State had 400 oil, gas spills in 2012, report says
About 400 oil and gas spills were reported to the Colorado Oil and Gas Conservation Commission last year, including 66 instances in which ground or surface water remediation measures were required.
That’s according to a report recently prepared by Jim Milne, the agency’s environmental manager, who reviewed the findings with the commission at its last meeting.
The report showed 399 spills were documented last year, including 375 reported by the industry, 17 resulting from commission inspections and six resulting from landowner complaints.
Sixty-three had groundwater impacts, and 22 impacted surface water, although Milne clarified that the latter figure includes spills into dry as well as wet drainages. No water wells were affected.
Ninety-four cases required contaminated soil to be excavated, with 32 more cases requiring further soil remediation work. In 142 cases, the spilled fluids were recovered and no soil impacts occurred. Further research is needed to categorize several dozen spills.
The 2012 total is the fourth-highest in the last decade. The highest was 527, reported in 2011. During the state’s drilling peak of 2008, 430 spills were reported. However, Colorado’s active well count now exceeds 50,000, compared to about 34,000 at the start of 2008.
More than half of last year’s spills—211—resulted from equipment failure. Sixty-five were the result of human error, and 62 were historical, a reference to old leaks discovered during current operations.
Twenty-one were the result of vandalism, which Milne said stemmed from the “unusual event” of vandals opening valves on numerous condensate tanks in Weld County last year.
Seventeen spills were caused by pit closures, three by pit leaks and two by lightning, with 18 resulting from other causes.
Milne said the data suggests that “perhaps some of these are preventable,” as in human-caused incidents, and Oil and Gas Conservation Commission staff will look at whether it can convey things it has learned to companies to help prevent spills.
Of the spills, 110 involved oil/condensate, 123 produced water, and 75 a combination of those categories. Thirty-nine spills involved drilling mud, four cases involved flowback fluids from wells, and the fluids in 30 cases are unknown.
The spill amounts for oil/condensate ranged from less than a gallon to 398 barrels (a barrel contains 42 gallons). The produced-water spills ranged from one to 900 barrels, with the largest involving a pit leak in Las Animas County.
The report doesn’t break down spills by regions or counties. But the commission website shows that last year 30 spills were reported in Garfield County, 24 in Rio Blanco County, six in Mesa County and four in Gunnison County.
The region’s largest in aerial extent covered about 23,000 square feet at a Rio Blanco County site owned by XTO Energy, a subsidiary of ExxonMobil Corp., and involved a historical release and a compromised pit liner.
Milne said one thing the commission is finding, however, is that the aerial extent of a spill often doesn’t correspond with the seriousness of impacts. A spill on a well pad or compact surface can spread far laterally but not infiltrate into the subsurface, where responding to it can be more difficult.
“If they can see it on the surface it’s a lot easier to deal with quickly,” he said.
The Williams natural gas liquids spill near Parachute Creek did not spread far on the surface but traveled hundreds of feet in groundwater. That spill, which is believed to have begun in December but wasn’t discovered until this year, ultimately was determined to be outside the commission’s jurisdiction.