The U.S. Environmental Protection Agency (EPA) has recommended that Oklahoma regulators enact a moratorium on oil and natural gas disposal wells in sensitive areas of the Arbuckle Formation. The agency said it is concerned that the state's response to injection-induced seismicity is both inconsistent and ineffective.
But a spokesman for the Oklahoma Corporation Commission (OCC) said it is "on the same page" as the EPA, as illustrated by the "area of interest" being staked out by the commission and its Oil and Gas Conservation Division (OGCD) since mid-2015.
EPA's recommendation for a moratorium was included in an annual end-of-year evaluation of the OCC's Class II Underground Injection Control (UIC) program. The evaluation -- conducted by EPA Region 6 in Dallas and covering the state's 2015 fiscal year, which ended on June 30, 2015 -- was part of its annual review of the UIC program, released on Sept. 22 of this year.
"Despite OCC's evolving response actions, seismicity continues to be of concern, particularly with respect to the upward trend in the number of magnitude-4.0 [M4+] and greater events through 2015," EPA said. "This trend included a record monthly number of M4+ events in November 2015 [see Shale Daily, Nov. 20, 2015; Nov. 19, 2015]."
According to EPA, until last March the OCC's response had been to focus on disposal wells located near M4+ events. At that time, the OGCD ordered more than 400 wastewater injection wells targeting the Arbuckle to reduce their disposal volumes by 40% below 2014 levels for a two month-period (see Shale Daily, March 7).
"EPA has learned that in some cases, OCC permitted restricted wells to return to normal operations and new wells authorized in targeted areas after requesting volume restrictions of existing wells," the federal agency said. "EPA has expressed concern that these inconsistencies are significantly diminishing the effectiveness of OCC's response actions."
While it commended the OCC for its actions, EPA recommended that the state take additional steps to protect groundwater from seismic activity, including making further reductions of wastewater injection volumes into the Arbuckle. But the federal agency added that ongoing seismicity indicated a link between the Arbuckle and basement rocks.
Consequently, EPA summarily recommended that the OCC "consider a moratorium on Arbuckle disposal in high seismically active focus areas. OCC should implement a policy or program changes to prevent new Arbuckle injection activities in restricted areas."
OCC spokesman Matt Skinner told NGI's Shale Dailythat EPA's annual review of the UIC program provided a "rearview mirror look" of seismic activity in the state.
"While the EPA doesn't define the terms used in the report, if we can assume the issue is stopping Arbuckle disposal in key areas -- we're on the same page," Skinner said Tuesday. "After the period covered by the annual review, we began much broader and more sweeping actions, which include well shutdowns.
"Fast forward to the most current action [in Pawnee County]. That involved the EPA directly -- Osage County was included in the OCC-designed action area -- and we worked closely with the EPA on that action. The EPA's response was to take the same action as the OCC [see Shale Daily, Sept. 13].
"As for not permitting wells in the earthquake area -- again, you have to look past June of 2015. The OCC has not permitted a new Arbuckle disposal well in an 'area of interest,' which now encompasses 15,000 square miles, in about a year."
Last month, OGCD directed 37 disposal wells targeting the Arbuckle and within a 725-square mile area to cease operations (see Shale Daily, Sept. 6). Meanwhile EPA, which has sole jurisdiction over disposal wells in Osage County because it lies within the Osage Nation Mineral Reserve, followed suit and ordered an additional 17 disposal wells to also cease operations (see Shale Daily, Sept. 8).
Since the beginning of the year, OCC has ordered operators of about 700 wastewater injection wells targeting the Arbuckle formation to cease or curtail their operations.
OGCD unveiled its Western Regional Reduction Plan, which called for a nearly 500,000 b/d reduction in wastewater injection volumes, in February (see Shale Daily, Feb. 17). It released its Central Oklahoma Volume Reduction Plan, which called for a 300,000 b/d reduction in injection volumes, one month later.