The financial terms of the agreement were not disclosed.
Covering about 14,353 acres, the new leases ADL 391899, 391902, 391903 and 391904 adjoin the existing Cosmopolitan project, in which Buccaneer Energy is the operator with 25% interest and BlueCrest Energy holds the rest.
The company has offered BlueCrest Energy the ability to acquire a 75% working interest in the leases, which it believes have the potential to contain new reserves associated with the Cosmopolitan geological structure.
Cosmo is an oil and gas field located in 50ft of water in the Cook Inlet of Alaska and is in close proximity to the shoreline at Anchor Point on the Kenai Peninsula.
An independent reserve estimate last year found that the field contains an estimated 55.2 million barrel of oil equivalent (mmboe) of 2P reserves (13.8mmboe net to the company).