NASNet Operational Experience - THS · NASNet Operational Experience FRADE Project, ... The water depth at the FPSO is 1000 meters to 1400 at ... Lessons Learnt

seabed-to-surface

NASNet Operational ExperienceFRADE Project, BrazilHydrographic Society in Scotland

23rd April 2009

29 April 2009slide 2

seabed-to-surfaceprivate and confidential

North America and Mexico (NAMEX)

Regional Profile

Operating in the Gulf of Mexico and the Caribbean, undertaking a range of construction and installation engineering services.

NAMEX divides its current business into 3 principal areas of operation:

Subsea Umbilical Risers and Flowlines (SURF)

Inspection and Maintenance and Repair (IMR)

Conventional Field Development and Trunk lines

The NAMEX region is focused on and ready for deepwater SURF projects and IMR



Frade ProjectCampos Basin Brasil



DTM Brazilian Continental Shelf

FRADE



Frade field developmentThe Frade field is 6 Km x 4 KmThe water depth at the FPSO is 1000 meters to 1400 at the East extent of the field 8” Gas I/E Pipeline from the FPSO to termination 41Km SW in water depth 130 meters – PRA1 PLEM –Acergy Installed

The development consists of :22 Riser Anchor Piles17 Production Flow Lines9 Gas Lift Lines10 Water Injection Lines 17 UmbilicalsFlexible Jumpers, Flying leads



Frade Develpoment field layout



Typical well site



LBL RequirementsProvide LBL coverage over the entire construction area with an relative accuracy of <2 meters and 0.5 meters RMSCapacity to operate on the seabed for the entire construction period and beyond without recovering for battery changesPotential to accommodate multi vessel users (SIMOPS)Straightforward to deploy and manage

System ConsiderationsCostReliabilityMethodSupport



NASNet

Advantage - Disadvantage

Fewer stations to deploy and calibrate – savings in vessel time

Reduced calibration time –savings in vessel time

Simplified array management

Reduced O/P power levels –Longevity of operating time with Lithium battery packs

Quicker update rate of position

New and untried technology with no commercial experience

Vessel modifications required to operate the NASNet system

Software routines needed to be changed to make the system more effective

Additional training of personnel to operate the system



Original Proposal

System uses Acoustic Spread Spectrum TechnologyOperating principle is similar to GPS in that each station transmits information on a regular basisSignal includes accurate time, error correction and station informationUnlike Transponder systems where an interrogation signal has to be transmitted, NASNet receivers only have to listen



NASNet 8 Station Array

WE LL C

3TXCO3DB

4TXCO2D

OUS2

GT-203A

3RJS416

1RJS366

WELL C

MUS2

GT-220

N5I1

N5P1

ODI1

MDI1

OUI1

MUI2

MUI1

OUI2

MDP1MDP2

MUP4

ODP1

OUP1

OUP3

OUP2

MUP2

MUP1

MUP3

ODP3(NOTE 3)



NASNet Mini Station



NASNet Field proposed with 16 stations



Acoustic Challenges

SVPPositive going sound velocity close to the seabed causing the acoustic signal to bend towards the surface

TopographyThough the construction area has no great features there is a general slope from West to East of 3 ° with slope increasing in areas of the water injection loop to 5 °-Because of this we get ground absorption up slope and the signal bending away down slope.



Acoustic Analysis Predicted cover 28 Stations



Acoustic Analysis – Predicted cover 22 Stations



NASNet 22 Station Array with 6 Optional



Frade ProjectInitial DeploymentThe initial deployment was 8 stations to enable installation of the Riser Anchor Piles around the FPSO location.



Frade ProjectInitial DeploymentThe initial deployment was 8 stations to enable installation of the Riser Anchor Piles around the FPSO location.Each deployment and calibration was completed in 3 hours.



Frade ProjectInitial DeploymentThe initial deployment was 8 stations to enable installation of the Riser Anchor Piles around the FPSO location.Each deployment and calibration was completed in 3 hours.Position check after calibration on an existing wellhead



Frade ProjectInitial DeploymentThe initial deployment was 8 stations to enable installation of the Riser Anchor Piles around the FPSO location.Each deployment and calibration was completed in 3 hours.Position check after calibration on an existing wellheadSet a construction receiver on the seabed in the center of the array to monitor the integrity of the array



Frade ProjectInitial Deployment

The initial deployment was 8 stations to enable installation of the Riser Anchor Piles around the FPSO location

Each deployment and calibration was completed in 3 hours

Position check after calibration on an existing wellhead

Set a construction receiver on the seabed in the center of the array to monitor the integrity of the array

Results of the calibration and confidence check



Eight Beacon Array Calibration and Confidence Check

Object Easting Northing Range3TXC03DB 412772.00 7579292.00NASnet 412764.16 7579294.75

Heading098 412766.23 7579294.59188 412764.86 7579294.10278 412764.59 7579296.77008 412766.32 7579294.38

Med 412765.55 7579294.49Max 412766.32 7579296.77Min 412764.59 7579294.10Rng 1.73 2.67Std 0.90 1.22

Diff. -1.39 0.27

Well Diff. 7.84 -2.75 8.31 NASnetWell Diff. 6.46 0.27 6.46 HIPAP



Pre Lay Survey

Deployment of the remaining Stations to complete the 22 station array

Box in Calibration of the remaining stations

Installed two additional Construction receivers across the field

Conducted Pre lay survey of the Frade Development area

Logged NASNet coverage over all the flow line routes and Well locations

Checked the positions of the four existing wells



NASNet Installation - Normand Mermaid

NASNet Surface Controller Gate Valve and Hoist



Installation Diagram



Deployment - 7 Meters above seabed



Construction Receiver on a modified MS Stand



MS Station Deployed Subsea



Existing WellsAUV-NASNet-SSBL

2.8311.533.62513.725Difference

7578109.2413943.57578108.4413941.375781124139554TXC02D

-3.826.24-2.597.51Difference

7579294.49412765.557579294.75412764.167579292.00412772.003TXCO3DB

-2.12-0.42-2.35-1.71Difference

7578926.12415641.427578926.35415642.7275789244156413RJS416

2.50-5.093.48-5.38Difference

7580613.5412979.17580612.5412979.475806164129741RJS366

NorthingEastingNorthingEastingNorthingEasting

HIPAPNASNetAUV SurveyWell #



Tracking comparison HiPAP USBL/NASNet



NASNet Position Solution CRx and ROV



Conclusions: System and Project Evaluation Summary

Robust and stable positioning meeting specification expectations

Uniform positioning regime over entire field

Highly acceptable cycle time

Simultaneous users – True multi user system

Improving / growing technical support

Improving system technical reliability

Joint planning and preparation is “a must”

Difficult to establish multi user operating responsibilities unless managed by Client



Lessons LearntPlanning

Seabed Topography and Velocity analysis

TrainingOperator level & higher understanding of acoustic principles

Support Develop a support & communications structure for remote operations

TechnicalSeabed stability, moorings etcVessel preparationDealing with technical difficulties in a structured and constructive mannerSimOps need some degree of management

CommercialHanding over of network, client understanding.Acceptance and expectations of other usersClient free issue? – contractual concerns



Relaxation Time

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NASNet Operational Experience - THS · NASNet Operational Experience FRADE Project, ... The water depth at the FPSO is 1000 meters to 1400 at ... Lessons Learnt