The service giant is selling $1.1 billion in convertible senior notes due 2021 that will be repaid with cash or equity at Weatherford's discretion.
Underwriters have the option to buy another $165 million to cover over-allotments.
Weatherford concurrently launched a tender offer to retire up to $1.1 billion of its existing senior notes due between 2017 and 2020.
The size of both the tender and convertible note offerings was upsized from an initial $1 billion to $1.1
