spe-166589-ms presentation (final).ppt · spe-166589-ms • structural response monitoring of hunti...

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


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

Slide 3



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

Slide 4


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


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



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



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



HUNTINGTON HP RISER MONITORING SYSTEM

Slide 8


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)


MEASURED VS PREDICTED DATA COMPARISON

Fatigue predictions during intervention operation not conservative –accelerated fatigue damage!

Slide 9


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



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

Slide 10


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



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



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



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



Acknowledgements / Thank You / Questions

E.On E&P UK LtdClaxton

Pulse Structural Monitoring

Slide 14


spe-166589-ms presentation (final).ppt · spe-166589-ms • structural response monitoring of hunti...

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