"We look at $50 to $90 on the range (for planning purposes)," said Chief Financial Officer Simon Henry in a conference call.
"I'm not sure we see it right at the bottom of that over the next 12 months, but we could certainly see it in the middle of that range," Henry said.
Brent traded on Thursday at $111 a barrel, US crude at $96.
Shell's $50-$90 range appears to be more conservative than some of its rival oil majors.
At the end of October BP Chief Executive Bob Dudley said an increasing number of industry players were measuring the profitability of projects against expectations of a $90-$100 a barrel market.
Shell Chief Executive Peter Voser said Shell uses a $4-$6 per British thermal unit to plan US natural gas projects, well above the $2.60 spot price for natural gas.
Natural gas prices have fallen sharply this year, pressured by new supply from shale gas production. They were last above $4 per BTU in September of last year.
