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SPE-166589-MSStructural Response Monitoring Of Huntington
HP Drilling And Completion Riser
A. Rimmer, B. Bamra, 2H Offshore Engineering Ltd, R. M. Allan, SPE, G. Proud, S. Davidson, E.ON E&P UK Ltd., B. Parker, Pulse Structural
Monitoring Ltd
Learn more at www.2hoffshore.com
OUTLINE
Background
HP system design challenge
HP riser system description
Reasons for monitoring – Riser analysis outcomes
Riser monitoring system
Measured data vs predictions
Lessons learnt
Summary and Conclusions
Slide 2
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
BACKGROUND
Increased use of HP risers to drill and complete subsea wells from jackup rigs:• Deeper water depths (>>70m)• More challenging locations and environments• Longer duration of operations
Increased requirement to collect in-situ data to:• Confirm riser design acceptable• Calibrate analysis models• Confirm riser integrity through operations
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SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
HUNTINGTON HP RISER DESCRIPTION
Block 22/14b of North Sea
“Deep” 91m water depth
Heavy duty jackup MODU
Harsh environment
24inch OD, 1.5inch wall HP riser
18 ¾” surface BOP
350Te Tensioning System
18 ¾” subsea housing
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SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Rotarty Table
Diverter
Top of Overshot MandrelOvershot PackerOvershot Mandrel (18 3/4" 10K API Flange Down)
18 3/4" 10K Annular BOP
18 3/4" 15K Hydril BOPDouble Studded Adapter
CTU Deck CTU
Bottom of Jackup hull (Air Gap 20.397m)
80ksi Tension Joint65ksi Pup joint type 2
65ksi Pup joint type 1MSL
65ksi Riser Intermediate Joints
80ksi Riser Standard Joint
80ksi Lower Stress JointWellhead Connector
Wellhead
Mudline Template
30 x 1.75" Conductor
30 x 1.75" to 30 x 1 " Crossover Joint
30 x 1 " Conductor Joints
Drilling Mode Riser Stackup
Tension Ring
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HP RISER DESIGN CHALLENGE
Detailed analysis required to confirm:• Tensioning requirements • Design code acceptance• Operating guidance
Detailed analysis challenges:• Predictions of marginal performance• Conservative approach?• Effect of assumptions?• Limitations of our knowledge?• Safety margin understood?
Slide 5
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
DETAILED RISER ANALYSIS OUTCOMES
Acceptance of HP riser and operating guidance to be developed for:• Strength (up to 50year storm)• Wave fatigue (>1year design life)• Vortex induced vibration fatigue (>1year design life)• Operating & Installation envelopes
Key challenges to Huntington HP riser:• High CTU deck loads – lateral & vertical• High stresses in tension / stress joint• Acceptance only achieved through:
• Design change• Reduced analysis conservatism• Careful management of tension based on weather forecast
(fatigue vs extreme loads trade-off)• Careful management of pressure based on weather forecast
Slide 6
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
WHY MONITOR AT HUNTINGTON?
A number of integrity threats from riser analysis and risk assessment identified:• CTU deck loads• Tension joint loads• CTU failure• Rig settlement• Fatigue
Assumptions in the analysis = uncertain safety margin
Long duration of operations
Monitoring to verify analysis & confirm loads/deflections/fatigue within safe limits
Slide 7
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
HUNTINGTON HP RISER MONITORING SYSTEM
Slide 8
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Tension Joint EEXD box (3 axis accelerometer + 2 axis angular rate)
Tension Joint Strain Stick
CTU Deck EEXD box (3 axis accelerometer, CTU cylinder pressures)
Wave Radar
Central Control Console (with Communication link to shore)
Wave Radar
Acoustic Doppler Current Profiler
Jackup (3 axis accelerometer)
Learn more at www.2hoffshore.com
MEASURED VS PREDICTED DATA COMPARISON
Fatigue predictions during intervention operation not conservative –accelerated fatigue damage!
