Carbon dioxide proposed as alternative fracking fluid

The findings the Chinese Academy of Sciences and China University of Petroleum (Beijing) suggest that the new fracking method could double as a way of storing captured atmospheric CO2. Their results are published in Joule.

Fracking extracts resources from unconventional reservoirs in which a fluid - usually water mixed with sand, foaming agents, biocides, and other chemicals - is injected into the rock, causing fractures that release the resources within. Of the approximately 7-15 million litres of fluid injected, between 30 to 50 per cent remains in the rock formation.

"We chose CO2 fracturing from a range of options because the process includes multiple benefits,” said Nannan Sun, a researcher in the Shanghai Advanced Research Institute at the Chinese Academy of Sciences. “However, we were still lacking a fundamental understanding of the technology, which is greatly important for its further development and deployment."

According to the researchers, benefits of CO2 fracturing include eliminating the need for a substantial water supply (making fracking viable in arid locations), reducing the risk of damage to reservoirs (which occurs when aqueous solutions create blockages in the rock formation), and providing an underground repository for captured CO2.