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1 RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair January 28, 2014
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Page 1: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

1

RP 2MET: An API Recommended

Practice for Metocean

James Stear API Metocean RG Chair

January 28, 2014

Page 2: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

2

Presentation Overview

Purpose of 2MET Evolution of new document Layout and contents

– Core document – Informative annexes – Gulf annex and guidance

Ike near Gulf Coast, ISS

Page 3: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

3

RP 2MET Purpose

General requirements for developing metocean criteria – Determining conditions – Translating conditions into design

parameters

Clarify terms/definitions General guidance on regional

phenomena Common metocean reference for

all other RPs – Indicative criteria, use may be

allowed without metocean study for some 2A/2SIM/2SK applications

10 25 50 100 200 500 10006

8

10

12

14

16

18

2088-89-90 1000 m 1900-2008 (Weibull)

Hs

(m)

Return Period (years)

RP CDF Fit +2Sig 10 8.5 8.6 9.1 25 11.1 11.1 11.6 50 12.9 12.7 13.1 100 13.8 14.0 14.5 200 15.5 15.3 15.8 500 0.0 17.0 17.5 1000 0.0 18.1 18.6

DataFit k = 1.3Fit +/- 2 sigma

Page 4: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

4

Evolution of RP 2MET

RP 2A Section 2.3 (Last: 21st Edition, 2000)

Bulletin 2INT-MET (May 2007)

ISO 19901-1 (2005)

RP 2MET (2011-12)

ISO 19901-1/RP 2MET (2012-2013?)

2A:indicative Gulf shelf criteria since 1970’s; little metocean guidance

19901-1 first industry guidance document

2-INT-MET: hurricane guidance, revised 2A indicatives post IKR

2MET: home for all RP metocean, aligned with 19901-1

Page 5: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

5

Changes from 2A, 2-INT-MET to 2MET

General metocean study guidelines

Wave/current interaction from 2A, estimating extreme waves and crests

Wave spectra/spreading More Gulf study guidance,

indicatives: – Winter storms – Loop/eddy – TRWs

Page 6: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

6

RP 2MET Contents

Page 7: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

7

RP 2MET Core Document – Key Sections

Sections 3/4: Terms and definitions, symbols

Section 5: Guidance on determining parameters

Sections 6-10: General guidance/requirements on determining – Water level variations – Winds – Waves – Currents – Other metocean considerations

Maximum Sustained Wind (m/s), Hurricane Katrina

96oW 92oW 88oW 84oW 80oW 24oN

25oN

26oN

27oN

28oN

29oN

30oN

31oN

0

10

20

30

40

50

60

10 25 50 100 200 500 100020

25

30

35

40

45

50

55

60

6588-89-90 30 m 1950-2008 (Weibull)

WS

(m/s

)

Return Period (years)

RP CDF Fit +2Sig 10 28.0 28.8 30.4 25 35.9 35.4 37.0 50 40.3 40.1 41.7 100 44.1 44.7 46.3 200 0.0 49.1 50.8 500 0.0 54.9 56.6 1000 0.0 59.3 61.0

DataFit k = 1.1Fit +/- 2 sigma

Page 8: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

8

RP 2MET Core Document – Key Sections

Appendix A: more guidance on core topics – Wind profile, averaging, spectra

formulas – Wave periods, adjusting for

current, estimating heights, spectra, spreading factors and crests

– Current profile formulas

Appendix B: wave spectra formulas

Page 9: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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RP 2MET – Regional Annexes

Appendix C: regional information for various parts of the world, of different detail/quality

C.4: US Gulf of Mexico – Data sources available – Regional climatology – Water level, winds, waves,

currents overview – C.4.9: indicative metocean

parameters – C.4.10: guidance for Gulf

metocean studies

Page 10: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

10

Current Contents of Annex C.4: Gulf

Page 11: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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Hurricane Guidance

Guidance: – Use 50-100 year data

set, including through 2008

– Pool/track shift – Use synthetic/deductive

for long return periods Indicative:

– Three areas for “annual” conditions

– Central most severe

Comparing 2A, 2MET Indicative

Page 12: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

12

“Sudden” Hurricane Guidance

Guidance: – Develop using “watch

circle” approach, time of arrival of storm conditions appropriate to operation considered

Indicative: – One set for GOM,

representative of those storms bringing tropical storm-force winds to sites north of 28 N 24 hours after storm formation

Comparing 2A, 2MET Indicative

Page 13: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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Seasonal Hurricane Guidance

