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SWIMMERSWIMMERSSubseaubsea

WWorkork

IInspection &nspection &

MMaintenance withaintenance with

MMinimuminimum

EEnvironmentnvironment

RRovov

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Presentation Overview

Limitations of ROV operations on deepwater fields

The hybrid ROV / AUV solution System components and mode of

operation

Sea Trials

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Project Partners

Project supported by the European Commission (THERMIE Programme)

•Approach Sonar System

•Long Range Positioning System

•Acoustic Communications

•Technical Advisory

•General Advisory

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ROV operation indeep water fields - Drawbacks :

Permanent surface support (DP Vessel) Significant cost

90% of the total spread cost (typically) Availability

Time for mobilisation Weather conditions

Umbilical / Tether management Increasing size / length of umbilicals Low Reliability of associated components (slip rings,

connectors…) - 85% of break downs

… Is it possible to avoid this ?

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Deepwater FieldSubsea Installations

Statement : Subsea facilities are linked to the surface production unit by a Production Umbilical

The basic idea is to :

Tap the ROV power and data communication from the sub-sea facilities through the production umbilical

Operate the ROV from the surface production facilities

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The SWIMMER Solution :An Hybrid ROV / AUV

AUV Shuttle for flying a standard ROV from surface to sub-sea facilities

– No surface / vehicle physical link during transit phase

– Uses simple permanent sub-sea installation Docking station connected to production umbilical

– No limitation on ROV tasks Real-time controlled and powered up from the surface

through production umbilical

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The Swimmer shuttle :The Swimmer shuttle :

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Sea TrialsSea Trials

Video

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Long Range Positioning System& Acoustic Communication

Hybrid LBL / Dead Reckoning Long Range Positioning System On-board absolute position calculation Metric accuracy Solves multiple path problems Vehicle motion compensation

Bi-directional Acoustic Telemetry Link 20 bits/s data rate Half duplex

1 acoustic system : 10 km slant range Ultra-high reliability and

noise immunity Use CHIRP modulation

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Acoustic Modules Lay out

FPSO

Docking S ta tion#1

W ell-Head

Manifold

Docking S ta tion#2

(ta rge t)

Docking S ta tion#3

M x

AUV(M 1)

M x

M 2

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Short Range Positioning System

Approach on Docking Station requires : Decimetric accuracy

100 m range

No active system on the Docking Station

On-board SONAR image 3D processing : Uses 2 profiling sonars Accuracy increases as distance to

target decreases Positioning data refresh rate : 1 Hz

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Short Range Positioning System :SONAR Image 3D-Processing

Dock ing S tationCAD Model

S O NAR S im ula tor(S oftw a re )

AUV's Pos it.Estimation

SONARParameters

S O NAR P roce ssorSONAR Heads

VirtualImage

RealImage

Com pa reIm a ge s

RelativePos ition

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ConclusionsConclusions

• By achieving a first fully automatic docking operation of Swimmer on its station (October 2001), the feasibility of Hybrid vehicles has been demonstrated.

• Intense R&D efforts still have to be deployed to reach an operational stage (up to 2005 ?).