Offshore drilling contractor Seadrill Ltd. said Wednesday that it received a commitment from an oil company for new contracts that could be worth up to $4 billion for three ultra-deepwater drilling units slated to be used in the Gulf of Mexico.

The combined package involves two drillships under construction and a third unit currently in operation, Seadrill said. The value of the commitment includes mobilization fees for the newly constructed ships.

Seadrill did not identify the oil company. Operations are scheduled to begin next year in the Gulf of Mexico.

The Hamilton, Bermuda, company said that it hopes to expand its fleet and operations in the Gulf in the future. Seadrill owns at least 66 units for operations in shallow to ultra-deepwater regions.

Shares of Seadrill rose 77 cents, or 2 percent, to $38.56 in morning trading. In the past 52 weeks, the price has ranged between $24.68 and $42.34 per share.