Earlier this week, the Texas Railroad Commission held its first "show cause" hearing under the rule amendments adopted last October to address issues related to disposal wells located in potential high-risk seismic areas. Under the amendments, the Railroad Commission has the authority to modify, suspend, or terminate a disposal well permit if it is determined that a disposal well is likely to be or determined to be contributing to seismic activity. At the June 10-11 hearing before the Railroad Commission's Hearings Division, XTO Energy Inc. was ordered to show cause why the injection permit for a Parker County (TX) well should not be cancelled and the well ordered shut-in due to an alleged connection raised by new seismic research between ongoing operation of the well and seismic activity in the vicinity. In addition to the XTO well, the Railroad Commission's order also covered a Wise County well operated by Enervest Operating L.L.C.
As covered by the North America Shale Blog last month, researchers at Southern Methodist University published an article pointing to hydraulic fracturing activities near Azle, Texas, as the probable cause of an increase in earthquakes and other unusual seismic activity in the area. Azle is located on the border of Parker and Tarrant Counties. As part of the announcement of the show cause hearing, Commissioner David Porter said, "Due to the fact that the wells were permitted prior to the Commission's rule amendments addressing disposal well activity and seismic activity, and in light of the new research contained in SMU's report, it's appropriate and necessary for the Commission to consider the operation of these wells in a fully informed manner and determine the appropriate course of action."
Andree Griffin, XTO's vice president of geology and geophysics, testified Wednesday that the quakes were naturally occurring. The Fort Worth Basin, where the gas-rich Barnett Shale is located, "has had several episodes of movement and reactivation of faults" over a roughly 600-million-year period, Griffin said. Griffin also testified that the larger earthquakes in the area had started approximately 2.5 miles below the wastewater injections, which occurred approximately 7,000 feet below ground.
The Railroad Commission's show cause hearing on the Enervest well will take place next week.
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