Petrobras P-36Incident

Susana Leon Caceres

Master’s Student in Safety Engineering

Mary Kay O’Connor Process Safety Center

Texas A&M University, College Station.

January 14th , 2016

Steering Committee Meeting

Susana Leon Caceres• I was born and raised in Bucaramanga, Colombia

• Bachelor’s degree in Chemical Engineering at “Universidad Industrial de Santander”

• Safety Engineer at Ecopetrol in Cartagena’s Refinery

• Master’s Student in Safety Engineering at Texas A&M University (First Year)

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Source: Google maps[1]

Outline

• Background

• Petrobras P-36 incident description

• Sequence of events

• Investigation-what went wrong?

• Causes and root causes

• Conclusions and recommendations

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Floating Production Unit (FPU) Background

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• Original name: “Spirit of Columbus”

• Designed and constructed in 1984-1994 in Italy

• Original intent: oil drilling and small production unit [3]

• Contracted by Petrobras in 1996, and renamed to P-36

• Adapted into a large oil production platform (FPU) by Canadian Shipyard Davie Industry[3]

• Major changes:

Designed to operate at 500 m water depth adapted to 1360 m [4,5]

Capacity 180,000 bpd of oil and 7.2 million m3/day of gas

Installed buoyancy boxes to accommodate extra weight of topsides

Average production on March 15: 84,000 bpd of oil and 1.3 millions m3/day gas [4,5]

• Installed at the Roncador Field in 2000

Fig 1. Location of Campos Basin’s Rocandor field [1,2]

Accident Description [6, 7]

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When – 15th March, 2001

Where – Roncador field in Campos Basin, 125 km from the coast of Brazil

2 explosions in one of the support legs, followed by flooding of the leg

The FPU sank (on March 20th)

Consequences

• 11 fatalities

• Financial losses nearing 1 billion dollars

• Around 316,000 gal of diesel and 80,000 gal of crude oil spilled

Fig 2. P-36 platformsinking [8]

Fig 3. P-36 spill on the sea [9]

Accident Description

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Aft

D

C

B

Fire pumps (seawater pumps): A: Portside aftB: Portside foreC: Starboard foreD: Starboard aft

Fig 4. General view of P-36 [6] Fig 5. Semi-submersible platform modelAdapted from [10]

Platform Layout “Aerial view” [6,12]

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Starbo

ard

Aft

Portsid

e

Bow/Fore

Fire pumps: A: Portside aftB: Portside foreC: Starboard foreD: Starboard aft

A

BC

D

Emergency Drain TankFig 6. Emergency Drain Tank , Top view.Source: The Accident of P-36 FPS [6].

Fig 7. Special drawings created,

Platform aerial view.Source: Accident

Investigation Petrobras P-36 Sinking

(DNV) [12].

Sequence of events (March 10th - 20th, 2001 )[4,6]

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Causes

Incident day Salvage operations

Fig 7. Adapted general timeline of the P-36 accident.Source: Petrobras and Brazilian navy reports [4,6].

Sequence of events (March 15th)[4,6]

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• First explosion (Mechanical explosion – pressure burst)― Due to pressure build-up in a drain tank

• Second explosion(Chemical explosion)― Due to ignition of released vapors

• Fire alarm system operations

Fig 8. Inclination six degreesSource: Acidente da P-36 –Explosao e Naufragio [11]

Investigation –what went wrong? [4,6,12]

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OPEN

CLOSE

Partially Close

HEADERVALVE

PRODUCTION HEADER

PORTEDT

STARBOARDEDT

BLIND FLANGE

ATMOSPHERICVENT

CAISSONVALVE

10 bar

Aft/Fore viewInitial conditions [4,6,12]

• Both tanks contained 50% of water• The pump of the Starboard-aft Emergency Drain Tank was removed for maintenance• 3 valves were closed and properly isolated with blind flanges• 1 valve was manually closed but no blind flange was installed(allowing liquid to enter)

