The impact of underground injection wells on aquifers is not well understood, but the state continues to allow their proliferation.
By Aaron Cantu, Capital & Main
This story is produced by the award-winning nonprofit Capital & Main and co-published here with permission.
Throughout 2020 and early 2021, California issued more than 300 permits to oil and gas companies for new underground injection wells — an intensive form of oil production and wastewater disposal.
But the actual number of new injection wells is likely higher, owing to the state’s opaque approval process that has drawn scrutiny from auditors and environmentalists. Some of these undercounted wells may be polluting groundwater used for public drinking and agricultural purposes, according to regulatory filings reviewed by Capital & Main.
The impact of injection wells on groundwater in California is understudied, regulators say. The California Geologic Energy Management Division (CalGEM), which issues the permits and regulates the industry, is currently the subject of a lawsuit alleging the division issued permits for wells without required environmental reviews.
Environmentalists say it’s another contradiction in the state’s energy policy, which seeks to position California as a leader in reducing greenhouse gas emissions while at the same time issuing hundreds of permits for injection wells — an energy-intensive and pollution-heavy form of hydrocarbon production — and prolonging society’s dependence on fossil fuels.
USGS and State Water Board studying groundwater impacts
Following a 2013 law, state and local water regulators have worked with the United States Geological Survey (USGS) to assemble criteria for monitoring groundwater in the vicinity of oil and gas wells. At least two assessments, one in Ventura County and another in Kern County, showed petroleum-related gases or fluids migrating into important aquifers.
In statements to Capital & Main, the oil and gas industry claimed that these assessments had not proven that injection wells negatively impacted public water supplies. Yet the full story is more complicated: The state’s nine regional water boards, which are overseen by the State Water Resources Control Board, have only recently begun looking at the issue, and in some cases oil companies have resisted regulatory actions or framed inconclusive findings as a victory.
Most of the injection well permits issued by CalGEM were for oil production through cyclic steam, waterflooding or steamflooding, all of which involve pushing pressurized water into a layer of diatomite — a fossilized slice of earth containing hardened oil — and allowing the water to loosen the oil until it can be pumped out. Injection wells can be as deep as 5,000 feet and account for 60% of all produced oil in California, where much of the remaining supply is difficult to access by more conventional means.
A related kind of well involves injecting water produced while extracting oil back into an underground aquifer to dispose of it. To do this, an aquifer must be exempted from federal protections by the EPA — a trend that accelerated under former President Trump’s administration. Injected water is also used to increase overall oil production in more than 95% of the state’s injection wells. It’s often mixed with toxic chemicals.
The impact of injection wells on groundwater is still coming into focus, according to John Borkovich, a supervising engineering geologist who oversees the state’s groundwater monitoring programs for the state water board. Although state law requires the well path be sealed with corrosion-resistant materials, damaged wells can leak.
“What we’ve seen is that the disposal of produced water has been of the most concern to the [regional] water boards,” Borkovich told Capital & Main. In the case of cyclic steam and other forms of steam or water injection to extract oil, he added, “as far as groundwater contamination associated with it, we’ve just barely scraped the surface with the USGS studies on looking at that particular issue, [so] it’s premature to make a statement one way or another.”
A state moratorium on new high-pressure fracturing projects and wells, issued in January 2020 by Gov. Newsom’s administration, still allows for approvals of injection wells operating at lower pressures. Some high-pressure cyclic steam wells that existed prior to the moratorium also received rework permits during 2020 or 2021, according to a CalGEM spokesperson.
The moratorium came in response to above-ground oil spills, but did not mention potential risks to groundwater.
Faceoff in Ventura
One of the more public scraps over water pollution has unfolded in Ventura County. A USGSreport from 2019 found that petroleum-related gases in the vicinity of injection wells on the Oxnard Plain were migrating into an overlying aquifer that supplies water to 700,000residents, prompting the county to institute new regulations.
A follow-up USGS study released in January found that water samples with the highest concentrations of thermogenic gases were near oil wells and large volumes of injected water, but couldn’t determine the source of the gases due to a small sample size.
In an emailed statement to Capital & Main, the California Independent Petroleum Association said that the study “definitively states that there is no evidence of oil operations impacting groundwater aquifers.” But environmentalist Liz Beall with Ventura-based environmental group Climate First: Replacing Oil & Gas emphasized the study’s limitations.
“Here in Ventura, the Oxnard Plain is our major hotbed of cyclic steam injection wells, and if you look at the ground there, it looks like Swiss cheese because of decades of drilling,” said Beall. “We’re counting on our state agencies to step in where the county can’t.”
Big oil faces tough questions, concerns over fluids migrating into rivers and canals
The vast majority of new injection well permits issued by CalGEM last year and early 2021 were for Kern County, where thousands of wells — active, inactive, and plugged — dot the landscape. It’s also where the Central Valley Regional Water Quality Control Board is currently grilling two of the largest oil producers in California over their injection wells’ impacts on groundwater.
In one patch of the Kern River Oil Field, Chevron is attempting to add seven additional injection wells as part of a “non-expansion” permit package application. The company received a quarter of CalGEM’s new well permits in 2020 and 2021 through early March, including 157 for underground injection wells — 23 of which were for the Kern River field.
In a letter to CalGEM dated February 17, an engineer with the Central Valley Regional Water Quality Control Board outlined several concerns the regulatory body had with the non-expansion permit package assembled by Chevron, including two active cyclic steam wells that had failed the state’s regulatory tests.
