Shell’s Canadian oil sands business is suffering a profitability squeeze because of the soaring cost of energy needed to extract bitumen from sand.

The oil company’s annual report, published yesterday, reveals that operating expenses at the Athabasca Oil Sands Project in Alberta have soared by almost 50 per cent in the two years since 2005, while output at the bitumen mining project has either remained static or declined.

Shell’s oil sands profits dipped sharply last year when a fire temporarily reduced the output of its upgrader, a refinery that converts bitumen into a synthetic crude oil. Earnings from oil sands fell from $651 million in 2006 to $582 million (£291 million), which the company attributes to lost output from the shutdown. The net production of the oil sands business, after deducting royalty payments, fell from 95,000 barrels per day (bpd) in 2005 to 81,000 bpd in 2007.

However, Shell’s filing to the US Securities and Exchange Commission (SEC), published yesterday, also shows a massive surge in the operating cost of the Athabasca project. It rose from $664 million in 2005 to $722 million 2006 and $967 million in 2007.

The burgeoning overheads in Canada emerged as Shell revealed that it had fully replaced its oil and gas output in 2007 with additional reserves. Shell’s total proven reserves were unchanged at 11.9 billion barrels of oil and gas, Jeroen van der Veer, Shell’s chief executive, said.

Excluding the effect of purchases and sales of oil-producing assets, such as the sale of part of its Sakhalin gas project to Gazprom and the buy-in of Shell Canada’s minority interest, Shell added 1.5 billion barrels of oil to its reserves last year. According to Shell, that equates to a reserve replacement ratio of 124 per cent, compared with an average for the top five oil companies of 108 per cent.

A big proportion of the extra barrels relate to gas reserves, notably in Qatar, where Shell has agreed sales contracts for liquefied natural gas, which enables Shell to book reserves. Other reserve additions include gas in Australia’s North West Shelf and the Ormen Lange gasfield in Norway.

Peter Voser, Shell’s finance director, said that overall internal cost inflation was running at 10 per cent per annum. He estimated that the operating cost of an oil sands barrel was in the range of $20 to $25 per barrel.

Shell will not reveal the development cost of its oil sands projects, including an expansion that will add 100,000 barrels per day of output, but it is likely to be close to $20 per barrel, well above the average of between $6 and $7 per barrel for the company as a whole.

Oil sands represent about 10 per cent of Shell’s proven reserves of 11.9 billion barrels and are assessed separately by the SEC, which considers oil sands to be a mining business. However, the potential resource in the ground in Shell’s acreage is 20 billion - which is not in dispute, since the reserves are close to the surface.

Separately, Shell disclosed yesterday that the US Department of Justice is investigating Shell’s use of Panal-pina, a Swiss freight forwarding company, in connection with alleged corruption in relation to customs officials in Nigeria. The Justice Department began a criminal investigation last year into illegal payments to customs agents in Nigeria and sent letters to 11 oil and oil-service firms. Shell said that it had started an internal investigation and would cooperate with the Justice Department.

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