Guidance: – Can evaluate hazard as

pre- and post-peak periods – Should not base on single

months – Consider other hazards

(winter storm) outside of hurricane peak

Indicative: – Two sets provided,

West/Central and East, deepwater areas

– Early (May-July) and Late (October-November) season periods

Pre/Peak/Post 100-Year Ws, West/Central GOM

Page 14: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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Winter Storm Guidance

Guidance: – Important for operations,

especially October-March – Use measurements (NDBC

buoys), hindcasts as appropriate

– Include 1980’s – Highest observed ~ 9 m Hs

Indicative: – One set of conditions for

deepwater

1993 Storm of the Century

Page 15: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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Loop Current Guidance

Guidance: – Govern mooring design

for some facilities, and riser/tendon design

– Use historical record through 2008, caution with pre-1985 years

– Pool/site average – Consider joint Loop-

hurricane occurrence

Indicative: – Maximum surface

current case – Provided for 10- and

100-year

1.21.1

1.8

1.9 2.4 2.5 2.6

2.7 2.7

2.72.6

1.9

2.6

2.62.6

1.91.9

1.9 2.4

2.42.0

2.21.4

1.81.2

1.9 2.11.81.4

XOMCVXShellBP

98W 96W 94W 92W 90W 88W 86W 84W

98W 96W 94W 92W 90W 88W 86W 84W

26N

28N

30N

300 m

300 m

1.5 1.75 2.0 2.25 2.5 2.75

1.21.1

1.8

1.9 2.4 2.5 2.6

2.7 2.7

2.72.6

1.9

2.6

2.62.6

1.91.9

1.9 2.4

2.42.0

2.21.4

1.81.2

1.9 2.11.81.4

XOMCVXShellBP

98W 96W 94W 92W 90W 88W 86W 84W

98W 96W 94W 92W 90W 88W 86W 84W

26N

28N

30N

300 m

300 m

1.5 1.75 2.0 2.25 2.5 2.75

Profiles 175 cm/s

0.0 0.2 0.4 0.6 0.8 1.0Nondimensionalized Speed

600

400

200

0

Dep

th(m

)

Top: 100-Year Loop/Eddy Surface Speeds (m/sec)

Left: Normalized current profile

Page 16: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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Topographic Rossby Wave Guidance

Guidance: – TRW condition important for

risers and drilling operations along Sigsbee Escarpment

– Ability to model evolving, recommend 1-2 years of measurements at site

– May be correlated to Loop proximity

Indicative: – 10- and 100-year conditions

provided

Sigsbee Escarpment Area

Modeled Currents Cross-Slope

Page 17: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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Operational

Operational Hs-Tp – Data from NDBC 42001 – Set does not represent

extreme events

Wind roses for June, December – From 42001

Sea, air temperature ranges – From industry, NDBC

measurements

Page 18: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

US Gulf Annex Summary

Site-specific criteria is always preferred – annex values do not override a proper site-specific study

Select Gulf annex values may be used with 2A and 2SIM for depths less than 120 m, as mapped from L- and A- to appropriate return periods

May be used with 2SK for low consequence operations

New values yield generally loads > older 2A, Section 17, and > new site-specific

Page 19: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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C.4

C.6

C.6

C.6

C.6

C.5

C.5

Other US Waters

California coast unchanged from ISO 19901-1 (C.5)

Other US waters are “legacy” RP 2A (need update) – may not be used for design

Page 20: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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RP 2MET Status

Passed second ballot June 2013

API preparing for publication 2014

Page 21: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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2MET Development Team

Support from: – API SC2 members – Industry and regulatory reviewers – MODU JIP – CASE JIP – DeepStar JIP

RG1 Members: – Cort Cooper, Chevron – Markku Santala, Chevron – James Stear, Chevron – Gene Berek, XOM – Doug Mitchell, XOM – Dave Driver, BP – Mike Vogel, Shell – Jason McConochie, Shell – Dave Peters, ConocoPhillips – Chris Yetsko, ConocoPhillips – Gail Baxter, Marathon – George Forristall, FOE – John Heideman – Skip Ward – Don Resio – Gabriel Toro

Page 22: RP 2MET: An API Recommended Practice for Metocean · RP 2MET: An API Recommended Practice for Metocean James Stear API Metocean RG Chair . January 28, 2014 . 2 Presentation Overview

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Thanks

Any questions?

Hurricane Ike from ISS, 2008


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