A group of U.S. drilling states, seismologists, academics and industry experts issued guidance Monday in a frank new report on handling human-induced earthquakes caused by hydraulic fracturing or the disposal of fracking wastewater.
The 150-page report, produced by the StatesFirst initiative, represents perhaps the most candid discussion on the topic since tremors across the mid-continent -- including in Oklahoma, Texas, Colorado and Ohio -- began being linked to fracking and deep-injection wastewater disposal around 2009.
It includes descriptions of how states handled various seismic incidents around the country, including their public relations strategies, and matter-of-factly references links between fracking or deep-injection wastewater disposal and earthquakes. Previously, public admissions had been fuzzy in some cases.
The group stopped short of suggesting model regulations, however.
That's because each state's laws and geography are unique, Ohio Oil & Gas Chief Rick Simmers, who co-chaired the effort, told The Associated Press. The report says "a one-size-fits-all approach would not be an effective tool for state regulators."
Simmers said the report is in the form of a primer, providing states with up-to-date scientific and technical data, case studies and several suggested approaches for detecting and managing the quakes.
Fracking involves blasting water and chemicals into shale formations to fracture the rock and release oil, natural gas and natural gas liquids trapped inside. The process involves thousands of gallons of water that becomes contaminated and must be trucked offsite and deposited at special deep-injection facilities.
Both processes have been associated with human-induced tremors, including some easily felt by people.
Simmers said the report conveys a plethora of important information, directing states on such issues as siting, well depth, construction methods, faults present at the site and how to judge an area's seismic history.
"Those two oil-and-gas activities do create some seismicity. It is very rare. If you compare it to the amount of fluid that's injected for disposal or the amount of fluid and the number of jobs that occur for hydraulic fracturing, it's very rare. But it does occur," Simmers said. "It is safe. We monitor the operations very carefully as do our counterparts in other states."
The working group arose after Ohio's discovery in April 2014 of a probable link between fracking and five small tremors in eastern Ohio near Youngstown. It was the first time in the Northeast that the new oil-and-gas drilling technique that had been sweeping the country had been linked to seismic activity, the second time in the U.S. and only the fourth time worldwide.
Earlier, Ohio Gov. John Kasich had halted disposal of fracking wastewater surrounding a well site in the same region after a series of earthquakes later tied to a deep-injection well caused a public outcry.
The StatesFirst coalition partnered with the Interstate Oil and Gas Compact Commission and the Ground Water Protection Council in the effort, which began last year.
The group gathered the most current science on the issue as a service to the 13 participating states: Alaska, Arkansas, California, Colorado, Illinois, Indiana, Kansas, Ohio, Oklahoma, Texas, Utah, West Virginia and Wyoming. Many have not experienced any earthquakes induced by fracking or wastewater disposal, but the report urges them to put regulations and procedures in place for dealing with any eventual incidents, including strategies for relaying the informatio to the public.
"Induced seismicity is a complex issue where the base of knowledge is changing rapidly," said Kansas Geological Survey interim director Rex Buchanan, a working group co-chair. "State regulatory agencies that deal with potential injection-induced seismicity should be prepared to use tools, knowledge, and expertise -- many of which are offered in this primer -- to prepare for and respond to (any) occurrences."
The report focuses primarily on deep injection wells for drilling wastewater, known as Class II wells. The vast majority of such wells have never been tied to earthquakes, but it is more likely that a tremor would come from one of those wells than from a hydraulically fractured well.
Wastewater containing chemicals, brine, naturally occurring radiation and mud is injected directly into basement rocks or into overlying formations that contain crevices into the basement rock. When this occurs near a sensitive fault, tremors can occur.