Unocal to Sell Several of Its U.S. Oil Fields : Energy: The firm targets $350 million in “non-strategic” assets. Four hundred jobs will be eliminated.

Narrowing the focus of a company restructuring announced last week, Unocal Corp. said Wednesday it will sell or turn into joint ventures $350 million in “non-strategic” assets--mostly the working U.S. oil fields of its exploration and production group.

In the process, the company expects to eliminate 400 jobs.

This brings Unocal halfway to its goal of trimming $700 million in assets and increasing after-tax cash flow by $200 million a year, ultimately to reduce the company’s debt by $1.5 billion in the next five years.

Unocal has been saddled with substantial debt--now $4.7 billion--since successfully resisting a 1985 takeover attempt by Texas entrepreneur T. Boone Pickens.

The company’s energy resources group, from which the trims will be made, searches for and produces crude oil, natural gas and geothermal energy worldwide. While most of the cuts will come in its U.S. operations, the group will also drop plans to explore 100 of its 150 most promising geologic sites around the world, focusing on the 50 most likely to produce a major new energy find.

Unocal spokesman Mike Thacher said that one project not likely to be dropped is the company’s participation in a proposal to develop the potentially giant Azeri oil field in the Caspian Sea in Azerbaijan.

“I don’t think we would back off from that,” Thacher said Wednesday.

Unocal will also reorganize some U.S. offices, including moving the Oklahoma City and Midland, Tex., offices of the energy resources group to Houston. Specific job cuts have yet to be decided.