Texas Brine has provided initial reports this week from the Office of Conservation directive issued on Dec. 7, 2012, and further revised on Jan. 14, 2013, to use vertical seismic profile imaging to help define the edge of salt near Texas Brine’s Oxy Geismar #1 and Oxy Geismar #3 caverns in conjunction with 3-D seismic imaging of the area also required by the Jan. 14 directive. Results from the 3-D seismic, required by order to be submitted by April 21, 2013, will be used to verify the accuracy of the initial vertical seismic profile results. The preliminary vertical seismic profile results Texas Brine has provided to Assumption Parish officials and the Office of Conservation indicate that the Oxy Geismar #1 cavern sidewall, which begins at a depth of approximately 2,492 feet with a base at 3,228 feet, may be within 200 feet of the salt boundary, closer than indicated by previous top-of-salt maps used to define the subsurface, though the 3-D seismic data is needed to make confirmation of that boundary distance.
The recently completed vertical seismic profile image of the Oxy Geismar #3 cavern, making use of 2007 3-D seismic data that is available only around Oxy Geismar #3 and the 2010 vertical seismic profile done for that cavern, appears to be in close agreement with the previous imaging done for that cavern and edge of salt boundary. The Office of Conservation-ordered 3-D seismic imaging work is currently underway to provide more detailed information regarding the relationship of the salt edges to cavern sidewalls in the area. The Oxy Geismar #1 cavern has been inactive since November 2011 and had a micro-seismic monitoring array installed in February 2013 in accordance with Conservation directives. Conservation has also required ongoing pressure monitoring in 10-second intervals, as well as seismic monitoring in the Oxy Geismar #1 wellbore and surrounding area to monitor the stability of this area through previous emergency orders issued to Texas Brine. To date, that monitoring shows no indication of instability in the structure of Oxy Geismar #1. The State’s technical experts recommend maintaining a constant cavern pressure in Oxy Geismar #1 and continuation of existing monitoring. The State’s experts do not recommend any further action at this time. Upon completion of the 3-D seismic and ongoing analysis by the State’s technical experts and Assumption Parish Officials, a determination will be made regarding any additional actions that are necessary to protect public safety.