“Staff is concerned with potential surface expressions occurring and fluids migrating to the Kern River and/or the nearby canal,” said the letter, noting that wells were within several hundred feet of the water bodies.
Clay Rodgers, a Fresno-based assistant executive officer who oversees the Regional Board’s Oil Field regulatory program, said Chevron wouldn’t be able to move forward with developing the new wells until the board’s questions were resolved.
“Usually, when we have wells where there are mechanical testing integrity issues, we’ll ask, ‘Has it been fixed so it’s not a potential conduit of fluids into zones that were not intended to receive what has been injected?’” Rodgers told Capital & Main.
A spokesperson for Chevron said that the company had “provided responses to the Water Board’s initial concerns and questions and looks forward to continuing to work through the permitting process to support continued safe operation in the Kern River Oil field.”
Other filings indicate that local water bodies near Kern County oil fields may have already been polluted by injection wells.
Last August, the Central Valley water board sent an order to Aera Energy demanding technical reports for dozens of injection wells across three oil fields — Lost Hills, North Belridge and South Belridge — it suspects are leaking fluids into the Tulare aquifer, including underground sources of drinking water. A USGS study documenting the pollution noted that tainted water could be found underground as far as 1,800 feet away from the suspected problem wells.
Aera, a joint operation of ExxonMobil and Shell, received 596 permits for new wells from CalGEM last year, more than any other company, including 71 for injection wells.
Rodgers, who was involved in the study, said he and his team believed that Aera’s wells were “a potential source for the constituents that USGS was seeing, and [felt that] an order was appropriate in order to determine exactly what the contribution is, if any.”
Aera requested a delay of the order, which the regional board mostly denied.
In a statement to Capital & Main, a spokesperson for Aera said that while the company was working with regulators, it did not “believe that the [USGS] study provides conclusive evidence that there is contamination of the groundwater,” and accused the study’s authors of making “unfounded conclusions to link oilfield operations to well-known data that says oil field fluids are present in oilfields, because they are just that — oil fields.”
Patrick Pulupa, executive officer of the Central Valley Regional Water Quality Control Board, defended the board’s investigatory authority as “very broad.”
“Are the discharges staying where they are supposed to stay in portions of that aquifer that we don’t expect to be used as a source of drinking water?” Pulupa said. “If those discharges are migrating, I think we’re going to force the issue requiring remedial action, we could potentially issue a clean-up and abatement order, but our first recourse would be to go to CalGEM and say, ‘Your order prescribes a certain area where [discharges] are supposed to stay, if discharge isn’t staying there, you gotta do something about it.’”
CalGEM has recently come under fire for its injection well regulatory process, which critics say is too lax and undercounts the total number of active injection wells.
An audit released last November of CalGEM’s permitting process for injection wells by the state’s Department of Finance found that the agency allowed oil companies to add clusters of new injection wells without subjecting them to full environmental reviews, in one case allowing an operator to expand a project by 640 acres and 400 new wells — including 100 injection wells.
Known as “non-expansion” projects, wells approved under these arrangements may not be reflected in the total number of permits awarded by the state for new wells, meaning that the total number of injection wells in California is likely higher than the official number maintained by CalGEM.
“Most times these projects go through and get approved without very much oversight or questioning about what the dangers of these expansions are going to be,” said Hollin Kretzmann, an attorney for the Center for Biological Diversity who is suing the state for failing to properly regulate new oil wells.
Jacob Roper, a spokesperson for CalGEM, told Capital & Main the department had implemented all “major” recommendations from the audit. Roper also said CalGEM had discontinued the use of placeholder permits, which it had used to approve injection well projects without geologic or engineering reviews.
A separate review of CalGEM’s injection well permitting process being conducted by experts at the Lawrence Livermore National Laboratory is expected to deliver its findings in “a matter of months.”
Potential ban in the works
Meanwhile, a bill introduced in the state Senate in February would lead to a complete ban on injection-based oil and gas production, including hydrofracturing and cyclic steam by 2027, and waterflooding and steamflooding by 2035. The legislation would also institute a 2,500-foot “health protection zone” between wells and homes, schools and other facilities, a long sought-after goal of environmental justice advocates.
One of its sponsors, State Sen. Scott Wiener, said the impact of injection wells on water tables was “certainly one” of the impacts he was concerned with.
“We know there have been a number of studies showing that oil extraction, particularly these harsh varieties, have real health impacts on surrounding communities — we know oil extraction usually happens in lower class and working class communities, communities of color, and they cause serious health impacts in addition to having impacts on air and water.”
But Wiener noted the bill would not ban the practice of underground produced water disposal — which could be a major culprit of groundwater pollution by oil and gas activities.
From 2008 to 2018, the industry produced 1.3 trillion gallons of water in California via oil and gas extraction; as of the second quarter of 2017, 81% of produced water was injected back underground, according to a report from the environmental group Earthworks.
According to Pulupa, the Central Valley water board director, injecting produced water may pose less of a threat to groundwater supplies than other methods, such as disposing of it inunlined pits, but its full impact is still murky and presents risks.
“If you dispose enough of the produced water, it might migrate toward the valley floor, which is not a drinking water supply as of now, but certainly is water used for agricultural purposes,” Pulupa said.
Roper, the CalGEM spokesperson, said the agency is in discussions with the state water board to design a truncated environmental review process for new injection wells that have typically not been subject to them because they’re part of so-called non-expansion projects.
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