State regulations in Oklahoma could drastically reduce the number of magnitude-3 or higher earthquakes linked to injection wells used to dispose of drilling waste from horizontal hydraulic fracturing, says a Stanford University study published in Science Advances. Researchers say the regulations—which call for a 40 percent reduction in the volume of saltwater being injected in the seismically active areas—should significantly decrease the number of man-made earthquakes "by the end of 2016 and approach historic levels within a few years."
Oklahoma had more earthquakes in 2015—903 of magnitude 3.0 or higher—than the combined total of every state except Alaska. Prior to the oil and gas boom that began in 2009, Oklahoma averaged two earthquakes of magnitude 3.0 or higher per year. The U.S. Geological Survey in March for the first time released maps of earthquakes attributable to human activity. USGS has attributed Oklahoma's increased seismic activity to injection wells. (Stanford map: Oklahoma earthquakes)
The study does have some problems, Mike Soraghan reports for Energywire. The model and prediction "assumes wastewater disposal doesn't increase in earthquake-prone areas. The current decline has been caused both by regulatory restrictions and reduced production because of low oil prices. The model predicts about 250 quakes of magnitude 3 or greater next year and about a 40 percent chance of a quake of magnitude 5 or greater."
Justin Rubinstein, a research geophysicist heavily involved in the Geological Survey's research into the man-made quakes, "said the Stanford model makes sense but seems optimistic," Soraghan writes. "Rubinstein noted some of the uncertainty in the study. The model is adapted from one used for much simpler scenarios—geothermal or oil and gas operations associated with a single well. And within their broad prediction," the study's authors "allow that isolated areas could continue having unusual quake levels beyond the predicted five to 10 years."
Oklahoma had more earthquakes in 2015—903 of magnitude 3.0 or higher—than the combined total of every state except Alaska. Prior to the oil and gas boom that began in 2009, Oklahoma averaged two earthquakes of magnitude 3.0 or higher per year. The U.S. Geological Survey in March for the first time released maps of earthquakes attributable to human activity. USGS has attributed Oklahoma's increased seismic activity to injection wells. (Stanford map: Oklahoma earthquakes)
Justin Rubinstein, a research geophysicist heavily involved in the Geological Survey's research into the man-made quakes, "said the Stanford model makes sense but seems optimistic," Soraghan writes. "Rubinstein noted some of the uncertainty in the study. The model is adapted from one used for much simpler scenarios—geothermal or oil and gas operations associated with a single well. And within their broad prediction," the study's authors "allow that isolated areas could continue having unusual quake levels beyond the predicted five to 10 years."
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