Underwater Inspection Structure & Pipeline

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Underwater Inspection Structure & Pipeline,

Repair of Subsea PipelineAuthor: Salvatore Oliverio

San Donato Milanese 15 October 2012

Master in Petroleum Engineering 2011-2012


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Underwater Inspection Structure & Pipeline, Repair ofSubsea Pipeline


Author

Ing. Salvatore Oliverio

Division Exploration & Production

Dept. MANUT

Company Tutors

Ing. Francesco Gasparri

Ing. Roberto Bianchinotti

UniversityTutor

Prof. Ing.Francesca Verga

Master in Petroleum Engineering 2011-2012


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Project Scope

Types of Inspection Sealine Repair Scenarios

Case Study

Conclusions

Agenda



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Project Scope

Study of main technologies used for the inspection andmaintenance of subsea pipelines

To understand how to use these technologies in differentscenarios

Case Study: Problem Analysis and best solution


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Project Scope

Types of Inspection

Sealine Repair Scenarios

Case Study

Conclusions

Agenda



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Types of Inspection

Assurance ofsuitablepipelinesafety level, preventing HSERisks (safeguard of environment and people)

Minimization of productionlosses due to period ofdowntime

Minimization of costsfor repairing works

Compliancewith obligations and regulations

Why?


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Types of Inspection

There are five types of inspections, or examinations,depending on the procedures and means adopted

General Visual Examination (GVE)

Close Visual Examination (CVE)

Non-Destructive Tests (NDT)

Flooded Member Detection Test (FMD)

Measure of Cathodic Protection (MCP)


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Types of Inspection: General Visual Examination

Significant deformation (misshapen)or fracture of steel tubulars

Mechanical damage caused bycollisions or falling objects

Leaks from the risers

Condition of the risers and clamps,

including 50 m distance of sealine

State of conductor pipes, payingspecial attention to any anomalousvibrations

Examination of the state of conservation of the jacket/sealineand reveals any evident defects or damage


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Types of Inspection: Close Visual Inspection

The condition of certain anodes

Corrosion

Mechanical damage

Welds of joints and of the main andsecondary elements

The detailed visual inspection is carried out to detect defects

or damage which are visible but not evident,and document them


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Types of Inspection: Non-Destructive tests

Non destructive tests are used to highlight fractures and

other defects, superficial or internal, and assess theirnature, location and dimension

Magnetic Particle Inspection

Alternate Current Field Inspection

Ultrasound Test


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Types of Inspection: FMD Test

The FMD (Flooded Member Detection) inspection serves toidentify any cracks through the whole thickness of a tubular

by checking for flooding of the element

flooding of the element

ROV equipped video camera and gamma ray


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Types of Inspection: Measure of Cathodic Protection

The submerged parts are protected against corrosion byanodes of aluminium, zinc or magnesium alloys or using an

electrical current

measurements of thepotential of the structureand galvanic anodes

measurements of the sizesof galvanic anodes

anode sampling forchemical andmetallographic analysis

profiles of the potential andof the potential gradient ofsubmerged pipelines


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Project Scope

Types of Inspection


Case Study

Conclusions

Agenda



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Depending on the extension of the damage, repair can involve

Local repair methods in case of localized damages like dents,gouges in the steel wall, cracks on weld seams

Change of the damaged section for more extended damages thatcannot be accepted, such as damages that lead to pipelineleakage


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Sealine Repair Scenarios: Local Damage

The main typical damage:

Pin hole leak

Pipe external damage

Damages to pipe bends

Leaking flanges


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Sealine Repair Scenarios: Extended Damage

Factors that influence the best solution:

Water depth

Extent of damage

Diameter of pipeline


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METHOD SELECTION

Sealine Repair Scenarios: Operations

LOCAL DAMAGE

what is procedure?

REPAIR ACTIVITIES

DAMAGE EVALUATION

SEA-LINE PREPARATIONcleaning failureproduction stoppingand sealine cutting

what is clamp?

EXTENTED DAMAGE

RECOMISSIONING

RISK EVALUATION

LEAK TEST

METHOD SELECTION

SEA-LINE PREPARATION

RISK EVALUATION


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Project Scope

Types of Inspection


Case Study

Conclusions

Agenda



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Case Study: Inspection Scenario

TECHNICALOPERATIONS

ACTIVITIES TIMES

OTS-IMMERSION 74h 33

ROV-IMMERSION 91h 43

STAND BY METEO 24h

NAVIGATION TIME 32h

WORK PREPARATION 16h

VISUAL INSPECTION 15h

DATA PROCESSING 20h


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Case Study: Inspection Scenario

ACTIVITIES TOT. DIVES TIMES

EVG & MPI 5 30h 49

FMD TEST 6 16h 7

ANODE MPC 10 44h 52

ACTIVITIES TOT. DIVES TIMES

PREP 9 14h 44

NDT 10 18h 19

ANODE EVR 13 19h 27

RISER EVR 7 12h 12

OTHERS 9 9h 51

ROV System

Diving Sistem


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Case Study: Repair Scenario

Project data

Characteristicas of pipeline

Diameter: 14

Nominalthickness: 11,13 mm Type of steel: X52 GRB

Platform descriptions

Platform A

Laying year: 1981

Depth: 103.5 m


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Clamp: Technical specification

Case Study: Damage and best solution

First leak:

Depth: 56 m53 m

Distance: 683m

Second leak:

Depth: 74 m43 m

Distance: 1050m

PROPERTY VALUE

Weight About 180 Kg

Clamp Dimension 14

Pins 1 3/8Key Opening 2 3/16

Torque 651 ft*lb


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Case Study: Summary of operations

Failure finding & checking by ROV

Dig in leak zone

Coating removal and cleaning ofthe pipeline

First breaks visual inspection


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Case Study: Summary of operations

Non Destructive Tests (NDT)

Clamp installation

Restoring the protectivecoating with epoxy resin

leak test @ 31bar positive


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Project Scope

Types of Inspection


Case Study

Conclusions

Agenda



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Conclusion

Life time extension 3/5 years

Reduced downtime

Avoid long and expensive repairs & interventions


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Acknowledgements

I would like to thank Eni E&P Division Management for

permission to present this work and related results

and MANUTcolleagues for the technical support and

needed assistance.


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Underwater Inspection Structure & Pipeline