1. Sonat Exploration Company Vessel Failure
Timothy Fehl
Jeremy Pearson
Jacob Vogt

2. Basic Overview March 4, 1998, near Pitkin, Louisiana
Separation vessel failure, resultant fire
4 workers killed, substantial damage to facility

3. 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

4. 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

5. 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)

6. 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

7. 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.

9. 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

10. 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

13. Timeline Continued 6:20pm – Emergency shutdown Both wells shut down
Shutdown gas sales pipeline valve
6:30pm – Pipeline still full
9:47pm – Fires extinguished

14. RESULTS
4 deaths
$200,000 in damages

15. 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.

17. CSB Chairman: the honorable John Bresland

18. 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

19. 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

20. References
AcuSafe.com, CSB Releases Report at Sonat Exploration Company’s (now El Paso Production Company) Near Pitkin, LA, < 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, < 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. < Slide-Presentation-on-Sonat-Investigation-Findings.pdf>

21. Questions