BATON ROUGE, LA (AP/WAFB) - The meeting included Assumption Parish President Marty Triche, Assumption Parish Police Juror Henry Dupre, Assumption Parish Emergency Operations Center Director John Boudreaux, State Senator Rick Ward, State Representative Karen St. Germain, Assumption Parish Sheriff's Office Captain of Special Operations Bruce Prejean and officials from the Department of Natural Resources, Governor's Office of Homeland Security, Department of Environmental Quality, Department of Health and Hospitals, Department of Transportation and Development and State Police.
During the meeting, the governor's staff says Jindal outlined a contingency plan for Oxy-Geismar No. 1 cavern – another cavern owned by Texas Brine – after preliminary results indicated that the cavern sidewall may be less than 200 feet from the edge of the Napoleonville salt dome, closer than indicated by previous top-of-salt maps used to define the subsurface. The proximity of the cavern to the salt dome increases the risk of structural instability of the cavern walls, the governor's office says.
Scientists say the sinkhole formed after the collapse of an underground salt cavern operated by Houston-based Texas Brine Co. LLC, which extracted brine and piped it to nearby petrochemical facilities.
The Associated Press contributed heavily to this report.
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THE GOVERNOR'S OFFICE RELEASED THIS INFORMATION MONDAY AFTERNOON REGARDING THE CONTINGENCY PLAN FOR OXY-GEISMAR NO. 1 CAVERN:
Contingency Plan for Oxy-Geismar No. 1 Cavern
Preliminary Vertical Seismic Profiles (VSP) results indicate that the Oxy-Geismar No. 1 cavern sidewall is closer to the salt dome than indicated by previous top-of-salt maps used to define the subsurface. This means the cavern has an increased risk of collapse. 3-D seismic data is needed to confirm the exact boundary distance.
The Oxy Geismar No. 1 well is inactive and has a micro-seismic array installed into it. Along with the micro-seismic array network consisting of seven surface stations and two borehole stations, the stability of the western edge of the Napoleonville Dome, including Oxy-Geismar No. 1 is being monitored for any seismic activity. The micro-seismic array measures seismic activity on 10-second intervals.
Rock-mechanics modeling is currently being performed by Office of Conservation's contract experts to determine if a risk of collapse exists, and if so, how that would impact the surrounding area. Based upon observations associated with the collapse of the Oxy-Geismar No. 3 sidewall, a minimum of two to three months of prior warning would be expected before any surface instability would develop.
The major factors that could impact public safety if the Oxy-Geismar No. 1 cavern were to collapse are the development of a new sinkhole and the release of hydrogen sulfide (H2S) from the cap rock.
Oxy-Geismar No. 1 is also closer to La. 70 than Oxy-Geismar No. 3. The Department of Transportation and Development, in collaboration with DNR and GOHSEP, has developed a three part transportation plan in case the road is compromised: planned detours, a monitoring and warning system similar to rail road crossings, and potentially rerouting and rebuilding La. 70 farther north.
The proposed contingency plan is based upon three color levels (green, yellow, and red) of potential seismic activity associated with the Oxy-Geismar No. 1 and the related action level as described below. The response is currently in green status.
Seismic Activity: no confirmed micro-seismic events associated with Oxy-Geismar No. 1 Cavern stability detected. This is the current status. Action steps include:
1. Implement monitoring system for La. 70 and prepare a La. 70 closure plan for implementation.
2. Ongoing rock-mechanics modeling of stability of western edge of Napoleonville Salt Dome and updated to provide predictive model of short and long-term stability of the western edge of the Napoleonville Salt Dome, including the Oxy-Geismar No. 1 Cavern. Forthcoming 3D Seismic data and deep geologic core will be utilized in this process.
3. Evaluate potential response actions to shore up structural integrity of Oxy-Geismar No. 1, if necessary.
4. Direct Texas Brine Company to maintain wellhead pressure in Oxy-Geismar No. 1 at a level to be approved by state experts based on current conditions and operational considerations.
5. Permitting and design work on providing alternative access in case of La. 70 closure, conducted by DOTD and its contractors.
Seismic Activity: Initial confirmed micro-seismic events associated with Oxy 1 Cavern stability detected. Action steps include:
1. Immediately notify Assumption Parish Officials, GOHSEP, and State Police upon confirmation that micro-seismic activity has been detected. This information means that Oxy-Geismar No. 1 shows signs of potential structural instability and that surface instability associated with Oxy-Geismar No. 1 is possible within two to three months, or as otherwise determined by rock mechanics modeling.
2. Initiate response actions determined necessary to shore up structural integrity of Oxy-Geismar No. 1 if feasible.
3. Operators of nearby hydrocarbon storage caverns are ordered to undertake all necessary steps to secure their caverns and flow lines, implement H2S (hydrogen sulfide) monitoring protocols, and prepare for evacuation of their sites as soon as possible. Continuous high-frequency reporting to DNR-OC of well/cavern pressures to begin for these caverns.
4. All Napoleonville Salt Dome operators are notified of the situation and to implement H2S protocols.
5. All other operators of infrastructure in the area are ordered to take necessary precautions.
Seismic Activity: Several hundred micro-seismic events associated with Oxy 1 Cavern stability detected during any 12-hour time period. Action steps include:
1. Immediately notify Assumption Parish Officials, GOHSEP, and State Police that activity has been detected demonstrating that Oxy 1 Cavern shows signs of ongoing structural instability and that surface impact associated with Oxy 1 Cavern may be imminent. Evacuation will be recommended to local officials.
2. Shut in all natural gas vent wells in the Bayou Corne area due to the potential for H2S release from cap rock in the event of a roof collapse of the Oxy 1 Cavern. Natural gas vent wells will remain shut-in until appropriate H2S safety measures are implemented.