Mon May 11, 2009 5:33pm EDT

* Termination date is May 30

* Talks so far unsuccessful

HOUSTON, May 11 (Reuters) - Ensco International Inc (ESV.N), which had one of its drilling rigs seized by Venezuela in January, said on Monday it plans to terminate that contract unless it is paid or an agreement is reached by May 30.

The Dallas company said recent talks with Petrosucre, a unit of Venezuelan state oil company PDVSA, were not fruitful so it has filed a termination notice with the company.

In January 2009, Ensco suspended drilling operations after Petrosucre failed to pay past-due invoices. In response, Petrosucre seized the rig and restarted drilling with its own employees.

At the time, Ensco said it was owed $35.5 million.

The company said another one of its rigs under contract with Chevron Corp (CVX.N) off the coast of Venezuela and is being operated by Ensco personnel.

PDVSA faces growing complaints from contractors and service companies of unpaid bills amid a tumble in oil prices. That slide has pinched the finances of the state oil company, which also bankrolls leftist President Hugo Chavez's social programs. (Reporting by Anna Driver; Editing by Andre Grenon)