Lines leading from oil or gas wells were sources of many spills, say data from states that collect it

Top five causes for spills in Colorado,
New Mexico and Texas, the states
that report spill sources. Records for
New Mexico and Texas go back to
2009, Colorado data to April 2014.

Flow lines—the small, low-pressure pipes blamed for a fatal home explosion in Colorado last month—have been cited as the problem in more than 7,000 oil and natural gas "spills, leaks and other mishaps since the beginning of 2009, according to an E&E News analysis of state agencies' records," Mike Soraghan reports for Energywire. "And that is likely an undercount because of the widely varying ways in which states report spills."

"There are different terms for flow lines, but generally they refer to narrow pipelines that carry oil, gas or wastewater—often all three—from scattered wells to tanks or other equipment within the same lease," Soraghan writes. "Other lines, like gathering lines and transmission pipelines, are larger. They lead to processing facilities and away from production sites."

Flow lines (Colorado Oil and Gas
Conservation Commission photo)

Flow lines are "prone to corroding and leaks, lines freeze, and joints break" and they also can get cut and crushed by heavy equipment, Soraghan writes. "In most states, that hasn't led to stricter regulation. Only Colorado and California have specific rules for such small pipelines. Colorado requires the lines to be pressure tested but doesn't require detailed maps. California is still implementing its requirements for mapping and pressure tests."

"Flow lines are more common with conventional oil and gas development, in which vertical wells are scattered across vast acreage. In modern shale development, horizontal well bores spread out underground," Soraghan reports. "But wellheads are concentrated in one area at the surface, so there's less need for long flow lines. They usually leak oil or 'produced water'—a salty, toxic mix of fluids—along with natural gas. The gas leaked from such lines often isn't reported."

Kerry Sublette, a spill cleanup expert and chemical engineering professor at the University of Tulsa, told Soraghan, "In a lot of these mature fields, they haven't been replaced in a long time. If nobody's looking over your shoulder, you're not as likely to replace it." Soraghan notes that "most states don't require that operators dig up and remove the lines when they're done using them." Sublette told him, "They've got lines that they've got no idea where they go. They never remove them."