Thsis - Feb 12 - Auk North 4th Well Metrology

7/27/2019 Thsis - Feb 12 - Auk North 4th Well Metrology

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THSIS - 29 Feb 2012

Presenters:

Pieter Jansen: Talisman-Energy (UK) Ltd

Greg Hammond Star Net Geomatics Ltd


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AUK North 4th Well Metrology

OVERVIEW

Project Requirements Existing Situation

Development of Offshore Execution Plan

Results

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Conclusions Future improvements


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Project Requirements

Execution of Laser Scan Survey of Auk North 4th

Well Manifold Installation of new Auk North 4th Well Manifold next to existing

Manifold

Installation of 8 inch spoolpiece connecting both Manifolds

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Note:

o Tight installation tolerances (70mm) due to short distance (12m) and relatively largediameter pipe (8 inch).

o No installation aids remaining on existing Manifold

o Tie-in Flange on existing Manifold covered by protection panel during metrologyoperations


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Auk North Existing, 4th Well Manifold & Tree Layout

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Auk North Existing, 4th Well Manifold & 8 Inch Spool Layout

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Auk North Existing Infrastructure

As-Built Information of Existing Manifoldo Existing Laser Scan XYZ Data Seto Dimensional Control Survey Report of Existing Manifold

o Metrology Report (Existing Manifold to the three Trees)

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Development of Project Execution Plan

Construction of Spheres and Scanner Tripod with focus ondeployment and recovery

Development of standalone BlueView system applicable for ROV& Diver deployment

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Development of Scanner and Target Sphere locations Introducing vertical control to the Data Set

Incorporating Processing Control, setting ground rules on how toprocess

Point Cloud acquisition / processing / QC Assessment of Offshore Personnel Requirements

Note:

o Weekly meetings commencing from the 23rdof August until the Mobilisation mid

December


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Construction of Spheres and Scanner Tripod with focus ondeployment and recovery operations

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Development of BlueView System

Development of standalone BlueView system applicable for ROV& Diver operation

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Development of Scanner Location Layout

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Development of Scanner Location Layout

Taking into account the: Geometry of Asset, Flange and Sphere layout

Behaviour of BlueView scanning returns

Minimum and maximum ran e of BlueView scanner

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Elevation of BlueView scanner in relationship to target


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Development of Target Sphere Location Layout

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Development of Target Sphere Location Layout

Taking into account the: Insonification of the Target Sphere by at least two BlueView

scanner positions

Geometry with the BlueView scanner positions and range in

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between Existing Infrastructure (can demand further Target Sphere

locations AND further BlueView scanner positions)

Terrain topography


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Introducing vertical control to the Data Set

Assigning a depth to each target sphere will provide a verticaldatum to counteract any warping of the model.

Additional depth control measures are in place; commonregistration objects include seabed sections which have a greater

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warp ng res r c on as e o ec s a p ane an no a s ng e po n


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Incorporating Processing Control

Identification of registration objects Assess weighting of each object

Checking data integrity of acquired point clouds

Data re istration of oint cloud subsets to re istration ob ects

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Network adjustment and review of parameters and registrationobjects to highlight problem areas within the data set

Check results against implemented benchmarks (e.g. acousticbaseline) to quality control scaling and rotational issues


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Offshore Personnel Requirements

24 hour operational cover 2 x Star Net Geomatics Processors

1 x BlueView Engineer

1 x Seatronics En ineer

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Results

BlueView Target Sphere representation

Effect on elevated position for scanner or target sphere

Effect of range to Target Sphere shape

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Results

Angle of object to BlueView scanner

Effect of striking angle of beam with object

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Results

How well does the BlueView scanner represent horizontal &vertical tubulars?

