OSLO (Reuters) - A carbon dioxide store beneath the floor of the North Sea remains tight and is not leaking the greenhouse gas 13 years after storage began, Norwegian oil and gas company StatoilHydro said on Thursday.
Companies and scientists have pinned big hopes on carbon capture and storage (CCS) as a future way to curb greenhouse gas emissions and combat global warming, but worries linger that stored carbon dioxide could leak out.
"New seismic data from the Utsira formation in the North Sea indicate that the carbon dioxide being pumped into it is not leaking out, but is spreading through the structure as expected," StatoilHydro said in a statement.
StatoilHydro and its partners in the Sleipner gas field have pumped more than 10 million tons of carbon dioxide (CO2) into a sandstone formation below the sea bed since autumn 1996, the company said in a statement.
StatoilHydro strips the CO2, the main greenhouse gas blamed by scientists for global warming, from the field's gas well stream and injects it into the sandstone reservoir.
"StatoilHydro conducts extensive monitoring and control of the carbon dioxide in the sub-surface store, and collects four-dimensional seismic data every other year," the company said, adding that data from the 2008 had now been analyzed.
"The seven geophysical measurements conducted to date show a stable trend, with the carbon dioxide spreading upwards from the injection site and slowly through the rock," it said.
The dispersion speed remains the same as in 2006, and the monitoring has found that the gas remains in the formation with no leakage to the surface, it said.
Twelve years of data and seven surveys "show that long-term carbon storage in sub-surface geological formations represents a secure approach," Eli Aamot, head of StatoilHydro's new energy and ideas research program, said in the statement.
(Reporting by John Acher, editing by Anthony Barker)
