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EPA plans Class I permit for Nikaitchuq Deep injection wells involve pumping industrial waste into underground reservoirs; technique used extensively across Alaska By Eric Lidji Petroleum News
As Eni Petroleum works to become the fourth operator to produce oil from Alaska’s North Slope, the Italian super major is turning to a familiar strategy for disposing of the large amounts of industrial waste associated with development drilling.
Like BP, ConocoPhillips and Pioneer Natural Resources before it, Eni plans to pump millions of barrels of drill cuttings, slurry and wastewater around one mile underground beneath the offshore Nikaitchuq unit, located in the Beaufort Sea near Oliktok Point.
These “deep well injections” have become increasingly common on both the North Slope and the Cook Inlet basin over the past five years as a way to avoid the potential hazards of trucking industrial waste to a more traditional disposal site, according to Thor Cutler, with the U.S. Environmental Protection Agency.
“They are a very expensive alternative, but they’re more environmentally sound than to transport over the tundra,” Cutler said.
The EPA plans to issue a permit for Eni to drill four of these Class I injection wells at Nikaitchuq, two from a drill pad being built at Spy Island and another two from a new pad under construction at Oliktok Point. The permit would last for 10 years.
The federal regulatory agency is taking comments about the project through Sept. 15 when it plans to hold a public meeting in Anchorage on the issue.
Eni is currently spending around $1.45 billion to bring Nikaitchuq into production by the end of next year. With construction underway in the shallow waters of the Beaufort Sea as well as on land at Oliktok Point, Nikaitchuq will have the first production facilities in northern Alaska not owned or operated by BP, ConocoPhillips or Exxon.
Wells now used across Alaska State and federal governments regulate several different kinds of deep injection wells.
In Alaska, the state government is responsible for Class II wells used exclusively by oil and gas companies trying to enhance recovery by injecting salt-brine into the ground.
More than a decade ago, federal regulators fined Doyon Drilling for disposing of hazardous Class I fluids into a Class II well at the BP-operated Endicott field.
Class I wells are used by oil, chemical and pharmaceutical companies, as well as other facilities like municipal wastewater treatment plants, to pump industrial waste below known sources of drinking water. To qualify for the EPA permit, a company must prove that any water in the reservoir is too salty for drinking.
“This deep well injection is into an area that is not a potential source of drinking water in the future,” Cutler said.
As of February 2008, the EPA counted around 550 Class I wells in the United States, mostly in the Gulf Coast and the Great Lakes regions, but also across Alaska, where access to traditional landfills is scarce and traditional aboveground reserves pits are discouraged.
Although expensive, with each well costing around $3 million, the process has become more popular across Alaska over the past five years, although some Class I wells at Prudhoe Bay date back almost twenty years.
More recently, BP applied for Class I well permits at Milne Point in 2004, Prudhoe Bay in 2006 and Badami in 2007. In recent years, ConocoPhillips and Pioneer both used deep injection wells on development at Alpine and Oooguruk respectively, while Forest Oil and Unocal applied for permits on efforts in the Cook Inlet basin.
“This is a common practice,” Cutler said.
Eni plans to drill its injection wells into the Canning and Hue Shale formations, a 3,000-foot thick block of shale-rich geology located just below the Schrader Bluff oil formation.
The Canning formation sits about 3,600 to 4,200 feet underground, while the Hue Shale formation is about 6,500 feet below ground. Eni plans to pump its waste into many thin sand intervals in the two formations.
According to the EPA, reservoirs deeper than 4,300 feet below sea level are not underground sources of drinking water.
Nearly 3 million barrels Of the nearly 3 million barrels of industrial waste expected to be generated over the 30-year life of Nikaitchuq, almost half will come from drill cuttings and mud during the initial seven year development phase. Eni plans to drill up to 76 wells at Nikaitchuq.
Most of the remaining waste will come from sand slurry, wastewater from the production camps and work-over fluids and flushes used on the wells.
Eni did not apply for an additional permit to pump hazardous waste underground, which means any hazardous waste will have to be moved to an approved disposal facility.
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