Earthquakes have become more than 10 times more common in normally quiescent parts of the U.S., such as Ohio and Oklahoma, in the past few years. Given the simultaneous uptick in fracking—an
oil and gas drilling technique that involves fracturing shale rock deep
underground with the use of a high pressure water cocktail—it’s common
to suspect a link. There might be one,
but the real culprit behind the largest earthquake in Oklahoma’s
recorded history is not what goes down but what comes up with the oil:
Oklahoma has long benefited from a robust oil industry. One of the
side effects of oil production is that a lot of water flows back to the
surface with the petroleum. That flowback water must be disposed of,
because it is laced with all kinds of contaminants the liquid solvent
has picked up during its long residence deep underground, ranging from
trace amounts of radioactive elements to lots of salt.
In Oklahoma and in much of the rest of the country, the most common burial ground for such wastewater—whether
we’re talking oil or gas—is a disposal well back underground. Oil
producers in central Oklahoma had been using this approach for 18 years
when a swarm of powerful earthquakes rumbled across the countryside
starting on November 5, 2011. The biggest temblor, a magnitude 5.7 felt
as far away as Milwaukee, was linked to pumping yet more wastewater down
old oil wells in the vicinity. (The wastewater pumping there continues despite the quakes.)
According to a new study published online March 26 in Geology,
the earthquake was indeed caused by filling up the old oil cavities
with water until there was simply too much pressure on the surrounding
rock. Records showed that after years of requiring little pressure to
dump the wastewater, oil operators recently have had to actively pump
the water down the old wells to overcome a more than 10-fold increase in
underground pressure, which peaked at 3.6 megapascals, or 525
pounds-per-square-inch. That’s because the volume of wastewater pumped
down had exceeded the volume of oil extracted, suggests the team of
researchers from the University of Oklahoma, Columbia University and the
U.S. Geological Survey. That increased pressure then caused the rock to
jump along a pre-existing fault, known as the Wilzetta Fault.
Which makes me wonder about the advisability of allowing a new disposal well field for fracking fluids in this active earthquake zone, and near a college, no less.
From the Ojai Valley News, dated March 7. 2013:
By Kimberly Rivers
"A new oilfield waste disposal facility, including an underground injection well for storing oilfield fluids (and potentially fracking fluids) could become a reality in Ojai’s backyard in the very near future.
Pending before county planners is a proposal from Anterra Waste for a new Class II oilfield waste disposal facility, near the Santa Clara River in Santa Paula. “Class II fluids are waste streams associated with oil and natural gas production operations,” according to the notice on the county’s website.
Related to that proposal, Anterra is pursuing a lease for county land — about a half mile from proposed facility — to drill and operate a Class II injection well that would inject waste from oil and natural gas production deep into the earth for disposal and storage.
Mirada Petroleum also has applied to the county of Ventura to expand an existing conditional use permit for oil leases in Upper Ojai behind St. Thomas Aquinas College, paving the way for eight new oil wells."
Okay. Now. If the injection of fracking fluids into a disposal field set off an earthquake, that damaged the college or its cathedral, wouldn't regulators be potentially liable for approving it, knowing the risks?