: Seals, gaskets, packoffs, connectors, diaphragms.

• Temperatures from - 50 oC to 180 oC possible. Pressures up to 1,000 bar differential.

• Resistance to production/injection fluids, gases, chemicals, acids.

• Mechanical abuse is less than drilling.

• Subsea applications are very critical due to cost (millions of $) and environmental issues.

• Service life of 20 to 30 years or more.

Failure mechanisms

• Mechanical • Extrusion • Chemical • RGD

Industry requirements

What is the basis for industry standards?

• Common minimum requirements for specific equipment

• Collective industry knowhow and understanding

• Eliminate common mistakes/challenges • Guide to ensure fit form and function

Why do we need them?

• Alternative is every company making their own rules

• Assist and guide newcomers to understand challenges in industry

• Assist and guide everyone deliver equipment that works

Do the standards cover everything?

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Offshore development

©Statoil

Wells/Downhole equipment Material Selection Fabrication Fatigue High temperature

Flowlines Material Selection Plastic deformation High temperature Corrosion inhibitors CP Coating

Risers Material Selection Fabrication Fatigue

Export pipelines Fabrication Running fracture

Hull Fabrication CP/ coating

Topsides Material Selection Coating

Subsea XT and TM Material Selection Fabrication Fatigue High temperature CP/ Coating HISC

Drilling/ Workover Material Selection Fabrication Fatigue

ISO 13628/API 17 ISO 10423/API 6A

DNV OS-F101 DNV OS-F101

DNV OS-F201

NORSOK

NORSOK/ISO/API

DNV DNV Class Rules

Typical subsea industry elastomer testing philosophy

• Production system: all seals typically qualified per NORSOK M710, ISO23936, and ISO10423 (API 6A)

• Hydraulic system: many seals accepted as field proven. ISO 13628-6 covers materials testing.

• Chemical injection system: primarily metal seals or thermoplastic seals (PEEK, PTFE) which have very high chemical resistance. Elastomers typically tested (immersion testing). No specific industry standards, but can be covered using NORSOK M710, ISO 23936. Often ISO 1817 is used.

• Completion fluids: exposed seals tested (immersion testing) in completion brines. No specific industry standards, but can be covered using NORSOK M710, ISO 23936. Often ISO 1817 is used.

Industry standards • Subsea production seals:

– NORSOK M710 – ISO 23936 – ISO 10423 / API 6A

• Subsea hydraulic fluid seals: – ISO 13628 part 6

• Downhole seals: – ISO 13533 – ISO 16070 – ISO 14310

• General: – ISO 1817

NORSOK M710 –production fluid seals

• Scope: production seals – Seals wetted by production fluid

• Provides methodology for qualification of materials and manufacturers

• QC requirements • Material standard only, no functional

requirements or testing

NORSOK M710 – Service life prediction

• Methodology: – 3 test temperatures – Durations long enough to achieve >50% drop in

tensile properties – Standard test fluids; sweet and sour service.

Bespoke fluid is an option. – Arrhenius extrapolation of test results to provide

service life at different temperatures

NORSOK M710 – Service life prediction

• Benefits: – Very good comparison tool for evaluating different material choices – Provides indications of service life at temperature based on

extrapolation – Long test times provide understanding of degradation behavior in

material • Challenges:

– Method not suitable if deterioration is not linear – Unsuitable if no deterioration occurs, or if reaction is abrupt – Comparison tool only, not suited to give absolute application driven

parameters – Pure material test, not application specific – Uncertainty in accuracy of extrapolation

• Methodology: – Test jig with O-rings exposed to a standard gas

mixture – Temperature either 100°, 150° or 200°C – most

testing done at 100°C – Pressure set at 150 bar – 10 decompressions – Evaluation of O-rings after decompressions

NORSOK M710 – Rapid Gas Decompression

• Benefits: – Easy comparison between materials – Good method for understanding level of resistance to

RGD in individual materials • Challenges:

– Testing done on unsupported O-rings – Supported seals with good design may function

despite failure in RGD test – Not directly translatable to real applications – Testing done at lower temperatures and pressures

than normally seen in applications

NORSOK M710 – Rapid Gas Decompression

ISO 23936 – production fluid seals

• Part 1 thermoplastics – will not be covered as this is not typically used in the industry. Not a good standard.

