What do the Horn River Basin in Canada and Garvin County, Okla., have in common? As Carole King sang a few years ago, “I feel the earth move under my feet. I feel the sky tumbling down, tumbling down,” and that’s when the ground starts shaking.
This time, though, it’s not from injection wells; it is from hydraulic fracturing of individual wells. The last time I touched on this topic was in the January 2014 issue of E&P. Most of the focus was on earthquakes induced by wastewater injection wells. Since then the industry has been faced with a lot of pressure (the pun is intended) to stop using injection wells, which in turn would shut down horizontal wells and hydraulic fracturing.
Now there is some evidence that it’s not only injection wells that can cause earthquakes; it’s also single wells being hydraulically fractured. Peter Duncan, founder and co-chairman of MicroSeismic, talked about it during a presentation at the company’s booth at the Unconventional Resources Technology Conference in San Antonio July 20 to 22. He forwarded some presentations (August 2012 and December 2014) from the British Columbia Oil and Gas Commission to me.
The 2012 study looked at anomalous seismicity in the Horn River Basin from April 2009 to December 2011. More than 8,000 high-volume hydraulic fracturing completions were performed with no associated anomalous seismicity. However, 272 events were observed that “were caused by fluid injection during hydraulic fracturing in proximity to pre-existing faults.”
In the 2014 study the investigation found that from August 2013 to October 2014 there were 231 seismic events in the Montney area attributed to oil and gas operations. The report noted that 38 seismic events were induced by wastewater disposal and 193 by hydraulic fracturing operations. None of the recorded events caused any injuries, property damage or loss of wellbore containment. Events in the range from 2.5 to 4.4 magnitude on the Richter scale “may produce actual fault movements in the range of 1 mm to centimeters within the target formation at depth.”
In the 2012 study, the report described the Picket Unit B Well 4-18 in Garvin County, Okla. From Jan. 17, 2011, to Jan. 18, 2011, 50 seismic events with magnitudes from 1 to 2.8 on the Richter scale were recorded in the vertical well. The events began seven hours after hydraulic fracturing operations were started, with 39 events occurring within 16 hours after that time.
Why is this important? Because data confirming seismically induced earthquakes are continuing to mount. Several states are considering legislation to restrict wastewater disposal wells.
This is not one of those problems that is going to evaporate. Ways must be found to clean up flowback and produced water for reuse or to provide water for agricultural purposes. This is going to have to happen, or the industry really will be “all shook up.”
Read Scott Weeden's original version of "‘Whole Lotta Shakin’ Goin’ On’ In The Oil Patch" from January 2014.