WASHINGTON, March 18 (Reuters) - A U. S. plan to help control global oil prices with a swap of millions of barrels of oil from the Strategic Petroleum Reserve depends on energy companies returning oil back to the facility with high premiums in the form of additional barrels, which some traders said could deter participation.

Megan Cerullo is a New York-based reporter for CBS MoneyWatch covering small business, workplace, health care, consumer spending and personal finance topics.