HOUSTON — Warren E. Buffett hasn’t shown much interest in oil stocks in recent years, but that changed on Tuesday when his company, Berkshire Hathaway, committed $10 billion to help Occidental Petroleum compete in a bidding war for Anadarko Petroleum.

Occidental is hoping Mr. Buffett’s reputation as one of the world’s most successful investors will bolster its proposal and financial position relative to Chevron, a company four times its size. At stake is a commanding position in the Permian Basin, the world’s most productive oil field, which straddles Texas and New Mexico.

Only a couple of weeks ago, Chevron’s proposed $33 billion acquisition of Anadarko looked like a done deal. But on Monday, Anadarko’s board said it was considering Occidental’s bid, which is roughly 20 percent higher than Chevron’s.

Should Occidental acquire Anadarko, Berkshire would invest $10 billion in new preferred shares that have an 8 percent annual dividend.