SONAT EXPLORATION COMPANY
VESSEL FAILURE
Timothy Fehl
Jeremy Pearson
Jacob Vogt
BASIC OVERVIEW
• March 4, 1998, near Pitkin, Louisiana
• Separation vessel failure, resultant fire
• 4 workers killed, substantial damage to facility
THE COMPANY
• Sonat Exploration Company, a division of Sonat, Inc.,
exploration and energy production
• Oil and natural gas wells, site performed separation
and storage
• Personnel on-site included Sonat employees as well as
outside contract operators
THE PROCESS
• Fluid from nearby wells was directed to a separation
system.
• Facility was set-up to process fluid from two wells,
Temple 22-1 and Temple 24-1.
• The Test Train processed fluid from Temple 22-1, 270 ft
away.
• The Bulk Train was to process fluid from Temple 24-1,
10 miles away
THE PROCESS
• Each train had three separators to maximize recovery
of natural gas.
• The first two separators separated three components
(gas/oil/brine)
• Third separator separated two components (gas/oil)
THE PROCESS
• Brine from first separator dumped in a well, natural gas
was sent to pipeline, remaining gas/oil/brine sent to
second separator
• Brine from second separator sent to tanks for disposal,
natural gas sent to compressor, remaining gas/oil sent
to third separator
• Natural gas from third separator sent to different
compressor and crude oil sent to storage tanks
THE PROCESS
• The first separator had a maximum allowable working
pressure of 1440 psig. Normally operated at ~900 psig.
• The second separator had a MAWP of 500 psig,
normally operating at ~225 psig
• The third separator had a MAWP of only 0 psig and
was designed to operate at atmospheric conditions. No
pressure relief valve.
TIMELINE
• 5:10pm – Valve 22 opened
• Construction supervise at valve 23
• 5:35pm – Increased well flow rate
• 6:00pm – Pressure extremely high
• 6:10pm – Final oxygen reading
• Left to check valve 300 ft. away
• Ready for start-up
TIMELINE CONTINUED
• 6:10pm – Workers near header
• 5:40pm – More workers group up
• 6:13pm – 4 operators move closer
• Employee checks tanks
• Contract operator stays at header
• 6:15pm – Catastrophic Failure
• Gas from Rupture ignites
• Additional fires
TIMELINE CONTINUED
• 6:20pm – Emergency shutdown
• Both wells shut down
• Shutdown gas sales pipeline valve
• 6:30pm – Pipeline still full
• 9:47pm – Fires extinguished
RESULTS
• 4 deaths
• $200,000 in damages
ROOT CAUSES
• Management didn’t use a formal engineering design
review process or require an effective hazard analysis
in designing and building the facility.
• Sonat engineering specifications didn’t ensure that
equipment that could possibly be exposed to high
pressure was protected by relief devices
• Management didn’t provide standard operating
procedures to employees.
CSB Chairman: the
honorable John Bresland
http://www.youtube.com/watch?v=xl2YuLdHZzg
LESSONS LEARNED
• Institute a formal engineering design review process
and include analysis of process hazards
• Implement a system to ensure all equipment that could
possibly be over-pressurized be fit with some sort of
relief system
• Develop written operating procedures for production
SUMMARY
• Overview
• Oil/Gas Separation Process
• Line that exploded was being started for the first time (purging)
• The Incident
• Over-pressurization of third separation vessel
• Resulting in 4 deaths and $200,000 in damages
• Causes and Lessons Learned
• Formal engineering review process/Analysis of process hazards
• Pressure relief systems
• Written operating procedures
REFERENCES
•
AcuSafe.com, CSB Releases Report at Sonat Exploration Company’s (now El Paso
Production
Company) Near Pitkin, LA, 2002. <http://www.acusafe.com/Newsletter/Stories/1000News-CSBPitkin.htm>,
February 2012.
•
William Bridges, Selection of Hazard Evaluation Techniques,Process Improvement Institute, USA, 2004.
•
Janet Etchells and Jill Wilday, Workbook for chemical reactor relief system sizing, Crown, 1998.
•
Bryn Harman, Oil And Gas Industry Primer, investopedia.com, May 21, 2007.
<http://www.investopedia.com/articles/07/oil_gas.asp#axzz1nyavYiAt>, February, 2012.
•
Gerald V. Poje, Isadore Rosenthal, and Andrea Kidd Taylor, Investigation Report Catastrophic Vessel
Overpressurization (4 Deaths).
•
U.S. Chemical Safety Board. Presentation of Findings. <http://www.csb.gov/assets/document/9_15_00 Slide-Presentation-on-Sonat-Investigation-Findings.pdf>
QUESTIONS