Melzer has no doubts about the oil. He calls west Texas residual oil zones, or “ROZ” in drilling lingo, the “rozapolis” because of their enormous potential. Montana, North Dakota and Wyoming are also rich in residual oil, says Vello Kuuskraa, who helped develop wells near Fort Worth in 1997 that showed the viability of hydraulic fracturing, or fracking, and unleashed U.S. fossil-fuel fever.
Unlike fracturing, in which drillers blast water, sand and chemicals into wells to shatter shale and release oil and gas, CO2-enhanced drilling induces a chemical reaction that makes oil less sticky and helps it flow from pores in the rock. CO2 costs about $35 per metric ton in west Texas, and drillers recycle it as many times as possible to dislodge more oil.
Such drilling has the potential to unlock 100 billion barrels of recoverable U.S. reserves, says Kuuskraa, president of Advanced Resources International. U.S. reserves total 222.6 billion barrels this year, the Energy Information Administration says. About one-third of Kuuskraa’s projected increase, or 33 billion barrels, would come from residual zones, augmenting the bounty that fracturing is recovering from shale rock.
“Shale oil could produce 3 million barrels a day for the U.S.,” he says. “With CO2 EOR, we’ve got the potential to do 3 or 4 million barrels a day for a long time.” That much CO2 EOR crude would have increased last year’s output by 50 percent.
Kuuskraa’s projections come with a caveat: securing enough CO2 to free the oil. Expanded CO2 EOR requires new sources of carbon dioxide, which scientists say hastens global warming. In 2009, the Environmental Protection Agency classified CO2 as a pollutant that threatens public health.
Kuuskraa estimates that the United States may need 33 billion metric tons of the gas for CO2 EOR. Three billion tons are available from such naturally occurring sources as extinct volcanoes. The rest would come from man-made sources such as power plants that create and capture CO2. Only a handful of these exist.
John Thompson of the Clean Air Task Force says creating demand for carbon dioxide is an environmental benefit of drilling residual oil. He says the zones are big enough to absorb half the CO2 from U.S. power plants over 30 years, and he advocates tax incentives for companies to expand CO2 EOR. “I hope Elliott Roosevelt makes a lot of money,” he says. “I hope other people replicate his model and take more CO2 out of the atmosphere.”
The seeming illogic of using a heat-trapping greenhouse gas to enable the pumping of pollution-spewing hydrocarbons isn’t lost on Kyle Ash, senior lobbyist for environmental advocate Greenpeace USA. He says enhanced oil recovery doesn’t move the nation away from fossil fuels or permanently bury carbon.