The Norwegian Petroleum Directorate (NPD) has cut its resource estimate for the Barents Sea by 11% because of poorer-than-expected reservoir properties.
The research report said that estimated recoverable resources of the Barents Sea have dropped to 910 million from 1.03 billion cubic metres of oil equivalent.
In addition to poorer reservoir properties, costs related with the development and distance to market were also factors in the estimate reduction, down from the previous figure released in 2007.
NPD said that it would be difficult to achieve the 5 billion barrels reserve growth target set for 2005-15 for Norway's continental shelf. It now assumes that about 75% of the growth in reserves must come from fields already in operation.
The research study, released on 1 September, said that a rise in natural gas exports will partially counterbalance a 10% drop in oil output in the period to 2013.
Oil output is likely to average 1.91 million barrels per day in 2009,and will decline in 2013 to 1.62 million bpd, the report said.