Slide 9
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
0
1
2
3
4
5
6
7
8
0.0E+00
5.0E-07
1.0E-06
1.5E-06
2.0E-06
2.5E-06
3.0E-06
3.5E-06
4.0E-06
14 Feb 00:00 16 Feb 00:00 18 Feb 00:00 20 Feb 00:00 22 Feb 00:00 24 Feb 00:00 26 Feb 00:00
Sign
ific
ant
Wav
e H
eigh
t, H
s (m
)
Cu
mul
ativ
e D
amag
e
Event Timeline
Huntington HP RiserCUMULATIVE FATIGUE DAMAGE
Upper Riser, February 2012
Maximum Measured Fatigue Damage Maximum Predicted Fatigue Damage Significant Wave Height
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MEASURED VS PREDICTED DATA COMPARISON
Why?• Other fatigue sources • Jackup motion assumption• Other modelling assumptions• Model doesn’t include
intervention riser string or coiled tubing
Difficult to calibrate model for all conditions & due to data scatter• Apply calibration factor
Fatigue design limits not exceeded
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SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
0.00
0.05
0.10
0.15
0.20
0.25
0 1 2 3 4 5 6 7 8
Dis
plac
emen
t (m
)
Significant Wave Height, Hs (m)
Huntington HP RiserMAXIMUM MEASURED AND MODELLED JACKUP DISPLACEMENT
CTU Deck, February 2012
Maximum Measured Displacement Modelled Displacement
0
1
2
3
4
5
6
7
8
0.0E+00
2.0E-08
4.0E-08
6.0E-08
8.0E-08
1.0E-07
1.2E-07
1.4E-07
1.6E-07
1.8E-07
14-Feb 00:00 16-Feb 00:00 18-Feb 00:00 20-Feb 00:00 22-Feb 00:00 24-Feb 00:00 26-Feb 00:00
Sign
ific
ant
Wav
e H
eigh
t, H
s (m
)
Dam
age
Event Timeline
Huntington HP RiserFATIGUE DAMAGE PER EVENT
Upper Riser, February 2012
Measured Predicted Significant Wave Height
High damage at start / end of coiled tubing operation
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MEASURED VS PREDICTED DATA COMPARISON
The monitoring equipment therefore:• Demonstrated equipment operated within design limits• Provided estimates of the residual design fatigue
Based on this information the operator can make informed decisions :• Can riser continue to be operated safely• Do critical joints in the system need inspecting• Do critical joints in the system need replacing• Is increased/reduced frequency of monitoring data review required
Usage of the riser can be better managed to ensure integrity and safe operation.
Slide 11
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
LESSONS LEARNED
• Extreme response difficult to verify.• The ADCP should be installed away from the jackup leg - interference
when the ADCP is blown next to the leg.• The drilling report should be used to tie rig events into monitoring
data.• Full current and wave information should be obtained to allow
accurate analysis calibration, with directions measured and in the case of wave, the surface elevation timetrace recorded.
• Improved and more direct measurements of stroke and lateral loading (from strain) would improve accuracy of measurements.
• Results inferred from the analysis should be minimized to ensure a robust calibration factor between the model and measured data.
Slide 12
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
SUMMARY AND CONCLUSIONS
• Detailed riser analysis vital as part of planning process for offshore operations.
• Can be difficult to quantify safety margin – conservative approach to analysis and design adopted.
• Monitoring system deployed at Huntington to quantify safety margin and manage risks.
• Data collected highlighted that analysis can be under-conservative, but confirmed riser operated within design limits.
• Calibration of fatigue predictions possible using a “calibration factor”.• Use of the real time monitoring system allows the fatigue usage of the
system to be more actively managed.• Extreme response of the system is difficult to verify.• Further development of the system in progress (software &
hardware).
Slide 13
SPE-166589-MS • Structural Response Monitoring Of Huntington HP Drilling And Completion Riser• Balraj Bamra
Learn more at www.2hoffshore.com
Acknowledgements / Thank You / Questions
E.On E&P UK LtdClaxton
Pulse Structural Monitoring
Slide 14
Learn more at www.2hoffshore.com