A report by environmental group Clean Water Action (CWA) has called into question injection well practices in Texas, asserting that state regulators have failed to live up to a 1982 agreement with the U.S. Environmental Protection Agency (EPA). The Railroad Commission of Texas (RRC) disagrees.
In 1982 Texas was granted primary oversight authority of its Underground Injection Control (UIC) Class II injection well program. Oil fields that were producing at the time were given blanket exemptions to inject into aquifers. However, "it remains unclear whether EPA Region 6 or the Railroad Commission has a list of oil fields that were considered exempt," CWA said in a report released last week.
The type of injection wells in question can be used to enhance oil recovery; they can also be used for oil and gas wastewater disposal.
"The lack of an original list of aquifer exemptions is problematic for two reasons. First, without the necessary list from 1982 there is no way to decipher which wells were permitted to inject into exempted aquifers," CWA said. "Second, there is no way to prove that subsequent injection wells [that] were permitted outside the boundaries of the original oil fields did not need an aquifer exemption."
The report cites correspondence from the RRC to CWA that says the commission has "never received any aquifer exemption requests..."
CWA said that "in practice, this would mean that the Railroad Commission has never permitted an injection well into an aquifer containing less than the [threshold] 10,000 [milligrams per liter total dissolved solids (TDS)].
"While possible, Clean Water Action is skeptical of this conclusion due to the vast number of injection wells in Texas, and the relatively common occurrence of injection into relatively high-quality aquifers in other states." CWA cited California as an example of this.
The CWA report cites fiscal 2015 year-end data from EPA that says Texas has 54,811 Class II injection wells, which is more than any other state. Citing March 2016 correspondence from RRC to EPA, CWA's report said, "In March 2016, the Railroad Commission provided proof of at least two injection wells permitted into USDWs [underground source of drinking water] without an aquifer exemption and admitted there were more wells in a 'handful' of oil fields where the water is deemed of drinking water quality (under 10,000 mg/l TDS).
"Additionally, EPA stated that the Railroad Commission said it would be an 'administrative burden' to identify all wells potentially permitted without the required aquifer exemption."
RRC spokeswoman Ramona Nye said the commission is in compliance with the April 1982 agreement with EPA acknowledging exemptions for all existing production zones and disposal wells at the time. "This program protects drinking water and in fact, the EPA's Fiscal Year 2015 End-of-Year Evaluation of the Commission's UIC program recognizes the commission's 'outstanding enforcement monitoring program' for Class II injection wells," Nye said in an email to NGI's Shale Daily. "In addition, even EPA has been quoted as saying it, 'does not believe these operations will pollute any water wells in the area based on the permit restrictions.'
"The commission will use grant funding to research and verify that Class II injection well permits issued after April 23, 1982 do not authorize injection into underground sources of drinking water in zones that were not approved by the EPA on April 23, 1982."