One thing you wouldn't think oil companies would be short on is carbon dioxide pollution. But when trying to get every last drop of black gold from old wells, the greenhouse gas comes in handy.
Injecting CO2 into an oil well causes some of the gas to dissolve in the oil. The oil then swells, which allows it to be more easily extracted.
The up side? Whatever CO2 is left underground is kept there. According to the oil industry, more CO2 goes into the ground then eventually comes out and into the atmosphere via the oil.
Texas' Denbury Resources Inc. has been collecting CO2 from Jackson Dome, an old volcano in Mississippi. But now the company is in the market for human-made emissions.
Next month, Denbury will finish almost 250 miles of a "green pipeline" that will stretch 320 miles from Plaquemine, Louisiana to Houston, Texas. Sometime next year, purchased compressed CO2 will flow from Dow Chemical's ethylene oxide plant to Denbury's Hastings oil field.
Just how much does a ton of CO2 cost? Depending on oil prices, about $10, reports New Scientist's Helen Knight.
Wyoming's Anadarko Petroluem may also be buying 6 million tons of the gas from an ExxonMobile plant for their oil recovery operations.
"For every barrel of oil extracted, we replace it with an equivalent volume of CO2," [says Denbury president Tracy Evans].
By weight, though, more gas is pumped in than is released by burning the oil displaced. A barrel of oil emits around 0.4 tonnes of CO2, but around 0.6 tonnes will be buried to get it out. "By the time enhanced recovery is uneconomical, we'll have sequestered 30 to 50 per cent more CO2 than that barrel of oil will give off," Evans says.
Denbury also plans to purchase CO2 from a syngas plant in Plaquemarine and eventually build another pipeline through the Midwest.
Image: Denbury Resources, Inc.
Via: New Scientist
This post was originally published on Smartplanet.com