AUK North 4 Well Metrology - ths.org.uk · AUK North 4 th Well Metrology Results Existing Auk Manifold: Angular Comparision Top cord Cylinders Terrestrial Laser Survey (A) Blue View

AUK North 4th Well MetrologyAUK North 4th Well Metrology

THSIS - 29 Feb 2012

Presenters:

Pieter Jansen: Talisman-Energy (UK) Ltd

Greg Hammond Star Net Geomatics Ltd

AUK North 4th Well Metrology

OVERVIEW

• Project Requirements

• Existing Situation

• Development of Offshore Execution Plan

• Results

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• Results

• Conclusions

• Future improvements


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 large

diameter pipe (8 inch).

o No installation aids remaining on existing Manifold

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

operations


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 Set

o Dimensional Control Survey Report of Existing Manifold

o Metrology Report (Existing Manifold to the three Trees)

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<Show terrestrial data set>


Development of Project Execution Plan

• Construction of Spheres and Scanner Tripod with focus on deployment and recovery

• Development of standalone BlueView system applicable for ROV & Diver deployment

• Development of Scanner and Target Sphere locations

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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 to process

• Point Cloud acquisition / processing / QC

• Assessment of Offshore Personnel Requirements

Note:

o Weekly meetings commencing from the 23rd of August until the Mobilisation mid

December


Construction of Spheres and Scanner Tripod with focus on

deployment 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 range of BlueView scanner

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• Minimum and maximum range of BlueView scanner

• Elevation of BlueView scanner in relationship to target


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 between

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between

• Existing Infrastructure (can demand further Target Sphere locations AND further BlueView scanner positions)

• Terrain topography


Introducing vertical control to the Data Set

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

• Additional depth control measures are in place; common registration objects include seabed sections which have a greater ‘warping’ restriction as the object is a plane and not a single point

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‘warping’ restriction as the object is a plane and not a single point


Incorporating Processing Control

• Identification of registration objects <show>

• Assess weighting of each object

• Checking data integrity of acquired point clouds

• Data registration of point cloud subsets to registration objects

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• Data registration of point cloud subsets to registration objects

• Network adjustment and review of parameters and registration objects to highlight problem areas within the data set

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


Offshore Personnel Requirements

• 24 hour operational cover

• 2 x Star Net Geomatics Processors

• 1 x BlueView Engineer

• 1 x Seatronics Engineer

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• 1 x Seatronics Engineer


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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<show>


Results

• Angle of object to BlueView scanner

− Effect of striking angle of beam with object

<show>

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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

• How well does the BlueView scanner represent horizontal & vertical tubulars? <continued>

Horizontal tubular comparison Horizontal tubular with restricted diameter

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Results

• How well does the BlueView scanner represent horizontal & vertical tubulars? <continued>

In numbers:

DescriptionCalculated

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DescriptionCalculated

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%


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)

Original

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

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Original

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

4

Ref 3 with

Digiquartz

level

introduced

Weight

0.9 Weight 1 Weight 0.5 0.067 11.944 -0.002 29.338 0.055


Results

• Comparison between laser scan and BlueView point clouds of the Manifold top tubulars

− BlueView data set projects tubulars as long

− Data set therefore appears to not conform to the Gauss distribution

− Any distance based on an average (as provided by any network adjustment) will

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− Any distance based on an average (as provided by any network adjustment) will

therefore always be long of the absolute length


Results

Typical Acoustic Baseline Ranging Histogram

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

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30

35

24

0

5

10

15

20

25

10.3

5010

.353

10.3

5510

.358

10.3

6010

.363

10.3

6510

.368

10.3

7010

.373

10.3

7510

.378

10.3

8010

.383

Range [m]

Fre

qu

en

cy

Ranges


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

Auk C4 - C3 89.937 90.220 -0.283

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Auk C4 - C3 89.937 90.220 -0.283

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


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

MAN_11 - 13 89.942 90.134 -0.192

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MAN_11 - 13 89.942 90.134 -0.192

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


Conclusions

• BlueView / Star Net solution with scanner at three primary locations inbetween the two manifolds have great correlation with LBL acoustic derived Flange to Flange position

• Registering objects and assign weighting to each class is the

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• Registering objects and assign weighting to each class is the basis for a sound network adjustment and final result. The fine tuning will need to be perfected over time

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

• Ranging comparison against known acoustic baseline is invaluable


Conclusions

• Terrestrial laser scanning dramatically improves metrology results. The model is best fitted within the BlueView point cloud hence providing additional accuracy detail (e.g. inclination of flanges) <show>

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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 to satisfy the Auk North 8 inch spool operational expansion budget (due to temperature and pressure) of 70mm


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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Questions?

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Questions?

Documents

AUK North 4 Well Metrology - ths.org.uk · AUK North 4 th Well Metrology Results Existing Auk Manifold: Angular Comparision Top cord Cylinders Terrestrial Laser Survey (A) Blue View