Williams is continuing its investigation into what caused a Jan. 18 rupture of a natural gas pipeline and resulting spill of liquid gas condensates into Parachute Creek, but says the incident didn't contaminate groundwater.
Shawn Whitmore, operations manager for the oil and gas pipeline and processing company's Piceance Basin assets, told the Garfield County Energy Advisory Board late last week that the company is completing excavation of the rupture site about six miles north of Parachute and has had an investigative team on site to determine how the pipeline broke.
He said Williams won't put the line back in service until it can be "absolutely confident" of the line's integrity.
The 16-inch diameter line ruptured in the middle of the night and was reported by a Caerus Oil and Gas employee. Within a half hour, Williams had acted to shut down the line. By then the line had leaked an estimated 13 barrels (546 gallons) of hydrocarbons and another 13 barrels of water produced in gas development. Whitmore estimated that Williams has recovered about 12 barrels of the hydrocarbons and 12 barrels of produced water.
He said snowmelt runoff as the temperatures rose that day carried condensates into the creek, and the first day testing showed benzene levels of 9.4, 9 and 8.5 parts per billion in the creek, with the levels being lower at each test site downstream. Subsequent testing for benzene and other condensate constituents have shown nothing above Colorado Oil and Gas Conservation Commission limits, which include 5 ppb for benzene, he said.
The gathering line transports gas from wells to Williams' gas processing plant in the Parachute Creek area. The line went into service in the 1990s, Whitmore said.
Some wells were shut in due to the line being out of service.
A Williams leak discovered in 2013 from a gas liquids line leaving its plant involved an estimated 50,000 gallons, with most of it vaporizing but an estimated 10,000 gallons leaking into the ground. Some benzene, which can cause cancer, reached Parachute Creek and significant amounts of benzene reached groundwater in that case. Whitmore said the current situation is "not in any way similar" to that one, but Williams recognizes the community concerns surrounding it and the matter is important to the company.
"One thing that will not change from 2013 is Williams' commitment to making sure our response to this incident … is thorough and complete," he said.
Williams has removed about 1,700 cubic yards of contaminated soil.
Whitmore said Williams has pressure transmitters on its lines that potentially can indicate ruptures, but there was a power outage the night of the incident. He said the company is investigating the possibility of having a backup power supply for such transmitters.
On Jan. 14, Caerus experience a leak of an estimated 113,000 gallons of produced water from a line west of Parachute. The fluid included benzene and other contaminants, and some of it reached surface water in a gravel pit. Caerus says the leak didn't reach the adjacent Colorado River.
Caerus says the leak from the 10-inch diameter line occurred when water in a 3/8-inch diameter stainless steel tubing leading to a pressure transducer froze. It has removed the tubing and transducer. Caerus official Jake Janicek told the county energy board that the company is looking at other Caerus lines that are similar as part of its effort to keep such a leak from happening again.