Vertical tubular comparison Vertical tubular with restricted diameter

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Results


Horizontal tubular comparison Horizontal tubular with restricted diameter

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Results


In numbers:Calculated

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Diameter [m]

Vertical tubular (Laser scan) 0.272

Vertical tubular (BlueView) free calc 0.327

Diameter enlargement 120%

Horizontal tubular (Laser scan) 0.507

Vertical tubular (BlueView) free calc 0.805

Diameter enlargement 159%


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Results

Difference of weighting to the overall result

Ref Registration

Spherical

Target

Weightin

g

Patch

Target

Weighting

Cylindrical

Target

Weighting

Total

Network

Error for

Enabled

Contraints

Flange to

Flange

(C) (Point

to Point

Dist)

Flange

Differenc

e (A - C)

C3-C8 (D)

(Point to

Point

Dist)

Transpond

er

Difference

(B - D)

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Acoustic Flange to Flange distance: 11.942m, Acoustic baseline: 29.393m

1

r g n a

Registration Weight 1 Weight 1 Weight 1 0.059 11.928 0.014 29.340 0.053

2

Ref 1 with

Patches

added to

structures Weight 1 Weight 1 Weight 1 0.065 11.937 0.005 29.347 0.046

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Ref 2 with

Weighting

Changed

Weight

0.9 Weight 1 Weight 0.5 0.088 11.941 0.001 29.376 0.017

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Ref 3 with

Digiquartz

level

introduced

Weight

0.9 Weight 1 Weight 0.5 0.067 11.944 -0.002 29.338 0.055


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Results

Comparison between laser scan and BlueView point clouds of theManifold top tubulars BlueView data set projects tubulars as long

Data set therefore appears to not conform to the Gauss distribution

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therefore always be long of the absolute length


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Results

Typical Acoustic Baseline Ranging Histogram

(Calculated Average = 10.366m, Acoustic Average = 10.353m)

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35

24

0

5

10

15

20

10.350

10.353

10.355

10.358

10.360

10.363

10.365

10.368

10.370

10.373

10.375

10.378

10.380

10.383

Range [m]

Frequency

Ranges


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Results

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Results

Existing Auk Manifold:

Angular Comparision

Top cord Cylinders Terrestrial Laser Survey (A) Blue View Survey (B) Difference (A-B)

Auk C1 - C4 89.951 89.685 0.266

- -

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. . .

Auk C3 - C2 89.957 90.353 -0.396

Auk C2 - C1 90.156 89.741 0.415

Distance Comparision

Top cord Cylinders Terrestrial Laser Survey (C) Blue View Survey (D) Difference (C-D)

Auk C4 - C2 (1) 5.571 5.596 -0.025

Auk C4 - C2 (2) 5.581 5.544 0.037

Auk C1 - C3 (1) 7.981 8.015 -0.034

Auk C1 - C3 (2) 7.975 8.010 -0.035


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Results

4th Well Manifold:

Angular Comparision

Top cord Cylinders Terrestrial Laser Survey (A) Blue View Survey (B) Difference (A-B)

MAN_09 - 11 90.162 90.049 0.113

- -

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_ . . .

MAN_13 - 15 89.825 89.773 0.052

MAN_15 - 09 90.07 90.044 0.026

Distance Comparision

Top cord Cylinders Terrestrial Laser Survey (C) Blue View Survey (D) Difference (C-D)

MAN_09 - 13 (1) 5.269 5.237 0.032

MAN_09 - 13 (2) 5.264 5.227 0.037

MAN_15 - 11 (1) 5.288 5.279 0.009

MAN_15 - 11 (2) 5.318 5.284 0.034


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Conclusions

BlueView / Star Net solution with scanner at three primarylocations inbetween the two manifolds have great correlation withLBL acoustic derived Flange to Flange position

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Registering objects and assign weighting to each class is thebasis for a sound network adjustment and final result. The finetuning will need to be perfected over time

Shorter BlueView ranges are more accurate, as the beam widthcasts greater footprints at longer distances.

Ranging comparison against known acoustic baseline is

invaluable


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Conclusions

Terrestrial laser scanning dramatically improves metrology

results. The model is best fitted within the BlueView point cloudhence providing additional accuracy detail (e.g. inclination offlanges)

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Operational execution time is dramatically reduced. Auk North 4th

well metrology took 8.5 hours (excluding bathy depth loops)

Longitudinal profile along spoolpiece route is a natural by-product of BlueView metrology

BlueView system meets the Measurement Accuracy required tosatisfy the Auk North 8 inch spool operational expansion budget(due to temperature and pressure) of 70mm


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Future Improvements:

Selective area scanning

Multiple ranging detection by (manually) setting of (time) gates

Narrowing of beam width to improve resolution

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Thsis - Feb 12 - Auk North 4th Well Metrology

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