A dramatic increase in earthquakes in central Oklahoma since 2009 is likely attributable to subsurface wastewater injection at just a handful of gas wells, according to a study published in the journal Science.
The research team was led by Katie Keranen, professor of geophysics at Cornell University, who says Oklahoma earthquakes constitute nearly half of all central and eastern US seismicity from 2008 to 2013.
“Induced seismicity is one of the primary challenges for expanded shale gas and unconventional hydrocarbon development,” she says
“Our results provide insight into the process by which the earthquakes are induced and suggest that adherence to standard best practices may substantially reduce the risk of inducing seismicity.
“The best practices include avoiding wastewater disposal near major faults and the use of appropriate monitoring and mitigation strategies.”
The study found four of the highest-volume disposal wells in Oklahoma are capable of triggering 20% of recent central US earthquakes in a swarm covering nearly 2,000 square kilometres.
Development of new sources of shale gas and oil, via horizontal drilling and hydraulic fracturing, has grown rapidly in recently years and has offset declines in production from conventional reservoirs in America.
The US is now building shipping terminals to export gas.