Two branches of Kyushu University in Japan are developing an advanced method for analyzing the permeability of rock in underground reservoirs that could be used to store captured CO2, the university said in a press release.
Emptied oil and gas fields or deep aquifers have been identified as potential storage sites for captured carbon dioxide, the release says. However, key to success is understanding how fluids move through the rock in such sites in order to prevent the CO2 from escaping.
Prior research on this topic has been built on fairly basic models that largely anticipate the pores in rocks will be uniform in shape and size and distributed evenly, the release says. “These techniques, and simple laboratory simulations, limit our ability to understand a broad range of potential Co2 storage reservoirs below ground,” Fei Jiang, co-author of a study published in Advances in Water Resources, said in the release.
The university’s International Institute for Carbon-Neutral Energy Research (I2CNER) and Department of Earth Resources Engineering believe they have found a better way. Researchers employed X-ray microcomputed tomography to scan rock and then merged their findings with highly specific mathematical simulations. That enabled them to create “a picture of the real displacement of water by CO2 below ground and identify the optimal conditions for CO2 storage in real rocks,” as well as to “examine the movement of fluids inside the rock at an unprecedented level of detail,” the university said.
“We were able to identify the main regime for fluid displacement inside our sandstone samples,” said lead author Takeshi Tsuji, “and because of the properties of our sandstone, we can determine which processes are most dominant in natural rocks that could be used for CO2 storage.”
Ultimately, rock from a site being considered for use as a CO2 reservoir could be studied using the Kyushu University method, helping to strengthen CCS as a means for dealing with carbon emissions, according to the release.
