CO2 more efficient than water for fracking
In the US, hydrocarbon production is booming since the previous decennium thanks to this technique. Coal for electricity production is mainly replaced by gas, not by renewable energy
Hydrofracking is highly controversial. It changes the soil’s structure and causes seismic activity. It also uses large amounts of water. Moreover, the potentially dangerous chemicals mixed with the water could contaminate the soil and drinking water.
The idea to use CO2 to reduce the environmental impact has been studied for years. After lab tests, researchers of the Chinese scientific Academy and the Chinese oil University in Beijing have now also done real-world tests. They used five wells in the Nort-Chinese oilfields of Jinlin.
“To our great satisfaction, CO2 managed to extract 4 to 20 times more oil than water”, say the authors of the report published in the American magazine Joule. CO2 does a better job at fracturing rocks.
“These real-world results show that fracking using CO2 is an important and more eco-friendly alternative to water fracking”, they add. The direct influence will be visible in dry areas where frackers have to bring water by trucks.
The researchers argue that the technique could be used to stock CO2 underground. CO2 is the main human-produced greenhouse gas. Many climate experts propose actively extracting it from the atmosphere as one of the objectives to fight global warming.
But the idea to inject CO2 into the ground to extract products that, when combusted, will emit CO2 again might not seem very useful. Hannah Chambers of the University of Edinburgh says the study doesn’t include an analysis of the general impact on worldwide CO2 emissions. It might, therefore, be premature to see CO2 fracking as a solution.