HOUSTON — ConocoPhillips said Friday it plans to develop a multibillion-dollar pipeline that would transport natural gas from Alaska to the lower 48 states and Canada.

The oil exploration and production company said it's "prepared to make significant investments, without state matching funds, to advance this project."

ConocoPhillips spokesman Charlie Rowton said the company's best estimate for the entire project, including the pipeline from Alaska's North Slope to Chicago, is between $25 billion and $42 billion.

The pipeline would provide an important avenue for bringing Alaska's massive stores of natural gas to U.S. markets that rely on it for heating homes and other uses. It would move about 4 billion cubic feet of natural gas per day.

The U.S. consumed about 21.7 trillion cubic feet of natural gas in 2006, according to the Energy Department.

In a statement, ConocoPhillips Chairman and Chief Executive Jim Mulva said the company hopes to work directly with the state to advance the project as quickly as possible.

"We also expect to approach other parties to explore ways through which their participation could add value to this effort," Mulva said.

Specifically, Rowton said Exxon Mobil Corp. and BP PLC would be logical participants as the project moves forward. Partnering with a pipeline company also is a possibility.

"We think it makes sense for there to be other owners," he said.

BP spokesman Steve Rinehart in Alaska said he couldn't speculate on whether the company would be interested in partnering with ConocoPhillips, but it had no intention of submitting its own bid. Rinehart added, however, "we think a successful gas project is very important."

Exxon Mobil said it had no comment.

ConocoPhillips said it is already gathering data to support the pipeline permit application.

During the initial phase of the project, Bechtel Oil, Gas and Chemicals Inc. will provide construction and design support, the company said.

Shares of ConocoPhillips rose 1 cent to $78.83 in early afternoon trading Friday. The shares have traded in a range of $61.59 to $90.84 in the past year.

Friday was the deadline for applications from companies interested in building the pipeline.

Alaska Gov. Sarah Palin began calling for applications in July and extended the deadline by two months in August after more companies began to inquire. Oil and independent pipeline companies must outline details such as the pipeline's route, the market it will serve and how it can build a pipeline and avoid cost overruns.

Palin has said the gas-line project could one day be the economic life of the state, much like oil production in the North Slope is today.

But a potential multibillion-dollar pipeline also carries implications for North America's long-term energy supply and has been widely discussed by lawmakers, energy regulators and company executives throughout North America since Palin outlined her plans in March.

Palin has long warned the state and the nation cannot afford to let the natural gas supplies — estimated at about 35 trillion cubic feet on the North Slope — sit untapped any longer.

Alaska has struggled for decades to get a deal either with North Slope producers or independent pipeline companies to build a line that could possibly run from the North Slope through Canada and into the Midwest.

A proposed deal between former Gov. Frank Murkowski and North Slope producers BP, Exxon Mobil and ConocoPhillips fell apart last year.