Carbon-storage experiment shows no leakage
An international team of scientists including SFU geochemist and groundwater expert, Dirk Kirste, have shown that carbon dioxide (CO2) can safely be stored underground inside depleted gas reservoirs without leaking.
The results of the team’s extensively monitored experiment in the Otway basin near Melbourne, Australia were published last month in the Proceedings of the National Academy of Science.
Working with the non-profit Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) the researchers extracted CO2 from one well and injected it in a well a kilometre away to a depth of two kilometres where it filled the depleted gas reservoir.
“We showed no leakage was detected,” says the Vancouver native who earned his PhD at U. of Calgary and worked in Australia for six years before becoming an SFU assistant professor of earth sciences in 2006.
“Governments can set up regulatory frameworks for assessing and monitoring leakage of future CO2 storage facilities based on the knowledge we obtained from this study,”
Carbon capture and storage in underground reservoirs, known as carbon sequestration, is an key strategy for global greenhouse gas reduction and is already mandatory in some jurisdictions.
“Our predictive models of reservoir filling fit well with the experimental results, which means we can apply these models in other places with confidence,” says Kirste.
He adds there are several dozen sites in Western Canada where both C02 and hydrogen sulfide gas are being injected into depleted gas fields.
Kirste was responsible for the monitoring and the geochemical modelling of fluids deep in the reservoir and monitoring drinking water aquifers near the surface.
His work involved obtaining samples at relatively high pressure and bringing them to the surface without chemically altering them on the way up, which is a tricky process.
“Carbon dioxide forms carbonic acid in water and it reacts with surrounding rock minerals meaning the storage mechanism can change with time” he says.
A consortium of Australian universities, government agencies and industry partners funded the CO2CRC Otway Project.