Royal Dutch Shell profits fell 15pc to $6.1bn (£3.8bn) in the third quarter, dented by lower oil and gas prices and a writedown of US shale gas assets.

Excluding one-off items, earnings came in at $6.6bn – a 6pc decrease on last year, but beating analysts’ consensus of $6.3bn.

Shell raised its dividend for the quarter by one cent per share, to 43c per ordinary share.

Peter Voser, Royal Dutch Shell chief executive, said: “Our earnings were driven by lower oil and gas prices, and lower chemicals margins, which offset the benefits of our operating performance, underlying growth in oil and gas production, and higher results in Integrated Gas and Oil Products.”

He said that energy markets remained “volatile” and there was a “difficult industry environment”.

Shell’s headline $6.1bn profits – which are reported on a ‘current cost of supply’ basis, stripping out changes to the value of the inventory – were knocked by a net $432m charge from one-off items, compared with a net gain of $245m in the third quarter of 2011.

This included a $354m charge for writing down older, more expensive shale gas assets in the US as the price of gas in fell.

Other charges included a $329m tax charge due to UK decommissioning relief changes.

Shell also made a net charge of $134m in its downstream division reflecting “legal and environmental provisions”.

Charges were partially offset by gains from asset sales.

Oil and gas production fell 1pc to 2.98m barrels of oil equivalent per day (bpd), with liquids production down 5pc but natural gas production up 4pc.

Excluding the impact of asset sales and exits and the impact of security issues onshore in Nigeria, underlying production volumes role 1pc.

Underlying earnings in the upstream exploration and production division fell 10pc to $4.9bn.

In the ‘downstream’ refining and marketing division, underlying earnings fell 4pc to $1.7bn as improved refining margins and operating performance were more than offset by lower earnings from Chemicals and from marketing and trading.