Tullow Oil has suspended work at a project offshore Guinea as its license partner faces a regulatory investigation.

A US probe into Hyperdynamics Corp. means UK and Irish-listed Tullow, which had planned to start drilling a deepwater well by 1 April, is unable to meet its contractual obligations. The company “cannot proceed with its activities on the license until these issues are resolved,” Tullow spokesman George Cazenove said.

Hyperdynamics’ shares have plummeted since news of the investigation. Both the US Department of Justice and the US Securities and Exchange Commission are probing Houston-based Hyperdynamics over the acquisition and retention of exploration rights in Guinea.

Tullow, the operator of the project, joined the concession in 2012 by acquiring 40% from Hyperdynamics, which now has 37%. Tullow agreed to pay $27 million in cash to Hyperdynamics to cover past exploration costs and as much as $200 million for future expenses, it said at the time.

“Tullow hopes for a speedy resolution of these issues and looks forward to continuing operations,” Cazenove told DI. Korea National Oil Corp.’s Dana Petroleum unit also is a partner in the venture.

Offshore