A comprehensive study of Plains Exploration & Production Co.’s Inglewood oil field in southern California’s Los Angeles basin found no adverse effects from two hydraulically fractured test wells.
Emphasizing that every basin has unique characteristics and concerns, Daniel R. Tormey, who led the study by Cardno ENTRIX of Los Angeles for Plains E&P and the Los Angeles County Department of Regional Planning, said, “I believe this is the first study to comprehensively look at the effects of fracing.”
The peer-reviewed October 2012 study quantified 14 different categories of physical and environmental effects of two specific frac jobs at the existing oil and gas field in Los Angeles County’s Baldwin Hills area, Tormey said at a Sept. 12 Washington, DC, briefing.
The wells were vertically drilled, but used higher water pressures common in modern frac jobs, he noted during the briefing cosponsored by the American Petroleum Institute and the US Chamber of Commerce’s Institute for 21st Century Energy.
Tormey and his study partners, Megan Schwartz and Molly Middaugh, found unique conditions in their study area that might not necessarily apply elsewhere. “When you take a close look, the LA basin pops out as the exact opposite of rural Pennsylvania, where so many people have their own private water wells,” he explained. “Two thirds of the water used in the LA basin comes from the Colorado River or the Sierra Mountains in northern California.”
They still had to measure drinking water because of concerns residents raised after seeing a homeowner set fire to water from an indoor tap in the documentary movie “Gasland,” Tormey said. “Facts have a longer row to hoe than fear,” he observed.
Not a source
Groundwater beneath the 1,000-acre Inglewood oil field, which Standard Oil discovered in 1924 and Plains E&P has operated since December 2002, is not a drinking water source but must meet that standard, according to the study.
“Routine tests by the water purveyor show the community’s water supply meets drinking water standards, including the period of high-rate gravel packs and conventional hydraulic fracturing as well as the first high-volume hydraulic fracture in September 2011,” it said. Tormey said about 20 groundwater monitoring wells there have been taking measurements from various depths for about four years.
“Apart from arsenic, which is naturally high [in LA basin groundwater], the analyzed constituents meet drinking water standards,” the study said. “Before-and-after monitoring of groundwater quality in monitor wells did not show impacts from high-volume hydraulic fracturing and high-rate gravel packing.”
To study ground movement and seismicity, Tormey and his associates did microseismic and vibration monitoring and used data from a nearby California Institute of Technology accelerometer. “The microseismic intensity was not sufficient to induce seismicity,” he said. “Where it occurred, it was linked to produced water injection.”
Tests conducted before, during, and after fracing and high-rate gravel packing showed no effects on the wells’ steel and cement casings, the study said. Plains E&P has an ongoing well integrity test program under way at the field, it added.
“Methane analyzed in soil gas and groundwater, as well as carbon and hydrogen isotopic rations in methane at the field, did not show levels of concern,” the study continued. “There was no indication of impacts from high-volume [fracing] or high-rate gravel packing.”
The study also found no problems with induced earthquakes, noise and vibration, air emissions, or community health. But Tormey warned that similar conclusions should not necessarily be expected elsewhere. “This was a precise study at a specific formation,” he noted. “When we move further away from it, some findings no longer apply. But more studies of this type will reveal some commonalities which will be useful.”
Tormey said the study was successful because the researchers began by asking people in the area what they wanted to know and listened to their concerns. “Some of the questions took us in directions we felt were unnecessary,” he said. “But responding to them turned a meeting we expected to be volatile into one that was much more civil. The way in which this study was conducted worked out well.”
Asked following Tormey’s presentation whether the study could be a model for others in places where unconventional oil and gas production are bringing activity to areas where it hasn’t been before, Erik Milito, API’s upstream operations director, agreed that it would depend on what residents want to know.
“Other companies in the industry are participating in studies already,” he told OGJ. “The goal will continue to be producing factual information to help state and local leaders make the best decisions for their citizens.”
Contact Nick Snow at email@example.com.