bp pipeline management riskassessment, operation ...¸rledninger... · gp 43-50 pigging, pig...

PTIL seminar on pipeline integrity 9. December 2009

BP Pipeline ManagementRisk assessment, operation experience

and lessons learned

Per Olav Gartland, John Berget and Bente Herfjord

FORCE Technology Norway AS

and

Inge J. Mæland and Alf Inge Lyse

BP Norway


Pipeline Integrity Management

to ensure the technical integrity of the pipeline, i.e.: to operate within acceptable safety margins and optimised economy throughout the lifetime

» avoid failures and incidents

» re-qualification and life extension of old pipelines

» optimize life cycle cost (LCC)


BP Norway PIM Strategy

Risk AssessmentEvaluate internal/external conditionIdentify critical parameters and accept criteria (KPI s)

MonitoringCorrosion monitoringCritical process parameters (KPI`)Free span, burial, CP etc.Status Reporting (quarterly)

Inspection Internal and external inspection plansDetail inspection planning (scope, inspection method/practical arrangements etc.)Inspection (ILI, ROV)Evaluate inspection results/finding & take actions

Maintenance activitiesCleaning (pig)General maintenance of valves and pig receivers and launcher.

Risk Assessment

MonitoringInspection plan

Implementworkscope

Execute MonitoringInspection

EvaluateFindings

Actions

INSPECTION & CORROSION MANAGEMENT

Follow up

Update plan

Control


BPs Engineering Technical Practice ETPs

PR 43 Pipeline ETP Rationale and PhilosophyGP 43-17 Pipeline Risk ManagementGIS 43-213 Pipeline Spanning (DNV RP F105)GP 43-23 Offshore Facilities for PipelinesGP 43-24 GIS and MappingGP 43-26 Offshore SurveysGP 43-36 Pipeline ProtectionGP 43-37 Control Systems for PipelinesGP 43-39 Measurement and Sampling on PipelinesGP 43-48 Pipeline Operations Organisation Setup

GP 43-49 Pipeline Integrity Management Systems (PIMS)GP 43-50 Pigging, Pig Launchers, and ReceiversGP 43-51 Maintenance and Reliability

GP 43-52 Inspection and Integrity Assessment of PipelinesGP 43-53 Pipeline Intervention and Repair


INTERNAL Load effects

Corrosion caused by

CO2 / HAcH2SBacteria (deposit)

Erosion caused byparticle (sand)

EXTERNAL Load effects

CorrosionCP system malfunctionCoating qualityBacteriaHISC

Ground movementsEarth quakeSoil movements

3rd party damageImpact (anchoring etc.)Sabotage

Mechanical defectsFatigueVibration

Risk AssesmentFailure Mechanisms during Operation

RISK = Probability (PoF) x Consequence (CoF)


Internal Risk Assessment

Quantitative assessment based on:Corrosion features from In-line Inspection (ILI)CorPos-AD pipeline corrosion model

CO2 (Norsok M-506), HAc, H2S, erosionAdditional models (Cassandra) to be implemented

Model combined with ILI dataQualitative assessment

Bacteria corrosion

Integrity check based on DnV RP-F101Remaining Lifetime EstimationTime to next inspection Monitoring program parameters and associated critical values


CorPos-AD

Database

Graphs

Risk analysis andSafety Check

Corrosion modeling

Flow modelingOLGA

Import inspection data

Import monitoring data

Import production data

Import chemical injection data

Reports

Combine corrosion modeland monitoring/inspection

CorPos-AD, overview


Case 1: Hod 12 Multiphase pipeline


Case 1: Hod multiphase pipeline ILI

Hod

0.0

2.0

4.0

6.0

8.0

10.0

12.0

mai.90 jan.93 okt.95 jul.98 apr.01 jan.04 okt.06 jul.09 apr.12

Time

Co

rro

sio

n d

epth

(mm

) Inspection dataMFL UT

12 Hod multiphase pipeline (CS)

Operation from 1990

ILI 1993, 1994, 1995, 1998, 2004, 2009

Corr. Inhibitor injection 1993


Case 1: CorPos-AD analysis of Hod multiphase pipeline

CorPos-AD analysis basedon:

