Study seeks CCS benefits of extracting brine

THE UK’s Energy Technologies Institute (ETI) is funding research for a project looking at the benefits to CCS of extracting brine from storage reservoirs.

The £200,000 (US$280,000) project – which will be carried out by Heriot-Watt University in the coming nine months – will see researchers use models to develop a cost-benefit analysis of producing brines from potential stores.

The oil industry pumps naturally-occurring brine from reservoirs along with the oil it produces. This, along with seawater, is commonly reinjected into wells to control reservoir pressure and fluid flow.

“This project will investigate the potential to do the reverse,” says Heriot-Watt researcher Eric Mackay “– produce brine to prevent the pressure increasing during CO₂ injection. This will reduce the risk of leakage, increase the amount of CO₂ that individual wells can inject and increase the storage capacity of the whole system – potentially by a factor of three to four times.”

This could mean fewer wells at fewer sites are required to store the same amount of CO₂, reducing costs of appraising, drilling, operating and monitoring storage sites. This will help build confidence among future operators and investors of CCS operations.

A spokesperson for ETI told The Chemical Engineer that the desk-based study will use existing field-based models and generic models along with data from an earlier ETI project that led to the development of the UK’s principal storage screening database – CO2Stored. This estimates the capacity and injectivity for 550 stores identified off the UK’s coast.

Partners on the project include consultancy Element Energy and Durham University.