* To sell 12.75 pct stake in Heidelberg project
* To continue as operator with 31.5 pct interest
* Shares up 3 pct in morning trading
March 5 (Reuters) - Oil and gas producer Anadarko Petroleum Corp said it would sell a 12.75 percent interest in a deepwater oil project in the Gulf of Mexico for $860 million to ensure funding until production starts in mid-2016.
Anadarko will continue to operate the Heidelberg development project with a 31.5 percent interest after the stake sale to an undisclosed party.
Exxon Mobil Corp, Apache Corp, Eni SpA and Statoil ASA own the remaining stake in the oilfield, about 140 miles offshore Louisiana. It is estimated to hold up to 400 million barrels of recoverable resources.
"Transaction makes sense to us as it provides a solid valuation for the market, sells down a portion of a long-life project in a tax efficient manner (tax-free), and covers the company's capital commitment," Wells Fargo analyst David Tameron wrote in a note to clients.
Anadarko and an Indian billionaire have launched the auction of a 20 percent stake in a Mozambique gas field that could fetch $4.5 billion, Reuters reported earlier on Tuesday, citing sources familiar with the matter.
Oil and gas production in 2013 might come in at the low end of forecasts, reflecting an oversupplied natural gas liquids market and weather disruptions, the company said last month.
Anadarko struck a similar deal last year, when a third-party partner agreed to fund $556 million of development costs to earn a 7.2 percent working interest in its Lucius development in the Gulf of Mexico.
Shares of the company rose 3 percent to $83.03 in morning trading on the New York Stock Exchange on Tuesday.