Vent wells burning gas from Assumption sinkhole
BATON ROUGE, La. (AP) — Officials say they've begun burning methane trapped in a water aquifer around a giant sinkhole in Assumption Parish.
Burning the gas could help stabilize the salt dome, which released natural gas and crude oil as it collapsed near Bayou Corne.
Three vent wells already are burning off gas, The Advocate reports. Texas Brine Co. plans to start flaring Monday at a fourth existing well converted to gas removal, company and parish officials say.
Texas Brine got the first well to start burning gas Nov. 2.
Shaw Environmental and Infrastructure, hired by the state, has since started burning gas at two wells, including one Thursday, parish officials say.
The sinkhole, now 8 acres at the surface, is in a swampy area leased by Texas Brine from Occidental Chemical Corp. The gas was released into the aquifer after a Texas Brine salt cavern failed in August, and since then, the gas has permeated even-shallower sediments.
John Boudreaux, director of the parish Office of Homeland Security and Emergency Preparedness, said the more wells in place, the more gas that can be removed from underground.
"And, hopefully, the sooner they can get it stabilized," he said.
The Office of Conservation has ordered Texas Brine to take over the vent well operations and add more wells. Boudreaux said two new vent well sites have also been proposed, though routes to the sites are still being developed.
Boudreaux said estimates show the three vent wells had released 558,000 cubic feet of gas through Friday morning. A fourth well that the state ordered Texas Brine to drill months ago has burned another 598,000 cubic feet of gas through early Friday.
A gas release in late 2003 near the Grand Bayou community from a storage cavern prompted installation of 36 vent wells. They removed 375 million cubic feet of gas before they were shut down in 2004. State officials have said the 2003 incident is not comparable to the sinkhole because the 2003 gas was at much higher pressures.
Officials said that the gas freed by the cavern collapse now poses a risk to Bayou Corne residents who have been evacuated from their homes for more than three months. Meanwhile, officials have called for in-home air monitoring and detectors and ventilation systems for slab-foundation homes.
Sonny Cranch, spokesman for Houston-based Texas Brine, said virtually all evacuated residents who picked up housing assistance checks Thursday from the company filled out forms allowing the equipment to be installed.