Gas in Assumption Aquifer Thought to Be from Sinkhole

A state seismic expert has found two likely existing “deep” sources continuing to feed methane gas under the Bayou Corne and Grand Bayou communities in the area of northern Assumption Parish in Louisiana.

But officials working on the removal of the gas, a suspected byproduct of the formation of the Bayou Corne-area sinkhole last year, said they are focused on cutting off or removing gas in two shallower layers first while they work on how to eliminate these two deeper sources.

During the parish community meeting where the new seismic results were revealed, The Advocate reports some residents complained that response officials had not gone after the deep sources first.

Bayou Corne businessman Dennis Landry asked whether drilling to remove the gas from the deep sources was still a viable option as had been discussed at a previous meeting.

Gary Hecox, CB&I hydrogeologist and leading scientist on the sinkhole response, said drilling for the sources is certainly viable.

“The problem you’ve got, is even if we start drilling tomorrow and relieve that gas, there is so much gas in the aquifer you probably would not even notice it,” he said during the presentation to 40 to 50 residents.

Hecox added it may take years for an effect to be seen. He has said the gas in the aquifer is much greater than the 45 million cubic feet once estimated and is collected heavily under the Sportsmans Drive community south of La. 70 in Bayou Corne.

Rising gas unleashed by the failure of a Texas Brine Co. salt dome cavern last year has presented a continuing risk of explosion for the communities that once held about 350 people and remain under a more than year-old evacuation order. The cavern failure is also suspected of causing the 25-acre Bayou Corne-area sinkhole.