Occidental Petroleum Corp. said Monday that it has agreed to buy $1.55 billion in oil assets from Houston oil company Plains Exploration & Production Co.

The sale is for a 50 percent interest in Plains Exploration’s Permian Basin holdings in West Texas and New Mexico, as well as a 50 percent interest in its Piceance Basin holdings in Colorado. Plains Exploration also sold $200 million worth of assets to XTO Energy Inc., a Fort Worth-based oil company.

The Permian basin holdings generate about 18,000 barrels of oil per day, with about 91 million barrels of oil in proved reserves as of the end of last year.

Los Angeles-based Occidental said the transaction, expected to close in the first quarter, will help it achieve its goal of 20 percent year-over-year growth from its combined Piceance assets.

Shares in Occidental were down 2.3 percent to $68.72 in early trading Monday on the New York Stock Exchange.