On Tuesday, the Oklahoma Corporation Commission announced that it has issued a directive for further reductions in oil and gas wastewater disposal well volumes in Garfield County due to recent earthquakes. For now, the new directive applies to 23 active disposal wells.
Under the directive, all average daily volumes of Arbuckle disposal wells within 10 miles of the recent earthquake activity in the Covington/Douglas area will be reduced by another 20 percent. The total daily average reduction is about 11,226 barrels a day, which is in addition to past directives.
Scientists broadly concur that the disposal of saltwater from oil and gas operations into the Arbuckle — the deepest geological formation in the state — is the greatest risk for inducing earthquakes. The Arbuckle is hydraulically linked to the state’s granite basement, which has innumerable faults that are critically stressed and optimally aligned to slip.
The seismicity also was near Perry — about 17 miles away. The region experienced magnitude 4.6 and 4.5 quakes, respectively, in a 48-hour period in April, as recorded by the U.S. Geological Survey. The Oklahoma Geological Survey later downgraded the latter one to 4.0.
There were 19 quakes of at least 2.5 or greater magnitude from April 6-9, according to OGS data. That cluster of earthquakes helped push the state to 62 temblors this year alone of magnitude 3.0 or more — and 2,724 of that magnitude or more since 2010.
Wastewater injection in the earthquake-prone areas of Oklahoma was at about 37 million barrels in January, or about 1.1 million barrels per day, according to a Tulsa World analysis of government data. Peak monthly disposal was 95.4 million in October 2014, about 3 million barrels a day.
Also, well operators will be required to verify how deep the well is to make sure it isn’t too close to the basement rock. There is a lag between the time that the water is injected and when a fault slips and creates an earthquake. The lag varies and is not well understood, but it’s often on the order of about six months to a year. That can make it difficult to correlate quakes to a specific well or activity.
Compiled and Published by GIB KNIGHT
Gib Knight is a private oil and gas investor and consultant, providing clients advanced analytics and building innovative visual business intelligence solutions to visualize the results, across a broad spectrum of regulatory filings and production data in Oklahoma and Texas. He is the founder of OklahomaMinerals.com, an online resource designed for mineral owners in Oklahoma.