Fig 9. Flow chart Emergency Drain tank system on the aft site (initial conditions on March 14th).Source: Adapted from [4,7,11,12]

BLIND FLANGE

Investigation –what went wrong? [4,6,12]

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HEADERVALVE

PRODUCTION HEADER

PORTEMERGENCYDRAIN TANK

ATMOSPHERICVENT

CAISSONVALVE

10 bar

Aft/Fore viewEmptying portside TDE [4,6]

• Port pump aligned towards the production header

• Outflow line valves (starboard) opened

• Delay to start up the drain pump of the port aft TDE

• Reverse flow during 54 min The

pressure started

increasing

STARBOARD EMERGENCYDRAIN TANK

Valve leaks

Fig 10. Flow chart Emergency Drain tank system on the aft site (unsuccessful activation of the port tank pump).Source: Adapted from [4,7,11,12]

OPEN

CLOSE

Partially Close

BLIND FLANGE

BLIND FLANGE

VA

PO

RO

ILW

ATE

R

Investigation –what went wrong? [6,11]

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HEADERVALVE

PRODUCTION HEADER

ATMOSPHERICVENT

CAISSON VALVE

10 bar

Aft/Fore view

Internal pressure reaches 10 bar

P (

bar

)

Min

ute

s

STARBOARD EMERGENCYDRAIN TANK

Water started

pumping out

19 barCapacity

Valve leaks

Fig 11. Flow chart Emergency Drain tank system on the aft site (Port tank pump start up).Source: Adapted from [4,7,11,12]

PORT EMERGENCYDRAIN TANK

OPEN

CLOSE

Partially Close

BLIND FLANGE

BLIND FLANGE

Investigation –what went wrong ? [6,11]

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Tank’s wall Rupture (Leakage) Tank’s wall Rupture (Gas Dispersion) Flooding in 4th Level (Oil and Water)

Fig 12. Adapted From Acidente da P-36 –Explosao e Naufragio.Source: Acidente da P-36 –Explosao e Naufragio (Petrobras – 15.03.2001)

.

3RD LEVEL 3RD LEVEL 3RD LEVEL

4th LEVEL 4th LEVEL 4th LEVEL

Investigation –what went wrong ? [6,12]

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• The fire alarm system was activated and the starboard pump was automatically started .

•Water reached the ventilation duct rupture, and filled the pump room (pontoon).

• Manholes connecting the pontoon with the stability box and ballast tanks were opened for inspection. Fig 13. Starboard aft column.

Source: Accident Investigation Petrobras P-36 Sinking (DNV) [12].

Cause and effect – (Fishbone) [4,6,7]

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Causes [4,6]

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Explosion

• Absence of a blind flange in the intake valve on the starboard aft tank

• The port pump was aligned towards production header, instead of caisson production.

Unit Sinking

• Failure of the ventilation system- watertight dampers actuators

• Manholes opened on the ballast tank and stability box

• Lack of training in emergency stability control

• Design of the sea-chest valve (fail mode)

Conclusions

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• Investigation results indicate that the most likely scenario was

overpressure in the starboard aft emergency drain tank, which caused

a mechanical explosion and lead to the rupture of the tank. This initial

event allowed the release of flammable hydrocarbon gas, which

eventually originated a second explosion.

• It was concluded that the main cause of these events was failure to

provide effective isolation in the intake valve at the starboard aft tank

during maintenance (i.e., absence of blind flange), which allowed

unexpected reverse oil and gas flow into the starboard aft tank.

Conclusions

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• Although there were many factors that contributed to the flooding

process of the unit. However, this process was accelerated because of

the fail mode / fail state of the sea-chest valves and because several

buoyancy boxes were open at the same time for inspection and thus

when water entered they flooded.

Recommendations [4,6,14]

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Petrobras Inquiry Commission

• Improve offshore operations and enhance safety on board offshore units.

