Different solutions to inspect platform risers

By:

Robert van Agthoven (Part I)Manager Marketing & Sales PS-PITRotterdam, The Netherlands

Charles Lawther (Part II)Technical Manager Offshore Business UnitAberdeen, Scotland

Event:PPSA SeminarNovember 14th, 2007 Aberdeen

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Contents of the presentation

Focus on inspection of “unpiggable” risersThe operational conditionsType of defects that can be detectedTravel capabilities and range of tethered toolsDeployment examplesNear future challengesOther possibilities for non-intrusive inspections of risers in Part II of this presentation

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Different “unpiggable” riser-lay-outs

WELL

J-TUBE

OPEN?

TIDAL ACTIONINSIDE J-TUBE

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Inspection options & conditions

Off-stream: Open access, allows

internal inspection with tethered UT-tool, also where OD is not accessible (e.g. J-tube)

Riser must be liquid filled for UT-inspection

Liquid may be: crude oil, (sea) water, condensate

For gas risers: use high-friction sealing pig and limited volume of water

On-stream: Must be accessible from

OD Requires diver or ROV

assistance, Apply “screening” tool to

assess general condition

Advantage:No shut-down required

Advantage:UT tools provide quantitative data

A screening tool called “Incotest“ will be explained in part II of this presentation

GAS

HIGH-FRICTIONSEALING PIG

WATER

UT-INSPECTIONMODULE

TETHER

RISER

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What can be detected with ultrasonics,using a tethered inspection tool?

OD CORROSION

ID CORROSION OVALITY / DENT

WALL THICKNESS

ID GEOMETRY WELD INSPECTION

CRACKS?FATIGUE CRACKS?

STOP & SCAN WELD

TOFD

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Tethered vehicle capabilities

CONCRETE BASEPLATFORM

STEE

L ST

RUCT

URE

GRAVITY DRIVEN CRAWLER DRIVEN

LIMIT

TOOL ACCESS TOOL ACCESS

CRAWLER CAN PASSBENDS AND HORIZONTALSECTION(S)

LIMIT=CABLE LENGTHAND BENDS

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100% circumferential coverage = MUST!

TRANSDUCERS

32 or 64Fixed Ultrasonic sensors,

Equidistantly divided

Option #1 Option #2

1 rotating sensor,# of measuring points

programmable

REV #1REV #2REV #3

SCAN ALONG HELICAL PATH

Lay-out of ID surface

Lay-out ofwall thickness

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Deployment of Riser Inspection Tool

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Near future challenges

2000 mwater depth!

•SCR’s•TTR’s

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Conclusions - Part I

Today many solutions exist to inspect “unpiggable” risers

For diameters from 4-60”, distances up to 10 km.Both gravity and self-propelled tools do not require liquid-handling or pumping, liquid remains stagnantAccurate tool handling and positioning in vertical section, free-swimming ILI tool cannot stop and may go too fast.Only short inspection window required (few hours)Ultrasonics provide quantitative results with no wall thickness limitationsReinforced tether adds to safety, tool can always be retrieved and allows on-line presentation of results.

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Questions?

After presentation of Part II by Charles Lawther