NEW YORK (Bloomberg) — Bermuda-based Weatherford International Ltd., the fourth-largest US oilfield-services provider by market value, plans to sell $500 million of 10-year global senior unsecured notes, according to a person familiar with the offering.

Proceeds may be used to repay debt, the company said today in a statement distributed on PRNewswire, which didn't specify the size of the sale.

The notes may be rated Baa1, the third-lowest investment grade, by Moody's Investors Service and an equivalent BBB+ by Standard & Poor's, said the person, who declined to be identified because terms aren't set.

Weatherford last month announced its intention to change its jurisdiction of incorporation to Switzerland.