Companies have gone through the process of formally abandoning nearly 400 oil and gas flowlines in western Colorado’s Piceance Basin as a result of a state-ordered review after a fatal explosion in Firestone earlier this year.
Stuart Ellsworth, engineering manager for the Colorado Oil and Gas Conservation Commission, provided an update on the results of the review Thursday at the quarterly Northwest Colorado Oil and Gas Forum in Rifle.
The review was ordered after an April home explosion in Firestone killed two people and seriously injured a third. It was caused by gas from a nearby well’s old flowline that somehow remained connected to the well and wasn’t capped, and was cut off near the home during the neighborhood’s construction.
Flowlines connect wells with equipment such as separators and tanks. The oil and gas commission ordered that by the end of May, companies provide the state with an inventory of flowlines within 1,000 feet of buildings, and mark and cap all flowlines not in use, regardless of their distance from buildings.
By the end of June they had to pressure-test all lines within 1,000 feet of buildings and properly abandon all lines that they own that are not in use, or test them and put them back in use.
Statewide, 177 companies have responded to the state’s order. Ellsworth said about 14 companies haven’t responded.
“They tend to be one- or two-well operators,” he said, and state officials are reaching out to ask them to respond to the order.
Statewide, the commission has received flowline information associated with more than 23,000 wells. More than 30,000 tests were conducted, and companies have abandoned some 7,600 lines.
Ellsworth said 462 lines failed their tests. Five percent were repaired or replaced, and most of the rest were locked and tagged pending repair or replacement or abandonment, or have been scheduled for abandonment.
Companies haven’t yet told the state of their plans for the other 6 percent, and finding that out is a priority for the state, Ellsworth said.
In the Piceance Basin, the commission received information related to 4,680 oil and gas facilities within 1,000 feet of homes, and 8,627 flowline segments. More than 7,000 passed pressure tests, 10 failed, and companies have decided to abandon 395 lines.
Abandoning lines involves disconnecting them from equipment, purging them, cutting them off underground at each end and capping them. Alternatively, lines can be removed.
The Piceance Basin oil and gas facilities identified in the review included 2,873 in Garfield County, 926 in Mesa County, 737 in Rio Blanco County, and 114 in Routt County.
In Garfield County, 6,114 lines passed tests, three failed, and 222 lines were abandoned. In Rio Blanco County 239 lines passed tests, two failed and seven were abandoned. In Mesa County 46 lines passed, two failed and 87 lines were abandoned.
Three lines failed in Gunnison County, 655 passed and none were abandoned.
In Delta County, where no facilities close to homes were reported, no lines were tested but 46 were reported and all were abandoned.
In Routt County, two lines passed and neither failed, but 33 were abandoned.
While data analysis and other flowline review work is ongoing, Ellsworth views the undertaking as a success.
“It was appreciated that the operators jumped on this and engaged as fully as they could within the time frame,” he said.