The Alberta government named several major Canadian and international energy companies that have leases that may be affected by a new conservation plan unveiled Tuesday prohibiting oil sands development in some areas.

The list includes Imperial Oil Ltd. (IMO), which is majority owned by Exxon Mobil Corp. (XOM), Norway's Statoil Ltd. (STO), Canadian Natural Resources Ltd. (CNQ) and Cenovus Energy Inc. (CVE).

The Alberta government said it plans to set aside more than 7,700 square miles of land in the northeastern oil sands region for conservation that would preclude oil sands development on part of 10 leases held by energy companies.

The government said oil sands companies would be compensated for their costs in purchasing and developing the canceled leases.

Cenovus Energy confirmed Tuesday that part of its Borealis oil sands lease may be affected by the government's conservation plan, but not the part that is currently planned for development.

Cenovus has applied to develop a 35,000 barrel-a-day oil sands plant in the Borealis area, but spokeswoman Rhona DelFrari said the project doesn't appear to be affected by the government's conservation plan.

"We have a lot of land in northern Alberta, so it's looking like the section that may be impacted by this is not the area that we are planning to develop in the near future," DelFrari said. She said it's not yet clear how much of Cenovus's booked oil sands reserves would be affected by the government's decision. Because Cenovus hasn't surveyed the resource on all of its oil sands property, company reserves may not be affected at all.

A Statoil spokesman said the company is studying the plan and didn't have an immediate comment.

Representatives of Imperial Oil and Canadian Natural Resources weren't immediately available to comment.

Other companies that could be affected include fledging oil sands producers Athabasca Oil Sands Corp. (ATH.T), Alberta Oilsands Inc. (AOS.V), Southern Pacific Resource Corp. (STP.T), Perpetual Energy Inc. (PMT.T) and Sunshine Oilsands Ltd.

David Pryce, a vice president for the Canadian Association of Petroleum Producers, an industry group, said more compensation should be available for companies that would see their leases canceled.

"Companies have booked value for reserves that are there, and that has been reflected in their share prices," he said.

-By Edward Welsch, Dow Jones Newswires; 403-229-9095; edward.welsch@dowjones.com