Collaboration paying off in state’s quake efforts

Afew years ago, there was a whole lot of shakin’ going on in Oklahoma as noticeable earthquakes occurred with regularity. The shaking has been subsiding, which is good news, although that’s tempered a bit by a report that sections of northern and central Oklahoma could see damaging man-made quakes in 2017.

It’s a prediction, not a certainty, by the U.S. Geological Survey, one that state regulators hope is avoided through continued monitoring and new regulations crafted in collaboration with the oil and gas industry.

Two weeks ago, the Oklahoma Corporation Commission issued new limits regarding wastewater disposal for 654 disposal wells across a large portion of the Arbuckle formation, which is the deepest sedimentary rock layer throughout much of the state. The commission in the past two years has implemented and revised numerous rules regarding Arbuckle disposal.

The Oklahoma Geological Survey notes that the rate of earthquakes in Oklahoma has fallen significantly since 2015. That year, the state each day averaged 5.39 magnitude-2.7 or greater quakes. In 2016, the average fell to 3.6 per day. Through the first two months of 2017, the average was 1.38 — and these drops have corresponded with increased drilling.

OGS Director Jeremy Boak says his scientists expect the rate to continue to decline but that “it would not be totally out of the question to see another moderately large earthquake.”

In a report last week, the U.S. Geological Survey said the overall seismic hazard this year from natural and induced quakes is lower than the forecast for 2016. However, “there is still a significant likelihood for damaging ground shaking” in the central and eastern United States.

In Oklahoma, the federal agency’s hazard map puts the highest chance of a damaging quake at 10 percent to 12 percent in an area near Pawnee. This is the same area that six months ago experienced the strongest recorded quake in state history, registering 5.8 in magnitude.

Referring to induced seismicity, a USGS official said millions of Americans face “a significant chance of experience damaging earthquakes, and this could increase or decrease with industry practices, which are difficult to anticipate.”

Here’s hoping they continue to decrease in Oklahoma, as the industry helps formulate and adheres to the evolving Corporation Commission regulations. These efforts have focused on how deep wastewater wells should go, and how much volume they should hold. Companies that don’t toe the line know their wells can be shut in, which has happened in some cases.

The head of the commission’s oil and gas conservation division notes that the goal moving forward is to try to ensure there isn’t “a sudden, surprise jump” in disposal volumes. Meantime, researchers from Stanford University have come up with a new tool to help regulators and the industry calculate the risk of wastewater injection wells triggering quakes.

There are no sure bets in this area, of course, but the continued collaboration and research can only help to keep to a minimum significant shaking related to activity in the Oklahoma oil patch.