Occidental Petroleum Corp. and Plains Exploration & Production Co. have agreed to expand their holdings in Colorado’s Piceance Gas Basin with a $162 million asset purchase.

The purchase includes 11,500 acres with more than 800 future drilling locations and may hold reserves of up to 75 million barrels of oil. The two oil companies will split a 95 percent interest in the land assets, Plains said in a statement.

The seller was not identified.

The basin holds natural-gas deposits, which have become more enticing to energy companies as technology for extraction has advanced. The price of gas has increased as more is used for heating and to fuel power-plants.

Domestic gas futures have jumped 78 percent this year, compared to crude oil’s 41 percent advance.

Los Angeles-based Occidental and Houston-based Plains already operate in the region. Occidental bought a 50 percent stake in assets surrounding the Piceance Basin from Plains and other companies for $1.55 billion in March.

Shares in Occidental were down 2.4 percent to $88.07 in early trading Thursday.