Researchers Study Impact of CO2 Sequestration on Subsurface Microbial Communities

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Microorganisms living in depleted oil reservoirs continue to produce methane under high-concentration carbon dioxide (CO2) conditions caused by CO2 storage, according to a joint study released on June 13, 2013, by Japan's National Institute of Advanced Industrial Science and Technology (AIST), INPEX Corporation, which is an international oil and gas exploration company, and Newcastle University in the UK.

Depleted oil reservoirs are candidate sites for carbon capture and storage (CCS), a process of capturing huge amounts of CO2 released from power plants and the like, and sequestering the CO2 underground. Meanwhile, microbial communities that produce methane are widely distributed in oil reservoirs around the world, holding the promise of a new source of energy in the form of this methane (natural gas).

AIST and INPEX previously reported the world-first discovery that microbes in a depleted oil reservoir in Yabase Oil Field in Akita (northern Japan) convert acetate to CO2 and methane. Researchers this time collected water and crude oil samples from this oil field, and set up laboratory conditions mimicking the in situ oil reservoir conditions and those with high CO2 concentrations resulting from CCS. The comparison showed that methane production by microbes continued in high CO2 conditions, although its pathways were drastically changed by the CO2 injection.

The study highlighted the efficacy of geomicrobiological studies-the combination of earth sciences and microbiology-in the development of CCS technology.