BOULDER, Colo., Oct. 28 (UPI) -- Just about every possible method of crude oil recovery has been used at one time or another over the past 100 years in central Wyoming's huge Salt Creek field.
When the first producers began extracting petroleum at the end of the 19th century, they actually used mining methods to bring the riches to the surface -- which is to say they dug for it.
Since then, oil producers have drilled about 4,000 wells into Salt Creek's roughly 40 square miles north of Casper, Wyo. The field is thought originally to have held about 1.7 billion barrels of oil, of which about 700 million barrels have been extracted from the main pay zone -- there are 12 geological layers capable of producing oil.
After a century or so of activity, Salt Creek is not what might be called an aesthetically appealing sight. Even the sagebrush seems to have fled in disgust from the constant pecking of the grasshopper rigs located at closely spaced intervals. Salt Creek escaped the notoriety bestowed years ago on an adjacent field, a naval petroleum reserve called Teapot Dome, which inspired a scandal in the administration of President Warren G. Harding in the early 1920s.
Though it might look more like a Superfund waste-management poster project than bold experiment, Salt Creek's ugliness could turn out to be a virtue, and it holds the potential to become an oil-production effort that even environmental activists could endorse.
Anadarko Petroleum Corp., the current owner of the field, is planning to inject carbon dioxide into Salt Creek to enhance its oil production, hoping to pull out an additional 150 million barrels.
"We're not disturbing any new ground," Rick Robitaille, Anadarko's western division manager of public affairs, told UPI's Blue Planet. "And we're projecting when we're done, we will sequester 25 million to 30 million tons of CO2, and leave it in the ground. That's 30 million tons of greenhouse gas that won't be vented to the atmosphere."
The idea of increasing production from old oil fields is not new. The primary oil and gas production technologies of the past typically recovered only about one-third to one-half of the oil in place. Secondary and tertiary recovery methods, as they are called, can add to the recovery percentage -- but only if the price is right.
That "right" price first appeared in the early 1970s, when the Organization of Petroleum Exporting Countries -- better known as OPEC -- began charging more for a large share of the world's oil. The rise in prices encouraged producers to try to get more of the remaining oil out of U.S. fields.
First-generation, enhanced-recovery techniques injected water into the ground to flood the old fields, recovering an additional 10 percent or so of the reservoir.
CO2 flooding works differently.
"Our project is 'missible,'" Robitaille said. "Oil and water don't mix. When you put water in a field, it pushes the oil through the formation to the producing well. But the CO2 mixes with the oil molecules. It tends to flush more of the oil out of the reservoir rocks," he explained. "It also requires the combination and quality of oil, the right porosity in the reservoir rocks to allow the CO2 to move through the reservoir."
Part of the Bush administration's energy policy is to attempt to lease more western public lands to oil and gas producers, many of which are the last remnants of wilderness that conservationists would like to see set aside for other uses, such as wildlife habitat, recreation and watersheds. Because the U.S. population has shown little inclination to reduce its petroleum use under either party's governance, the pressure to lease public lands is becoming more intense.
Not so far from Salt Creek, for instance, in western Colorado, environmentalists charge that, win or lose in Tuesday's election, the administration plans to lease 15,000 acres for oil and gas development within areas being considered by Congress for wilderness designation.
"Not only has this Administration refused to provide protection for these special places while they are considered for wilderness designation, it is clearly targeting those very same areas for oil and gas development," said Pete Kolbenschlag of the Colorado Environmental Coalition. "If these areas are opened to drilling, roads, and industrial activity, their wilderness character will be lost forever. Colorado's future wilderness is threatened as never before."
Projects like Anadarko's recovery attempt at Salt Creek show some promise of reducing this pressure.
"I do think it's very positive," Kirk Koepsel, northern plains representative of the Sierra Club, told Blue Planet. "Sierra Club has always said we should increase productivity of our existing fields, and not constantly look for new areas to develop. The natural values of the Salt Creek area have long ago vanished. It's a pretty industrial landscape."
One of the major environmental issues in new oilfield development, for instance, is construction of new roads, which slice wildlife habitat. No new roads are needed at Salt Creek.
Land-use issues aside, the Salt Creek project's big advantage could be its potential to take greenhouse gas emissions that otherwise would be released into the atmosphere and sequester them underground.
According to Robitaille, Anadarko has spent between $60 million and $80 million to build a 125-mile CO2 pipeline to Salt Creek from Exxon's Shute Creek gas-processing plant in west-central Wyoming.
CO2 has been an unwelcome byproduct of Exxon's natural-gas production at Shute Creek. Before the Anadarko project, Exxon had been venting the gas into the atmosphere, where it adds to the potential for holding in heat.
Sequestering greenhouse gases has become one of the hot technology topics in the global-warming debate.
Robitaille said Anadarko is looking for additional CO2 volumes to pump into Salt Creek, including the possibility of capturing them from coal-fired powerplant emissions.
"There is a growing interest in applying this technology in the region," he said.
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