Integrity Management of Riser and Subsea Systems

Steve HattonPeter Falconer

Thursday, 21 February 2008

About 2H Offshore

Established in 1993

Involved in the design of riser systems and specialist subsea components

Provides independent advice on design, assessment, inspection, mitigation, and monitoring requirements

Pioneered the process of Integrity Management for Deepwater Risers

Background - Market Need

Risers are welded tubular structuresState of the art design with complex loading

Fatigue critical

Complex installations, pushing boundaries of equipment

Short operational history

Failures are unacceptable

Subsea, flowlines and pipelines are similarly important

Riser & Subsea Assurance

2H have been involved in Riser & Subsea IM for

more than 10 years

On one contract alone 2H are currently

responsible for:

8 deepwater field developments

7 types of risers

3 different hull forms

Increasing industry, and regulatory body, interest

as need and benefits become understood

Objectives: To operate and maintain a pipeline & risers in a manner that protects life, property, and the environment for the service life of the asset

Life of field protection

Operations IssuesPersonnel changesService changesReservoir changes

AccidentsEventsExpertise

DesignFabInst

CorrosionFatigue

Providing effective barriers?

Integrity management

How often should we inspect?

How much monitored data

should we collect?

How critical is our next intervention?

How often should we inspect?

How much monitored data

should we collect?

How critical is our next intervention?

Risk management

Confidence Rating

Criticality Very Low Low Medium High Very High

Extreme Manually assign inspection interval/ determine monitoring

Very High a b b c d

High b b c d e

Medium b c d e f

Low c d e f g

Negligible d e f g h

Inspection requirements

Coating damageAnode degradationTSA depletion

Missing fairings Excessive marine growth

Monitoring

CorrosionAccelerationsInclinationAngular rate DisplacementsStress and strainsCurvatureHeadingPressureTemperatureEnvironmental

Continuous process

Fatigue tracking methods

2: Environmental1: Structural

Often measuring:

Riser tension and stroke – in conjunction with vessel motion and environment

Typical arrangement:

3 or more load cells allowing bending moment to be determined

ROV installed motion loggers

Internal annulus pressure

Top tensioned riser response data

ASSURE Systems and INTEGRI Products

moorASSUREflexASSUREttrASSUREdrillASSUREscrASSUREslorASSURE

INTEGRIpod M – Stand alone Motion loggerINTEGRIpod MA – Acoustic Motion loggerINTEGRIstick – Bending INTEGRIcollar – Tension / bending INTEGRIcuff – Mooring Chain

Integrity SystemsUsingMonitoring Products

Summary

IM programme is critical in maintaining subsea and riser assurance

Competence of team is essential

Inspection must be looked at in conjunction with effective monitoring

Aims should be identified before installing monitoring systems

Subsea monitoring offers significant benefits to risk reduction

Monitoring systems are effective in providing early warning of anomaly development and to confirm integrity

2H is established as a market leader