Earnings after taxation dropped to $26.59 billion (19.62 billion euros) in 2012, compared with $30.92 billion in the previous year, Shell revealed in its annual results statement.

However, net profits rose 3.0 percent to $6.7 billion in the three months to December, from $6.5 billion last time around. Production also grew by 3.0 percent to 3.41 million barrels of oil equivalent per day over the same period.

On a more upbeat note, Shell said that adjusted net profits, stripping out gains or losses from fluctuations in the value of its inventories, jumped 13 percent to $7.29 billion in the fourth quarter.

Total revenues meanwhile increased by 2.0 percent to $118.05 billion in the same period.

"Shell is on track for plans we set out in early 2012, despite headwinds last year," chief executive Peter Voser said in the earnings release.

The group added: "Shell will continue the strategic drive to grow its upstream businesses, with ongoing selective investment in downstream."

Shell expects to make $33 billion in net capital investment this year, with new projects lined up for Nigeria, Kazakhstan, Iraq and the Arctic.

"Although the economic outlook remains uncertain for some of Shell's key markets ... the prospects for long-term growth in global energy demand remained unchanged, driven by rising world population and improving standards of living in developing countries," Shell said.