Thu March 13, 2014
Regulator Votes to Adopt New Rules for Disposal Wells in Earthquake-Prone Region
The Oklahoma Corporation Commission on Thursday voted unanimously to adopt new data monitoring and reporting rules for operators of disposal wells in central Oklahoma’s earthquake-prone Arbuckle Formation.
These are the first formal state regulations that address oil and gas-related earthquakes. The rules require operators in the Arkbuckle to record daily injection pressure and volume measurements, and turn the data over to the commission if requested.
Previously, operators were only required to record monthly measurements. State, federal and university scientists say limited data from disposal well operators has hampered their efforts to study how the wells, which are used by the oil and gas industry, could be linked to Oklahoma’s so-called earthquake “swarm.”
Several peer-reviewed studies have concluded that waste fluid injection into disposal wells is likely responsible for increased earthquake activity in Oklahoma, including the November 2011 quake that struck near Prague. The most recent study, which was published March 10 in the Journal of Geophysical Research and suggested the November 2011 quake — Oklahoma’s largest — was triggered by a cascade of smaller quakes triggered by a nearby disposal well.
The study’s principal author, Danielle Sumy, says more real-time data will help researchers build better seismic models and study how fluid injection causes faults to slip.
“It’s a matter that we really need to look into more carefully,” she says. Ultimately, Sumy says state officials need to “understand the level of pressure that’s it’s OK to inject at before it needs to be shut off.”
Disposal wells are suspected of triggering earthquakes in at least a half-dozen other states, but while Oklahoma’s November 2011 quake is likely the largest ever linked to oil and gas-related waste water injection, the state’s regulatory response has been more passive than other states’, StateImpact reported in May 2013.
The Corporation Commission in September 2013 ordered a disposal well operator to reduce injection pressure and volume after a series of quakes rumbled near Marietta in south-central Oklahoma’s Love County. Recently, the agency has denied permits for disposal wells over earthquake concerns, Commissioner Dana Murphy says.
The new disposal well monitoring rules have to be approved by the Oklahoma Legislature and Gov. Mary Fallin before they’re formalized.