Fibre Optic Instrumented Pipeline Bundle for HPHT DevelopmentsSUBSEA EXPO February 2017

Mostafa Hendawy – Mechatronics Engineer

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• Introduction

• HPHT Theoretical Development

• Bundles HPHT Trial

• Results and Analysis

• Conclusions

Agenda

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Introduction • What is a Pipeline Bundle?

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Introduction• Why Pipeline Bundles?

– Onshore SIT and pre-commissioning;

– No need for specialist and expensive vessels;

– Less congested field layout;

– Improved flow assurance and thermal solution;

– No need for trenching / rock-dump;

– Fast hook-up and commissioning offshore;

– Year round installation (with enhanced weather criteria).

• Pipelines bundle operating temperature range is currently at 160°C.

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HPHT Theoretical Development• Pipeline bundle pre-tensioning advantages:

– Suitable for 220°C, 1379 bar;

– Reduction of compressive axial forces due to high temperature;

– Mitigate the need for expansion spools.

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HPHT Trial – Mechanical Setup

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HPHT Trial – Instrumentation Setup

Fibre Optic Instrumentation FBG Chain

Strain gauge Instrumentation

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HPHT Trial – Testing Procedure• Pressure Strength test (1 cycle):

– Hold points: 35bar, 169.2bar, 253.8bar and 287bar.

• Mechanical Pre-tensioning test (3 cycles):– 4 pre-tensioning steps (104mm each; i.e. 416mm total);

– Flowline extends by 253mm;

– Sleeve compresses by 163mm.

• Unrestrained HPHT test (2 cycles):– Temperature applied 220°C;

– Pressure applied 193bar

• Boulder case test (1 cycle):– Temperature applied 220°C;

– 300mm prop bend.

– Pressure applied 193bar

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Results - Pressure Strength Test

Strain gauge results (hoop and axial strains)

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Results - Pressure Strength Test

Strain gauge results (hoop and axial strains)

Hoop strain at pressure hold points

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Results - Mechanical Pre-tensioning Test

Jacks & extension legs installed During Jacking, installing packers

All packers installed Insulation and half shells installed

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Results – Mechanical Pre-tensioning Test

Strain gauge results (hoop and axial strains)

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Results – Mechanical Pre-tensioning TestAxial strain at Pre-tensioning steps

Strain gauge results (hoop and axial strains)

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Results – Mechanical Pre-tensioning Test

Instrumentation technology comparison (axial strain)

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Results – Unrestrained HPHT Test

Strain gauge results (hoop and axial strains)

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Results – Unrestrained HPHT Test

Strain gauge results (hoop and axial strains)

Temperature:Axial strain drop

Pressure:Hoop strain rise

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Results – Unrestrained HPHT Test• Distributed Temperature Sensing Video 3 heating cycles

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Results – Boulder Case Test

Distributed Axial Strain Sensing Results (DSS)

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16:19:12 17:31:12 18:43:12 19:55:12 21:07:12

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Date and Time

Axial Strain 2 IP (µε)

Axial Strain 3 IP (µε)

Temperature Max. (ᴼC)

Results – Boulder Case Test

Strain gauge results (axial strain)

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Conclusions• Trials performed safely in presence of third party.

• Pre-tensioning system generated strains within 7% of the FEA results.

• Friction coefficient was insignificant (0.17) due to the use of Subsea 7’s low friction HT centralisers (Patent Pending).

• Strain gauges verified the FEA model and the FO instrumentation results.

• Results are all within 90% accuracy of the maximum strain value during the given test.

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Conclusions• Subsea 7 demonstrated the technology required to pre-

tension bundles for HPHT applications up to 220ᴼC.

• Subsea 7 demonstrated the technology required to use fibre optic and/or strain gauges for monitoring pipeline bundles during pre-tensioning and operational phases.

• Qualifications according to DNV-RP-A203 almost complete.

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