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>

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