The plot has thickened around the mystery of natural gas bubbles that have been seen in two bayous in Assumption Parish, LA. Geologists and other experts are monitoring an area of swampland that has liquefied into muck. Segments of pipelines passing by the affected area have been depressurized and shut in.
During the depressurization operation, Louisiana Rte. 70 was closed for more than 24 hours. Four pipelines in the area have been shut and depressurized, according to officials.
According to Assumption Parish Police Jury spokeswoman Kim Torres, at least one of the pipelines, owned by Crosstex Energy LP of Dallas, has shifted.
Homes and businesses in the Bayou Corne and Grand Bayou areas were evacuated. The "slurry" area appeared overnight last Friday and quickly spread. On Saturday it expanded and bent a 36-inch diameter Crosstex natural gas pipeline about 18 feet, Torres said.
Crosstex confirmed to NGI that its 36-inch diameter pipeline had been shut in. Spokeswoman Jill McMillan said she could not say what volume of gas was affected.
"Crosstex Energy has responded to the slurry situation located near our pipeline," McMillan said. "Our well trained personnel have taken immediate action. Our highest priority is to ensure the safety of all involved. As a precautionary measure, Crosstex has isolated and shut down the pipeline. We have notified our customers and see no major disruptions in the area. We will continue to monitor our operations and work with local emergency officials. We will release additional information as it becomes available."
Other pipelines affected are owned by Acadian Gas Pipeline LLC, which is a unit of Enterprise Products Partners LP, and Florida Natural Gas.
Enterprise spokesman Rick Rainey said two 20-inch diameter Acadian natural gas pipelines in the same right-of-way have been shut in and a temporary pipe to bypass the affected area was put in place, so customers have not been affected. Acadian's Haynesville pipeline terminates in the area, but it has not been affected either, Rainey said.
He said the company did not know yet whether its pipes had shifted due to the disturbed area. When bubbles began appearing in the area, Enterprise checked its system for leaks and everything checked out, Rainey said. "It's kind of a mystery right now" what's causing the slurry hole, he said.
Speculation has been that the bubbling could be caused by a leakage from a salt dome underlying the area, but nothing has been confirmed.
Rodney Mallett, a spokesman for the Louisiana Department of Environmental Quality, said water samples were taken in the area and preliminary tests show that there is diesel in the water. "We're still trying to find the source of the diesel," he told NGI. The results from air sampling will be known in a day or two, he said Monday. It would not be surprising to find natural gas in the air samples, he said.
The Louisiana Department of Natural Resources (DNR) is the lead state agency investigating the matter. A DNR spokesman did not immediately respond to a request for comment.
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