Production dataInhibitor injection dataCR-profile obtained for 4 time periodsMax corroded depth vstime from integration

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 2000 4000 6000 8000 10000 12000 14000

KP [m]

Cor

rosi

on r

ate

[mm

/ yea

r]

CR (1991-1993)

CR (1993-1998)

CR (1998-2000)

CR (2001-2008)


Case 1: CorPos-AD analysis of Hod multiphase pipeline

Hod

0.0

2.0

4.0

6.0

8.0

10.0

12.0

mai.90 jan.93 okt.95 jul.98 apr.01 jan.04 okt.06 jul.09 apr.12

Time

Co

rro

sio

n d

epth

(mm

)

Inspection data

Corpos-AD analysis 2009


Case 1: Hod Multiphase pipeline CorPos-AD Risk Assessment

ILI data from 2008Design lifetime = 7 years (2015)Risk status at end ofdesign life = OKEstimated remaininglifetime > 50 yearsFuture ILI frequency 5 years

Zone 1- Pit growth prediction

Critical pit depth according to DnV RP-F101

Blue lines: Pit growth model prediction from 2008 to 2015


Case 1: Major challenges

Wax deposits in pipelineUT pig data more sensitive to residual wax than MFL pig dataMFL and UT data have different accuracy and resolutionModification of pig hardware and software over time makes it difficult to evaluatetime evolution of corrosionfeatures (e.g. to extractcorrosion rates)


Case 1: Hod Multiphase - Corrosion Monitoring

Quarterly status reporting:


Case 2: Ula - Ekofisk 20 oil export pipeline

Ula

Tambar

Cod

20 UTS PipelineLength: 70 km from Ekofisk to Ula

13 km from Ula to Y Assembly

Ekofisk 2/4 J

Gyda

Ula/Gyda Wye

Assembly

10 Cod Gas Export (Decommisioned)Length: 26.4 km 8 Tambar Production Flowline

(Decommisioned)Length: 16 km

20 Gyda Oil Export PipelineLength: 24.8 km

10 Spool from Tambar to UGIPLength: 60 m

36 Ekofisk to Teeside

Total length 170 km


20 UT pig Launching..



Production start in 1986

UT

MFL

MFL

Method

Pitting with depth up to 4.4 mm before Y-connection

Pitting with depth up to 6.9 mm before Y-connection

No findings

Findings

2006

2004

1997

Time of inspection

2006 ILI



Low production ratesIncreased water holdup Dilution of inhibitor

Changes leading to improved corrosion control

Increased inhibitor injection ratesIncreased frequency of cleaning pig runsIncreased frequency of intelligent pig runsIncreased production rate (Tambar)

CorPos/OLGA analysis

0

5

10

15

20

25

30

1992 1994 1996 1998 2000 2002 2004

Year

Max

wat

er h

old

up

(%

)

Before Y-connection

After Y-connection



Quarterly status reporting:


Lessons Learned (1)

Proper cleaning of pipelines prior to inspection is very important to ensure good / reliable and comparable inspection data.

Good planning and coordination of the operation is important to ensure effective utilization of expensive rental equipment (cleaning pigs and inspection tools)

Dimension control by gauge plate

Hook devices both in front and back of the cleaning/ inspection pigs to ease the pig launch and retrieval from pig launcher / receiver.


Lessons learned (2)

Data on corrosion rates (CR) required for lifetime estimationILI data strongly dependent on method (MFL, UT) and method development Difficult to obtain corrosionrates from ILI dataNo corrosion monitoring units on pipelines. Probes top-side not relevant for the entire pipeline.Good experience from using CR data obtained from CorPos-AD model, adjusted to fit ILI data if required

Low production rates may lead to water accumulation and poorinhibitor performance in oil export lines with low water content(1-2 %) High frequency of cleaning pigs required


Major challenges in the future

InternalMIC (Microbial Influenced Corrosion)

ExternalHow determine anode depletion for buried pipelines?How to inspect for HISC risk of CRA pipelines?

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