• Part 2 elastomers – based on NORSOK M710. This standard will most likely replace NORSOK M710 for elastomer requirements.

ISO 23936 – 2

• Same scope and methodology as in NORSOK M710 – elastomers only

• Also covers hoses, flex joints, downhole packers, bridgeplugs and BOP seals – Materials testing is same as for production seals

• Provides methodology for qualification of materials and manufacturers

• QC requirements • Material standard only, no functional

requirements or testing

ISO 10423 / API 6A – WH, XMT, WO

• Scope: functional requirements for wellhead (WH), Xmas tree (XMT) and workover (WO) equipment

• Annex F provides functional test requirements for non-metallic seals

• QC requirements

ISO 10423 Annex F1.11 (PR2 test) • Methodology:

– Cyclic temperature and pressure testing of sealing system using actual seal and gland

– Temperatures: TMin, TRoom, TMax

– Pressures: PNom, PMax

– Test medium: water / water based fluid or Nitrogen gas

– Hold points: 1 hr – Acceptance criteria: pressure

drop

ISO 10423 Annex F1.11 • Benefits:

– Functional test of actual sealing system – Gas medium provides applicable testing for

gas sealing systems – Sealing at both low and high temperatures is

a challenge, and thus design is verified to full range of application

• Challenges: – Acceptance criteria of pressure drop too

lenient for gas applications: should use «zero bubbles»

– Pressure releases may occur too rapidly and cause inadvertent RGD effects – needs to be controlled

ISO 10423 Annex F1.13

• Methodology: – Immersion test using actual seal and groove – Test fluid is sweet or sour service – Temperature and pressure is max for application – Duration is 160 hrs – Post exposure pressure testing at high and low

temperature with sealing as acceptance criteria

ISO 10423 Annex F1.13 • Benefits:

– Methodology combines functional testing and exposure testing – Acceptance criteria of no leakage proves functionality after exposure

to production fluid • Challenges:

– Exposure duration too short for any real measure of long term effects – Does not cover RGD effects

ISO 13533 – BOPs • Scope: functional testing of

BOPs, both RAM type and annular type

• Material requirements not covered, should use ISO 23936

• Testing covers both sealing function, shear function and temperature/pressure cycling

ISO 14310 – Packers and bridge plugs

• Scope: Functional standard covering packers and bridge plugs for down-hole applications

• Several levels of validation testing – V5 to V0, where V0 is the most stringent level.

• V0 requires gas sealing tests at temperature and pressure with zero bubbles as acceptance criteria.

• Requirement for manufacturers are included in standard

ISO 13628-6 – hydraulic fluids • Scope: functional and

material testing of hydraulic fluid – may also be used for polymer/elastomer materials

• Annex C covers qualification of hydraulic fluid

• Standard not specifically written for qualification and testing of materials

Different NBR’s exposed to control fluid

ISO 13628-6 • Methodology:

– Immersion type testing of materials in hydraulic fluid

– Temperature: 70°C and TMax

– No pressure required – Duration up to 3 months with

intermediate durations at 1 week and 1 month

– Post exposure testing do not include tensile testing

ISO 13628-6 • Benefits:

– Generic test for all types of materials in hydraulic fluids – Easy to compare different materials – Long test duration

• Challenges: – Lack of mechanical testing of materials required – Only two temperatures makes it impossible to perform

Arrhenius extrapolations – No functional testing of sealing systems required

Soft Seal Qualification Guideline

• Guideline that describes scope for relevant subsea soft seal industry standards – what it DOES test for and what it DOESN’T test for ….

• Gives both benefits and challenges with each standard

• Provides tips on how to best use each standard

Qualification summary • Standards offer a set of rules and regulations for soft seal

qualification – however it is always «fit for service» that is ultimate goal

• Many applications not well covered by standards • Many service environments outside standard

temperatures, pressures and chemistry covered by standards

• Use standards as guide to qualification testing, NOT as the Bible – the application must always come before industry requirements

Concluding remarks

• Industry standards are perhaps a blessing AND a curse

• Fit for purpose is the ultimate qualification criteria

• Standards and guidelines are minimum requirements, and should be combined with knowledge, experience and specific needs