• Do not install pressure vessels and atmospheric tanks connected to the production

process facilities (i.e. hydrocarbons) inside columns or pontoons: Re-assess the risk and

review the design of the units that operate with these design issues.

Brazilian Governmental Petroleum Agency (ANP) & Brazilian Port Administration

(DPC)

• Review the criteria for a number of simultaneous work permits in offshore activities.

• Review the content of the current contingency plans.

Key Recommendation: Creation of the Operational Excellence Program – PEO

Engineering design/ Safety/ Ballast and Stability/ Maintenance/ Operation/ Human Resources

Recommendation

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Budget cutting – needs Risk Based review

Understand impacts of cuts in budgets in important areas such as

SAFETY and QUALITY

References

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1. Google Map 2016 [cite 2016 01/11]; Available from: https://www.google.it/maps/place/Colombia/@4.18406,-77.4395073,6z/data=!3m1!4b1!4m2!3m1!1s0x8e15a43aae1594a3:0x9a0d9a04eff2a340

2. Noticias Internacionais – International Oil and Gas News 2014 [cite 2016 01/11]; Available from:http://blogonip.blogspot.com/2014_07_16_archive.html

3. Mogensen, V., Worker Safety under Siege: Labor, Capital, and the Politics of Workplace Safety in a Deregulated World. ILR Review, 2008.61(2): p. 82.

4. (ANP), B.G.P.A.-. and B.P.A.-. (DPC), CASUALTY OF PLATFORM "P-36". 2001: p. 29.5. Henriques, C. and M. Fachetti. Roncador Field: Transport of P-36 and Installation of the Mooring System. in Offshore Technology Conference.

2000. Offshore Technology Conference.6. Barusco, P. The accident of P-36 FPS. in Offshore Technology Conference. 2002. Offshore Technology Conference.7. Whelan, S., Petrobras P-36 Accident. Proto-Type, 2013. 1.8. Mail Online 2010 [cite 2016 01/11]; Available from: http://www.dailymail.co.uk/home/moslive/article-1328470/Britains-latest-offshore-

investment-The-Brazilian-oil-boom.html9. Gulf Oil Disaster with enormous oil plume as much as 300 feet thick in place-from Deepwater Horizon crude oil drilling accident 2010 [cite

2016 01/11]; Available from: https://cricketdiane.wordpress.com/tag/oil-spill-in-gulf-of-mexico/10. Keel 2016 [cite 2016 01/11]; Available from: http://keelsolution.com/project/semi-submersible/#11. Acidente da P-36 –Explosao e Naufragio (Petrobras – 15.03.2001). 2015 [cite 2016 01/11]; Available from <

https://www.youtube.com/watch?v=Oz10Rsw_bJc>12. Pitblado, R., Accident Investigation Petrobras P-36 Sinking 2001.13. Videiro, P.M., et al. The Accident of the P-36 Platform: The Rupture of the Emergency Drainage Tank. in ASME 2002 21st International

Conference on Offshore Mechanics and Arctic Engineering. 2002. American Society of Mechanical Engineers.14. da Costa Fraga, C.T. and C.F. Mastrangelo, Petrobras Operational Excellence Programme. paper, 2002. 28605: p. 24-27.15. Berends, W.R., $PRICE AND PROFIT %, The Essential Guide to Product and Service Pricing and Profit Forecasting. 2004. p. 6116. Hancock, C., M. Jarvis, and N. Vineall, PETROLEO BRASILEIRO SA (“PETROBRAS”) Appellant - and - PETROMEC INC Respondent. 2012.

Acknowledgement • Dr. Sam Mannan

• Dr. Clementina Ramirez

• Dr. Robin Pitblado

• Mr. Jim Pettigrew

• Ms. Valerie Green

• Wen Zhu

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• Logan Hatanaka

• Zohra Halim

• Tatiana Flechas

• All members of SC

• All members of MKOPSC

Thank you!

Questions?

January 14th, 2016

Steering Committee Meeting