BAYOU CORNE — Speaking to concerned and frustrated residents in a boat launch parking lot Thursday, state and parish officials said they planned to start additional air monitoring on Friday and begin inspecting abandoned wells to hone in on the source of leaking natural gas in the area.
Authorities have been investigating whether pipelines, the 51 underground salt dome caverns carved from the vast Napoleonville Dome or other oil and gas infrastructure could be the source of natural gas escaping into the atmosphere.
The gas is causing water to roil with bubbles in about a dozen spots on Bayou Corne and Grand Bayou, officials have said.
Although short of any definitive answer, officials promised on Thursday to try to determine the cause.
“I will commit to you that we will stay with this,” Louisiana Conservation Commissioner Jim Welsh told John Achee Jr., 35, of Bayou Corne, who was among the people who responded to a public invitation issued Wednesday to attend Thursday’s community meeting at the boat launch.
Achee had asked Welsh to promise that his state Department of Natural Resources would stay on top of the issue. Achee had complained the response has been slow. The first report of bubbles surfaced on May 30.
Twice-daily tests continue to show the gas releases do not pose an ignition risk, parish officials have said.
DNR officials asked for patience and warned the process of pinpointing the source could take a while.
Joseph “Joe” Ball Jr., director of DNR’s Injection and Mining Division, said a prior gas leak that sparked a two-month evacuation of residents in the vicinity starting in late 2003 was from a source authorities knew about, a salt dome cavern that leaked the gas.
“This is totally different. There is no known source right now, so it’s going to be a process of elimination of looking at possible sources, and that’s what we’re working on right now,” Ball told several dozen residents, news reporters and public officials encircling him at Sportsman’s Landing boat launch along Bayou Corne and La. 70 South.
Ball noted the underground salt dome caverns inspected so far have tested “tight” and do not appear to have problems.
Fifty-one underground caverns exist in the 3-by-1-mile Napoleonville Dome, said John Boudreaux, director of the Assumption Parish Office of Homeland Security and Emergency Preparedness.
Shaped like vertical, 2-liter soft drink bottles, the caverns are created from the extraction of brine from the salt dome 700 feet below ground level. Nineteen caverns store hydrocarbons and two of those 19 hold natural gas, Boudreaux said.
During the meeting and in interviews, some residents asserted that bubbling water has been seen in the Bayou Corne area for 15 to 25 years but the issue has only recently worsened and gotten attention from public officials.
Brent Campbell, DNR Pipeline Division director, detailed extensive checks of three pipelines under the bayous. The pipelines owned by either Crosstex Energy LP of Dallas, Texas, or Acadian Gas Pipeline of Houston, Texas, have not given indications of leaks.
Also emerging from the steamy meeting Thursday were reports of earth tremors that rattled homes and cracked residential concrete slabs.
“I want to know what’s shaking my house. That’s what I want to know,” Debra Charlet, 54, of Bayou Corne, told gathered officials at one point.
Ball did not dispute reports of a June 8 tremor but said U.S. Geological Survey seismic monitors did not detect the tremors.
“We know it happened because you guys reported it. It’s just that their instruments weren’t sensitive enough to detect it,” Ball said.
He said officials do not know the cause, however, whether the tremors are connected to natural gas leaks — which have expanded in number since the May 30 report — or are from natural subsidence common in the area.
Ball noted Louisiana’s earthquake of greatest magnitude occurred in the area in 1930.
In a later interview, Charlet, who said she is from California, said the June 8 tremor felt similar to the larger quakes in her former home state.
Welsh told residents his office would be working with Louisiana Department of Environmental Quality officials on Friday to inspect abandoned oil and gas wells as a possible gas source.
Welsh said his department’s engineers have reviewed well records for about 50 wells and found 17 older wells where DNR records are not enough to reliably check them.
DEQ officials will train a special infrared camera on the wells to detect leaking hydrocarbons invisible to the eye, said Karen Price, DEQ senior environmental scientist.
Boudreaux said air monitors would be deployed Friday behind a Bayou Corne neighborhood to continuously check for ignition risks.
He and DNR officials also said more sensitive testing of air collected from leak sites will try to determine the origin of the gas. Results are not expected back for about 20 days.