New tool monitors CO2 injection underground

Aerial view of the study site at In Salah.
Google Earth / Image © CNES / Astrium
Date:6 July 2016 Author: Nikky Knijf Tags:, , , , ,

CO2 injection into the ground has been found to play a large role in meeting the reduction targets set by the Intergovernmental Panel on Climate Change.

Earlier this year an article published by Science News linked increased earth shudders in the central USA to the injection of CO2 and other watery waste fluids into the ground. The implications of increased CO2 levels in the earth have not been fully researched, but to this end, researchers at the École Polytechnique Fédérale de Lausanne (EPFL) have developed a tool that simulates the CO2 injection and to evaluate what impact the injection might have on the host rock.

An evaluation of the ground surrounding the In Salah gas-fired power plant in Algeria has shown the ground has risen by 16 millimetres over the last 54 months. The researchers have credited this rise in surface height to the CO2 injection into a deep aquifer. It is believed excessive CO2 injection could potentially fracture the surrounding bedrock. To this the EPFL researchers developed a tool to asses how much CO2 this area could safely accommodate.

A researcher at EPFL’s Chair “Gaz Naturel”-Petrosvibri and co-author of the study, Li Chao, said: “When CO2 is injected into a deep aquifer, sometimes thousands of meters underground, it is much cooler than the surrounding rock and compressed to the point that it occupies 500 times less volume than it would in the atmosphere. Because of its temperature, its pressure, and the volume it occupies, it interacts with the surrounding rock. This can deform the rock, causing geological instabilities, and in the worst case, fracture the cap-rock that seals the aquifer, allowing the gas to escape to the surface.” He adds: “Our simulation results came very close to matching the satellite observations.”

Find how Iceland pumps CO2 back into the ground, here.

Source: EPFL

Image credit: Google Earth / Image © CNES / Astrium

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