ROYAL Dutch Shell has signalled it may withdraw from much of the North Sea and cut more jobs in the area in the wake of the planned takeover of BG after sustaining massive losses amid the crude price plunge.

The oil and gas giant was dragged $6bn into the red in the third quarter by the cost of hefty write downs it made after deciding to withdraw from exploration in the Alaskan Arctic and to shelve a huge Canadian oil sands project.

Led by chief executive Ben van Beurden, the company also slashed the valuation of its US shale acreage reflecting its view that oil and gas prices could remain low for some time.

Having announced plans to cut 6,500 jobs globally in response to the slump in the crude price, Shell said payroll costs remain a key area of focus as it looks to cut costs.

Shell did not say how the economy drive will impact on its North Sea operations run from Aberdeen. It has cut 500 North Sea jobs since August last year.

But finance chief Simon Henry signalled the firm will complete a big shake up of its North Sea operations following the planned $70bn (£45bn) takeover of BG, which has a big presence in the area and an operations base in Aberdeen.

The review will have implications for jobs in the combined operations.

Asked how the North Sea will fit in the enlarged operation, Mr Henry underlined Shell’s enthusiasm for the big new projects it is developing West of Shetland with BP.

He said Shell has good gas assets off England. However, the company will be looking hard at its portfolio off north east Scotland where many assets have been onstream for years.

“At the top and the bottom the North Sea is good,” said Mr Henry.

“In between the assets are in general terms mature, relatively late in their life cycle. We have had some good exploration success recently but the question for us was and remains at what point in their life cycle should we be considering whether these assets are best operated and monetised in the hands of others.”

The comments will likely stoke fears about the future prospects for Shell’s older fields. There are already many North Sea assets up for sale.

Mr Henry said jobs numbers will be under scrutiny across Shell as the group pursues its “grow to simplify” strategy.

Noting that wages account for 35 per cent of cost base said: “We are looking very closely at our establishments i.e. the number of people we employ and where we employ them and how we do the work that we do.”

Mr Henry added: “We have been reducing our footprint, the amount of activity and the number of people we have in Aberdeen and focused on the North Sea in recent years and I can’t give as of today a clearer view about where we go or how far we go but we will be looking when we bring the portfolios together with BG at the microcosm of grow to simplify.”

Shell said the deal to acquire the gas-focused BG Group remained on track for completion early next year, as it awaits regulatory approvals from China and Australia.

"The underlying performance does give us confidence to capture the significant value that is available in the BG combination," Mr Henry said.

Shell recorded $8.2 billion one-off charges in respect of its upstream exploration and production operation in the third quarter.

The bill included a $2.6 billion write-off due to Shell’s decision to withdraw from the Alaskan Arctic following disappointing drilling results. The company recorded a $2 billion charge for the Carmon Creek oil sands project in Canada, which it suspended on Tuesday. It also booked $3.7bn impairment charges to reflect cuts in its long-term oil and gas price outlook. Some $2.3bn related to US shale.

Shell’s upstream oil and gas production division made a quarterly loss of $8.6bn, its first in years.

The company noted oil prices had averaged $60 per barrel over the last year, down from $115 in June last year.

The downstream refining and marketing division benefited from weak prices to run refineries more profitably and its profits rose 46 percent, to $2.6 billion.

The group made $1.8bn profit before one-offs, compared with $5.8bn in the same period last year.

"It's a rather messy set of results, but it's what I expected given some of the portfolio steps they have taken and it cleans up the balance sheet in advance of the BG merger," said Jason Gammel, oil and gas equity analyst at Jefferies.

Italian rival ENI also announced a huge hit from weak oil prices on Thursday, reporting a net loss in the latest quarter, while French group Total fared better than expected and raised its production forecast.

Shell maintained the third quarter dividend at 47 cents per share.

Royal Dutch Shell A shares closed down 26.5p at 1711.5p.