Whiting Petroleum Corp. (WLL) opened an offer to exchange all of its outstanding, unregistered senior notes, the company said June 3.

The 6.25% senior notes are due 2023 and will be exchanged for new, registered but otherwise identical notes.

The new notes will not have securities law transfer restrictions and registration rights will not pay additional interest.

The exchange offer is scheduled to expire on July 1, unless extended. Valid tenders must be made before the expiration date.

The Bank of New York Mellon Trust Co. NA is the exchange agent.

Whiting Petroleum Corp. is based in Denver and produces domestic oil, natural gas and NGL.