Foreign companies working to develop some of Venezuela’s most prized oil fields are asking to be compensated with crude as a way to recover hundreds of millions of dollars in unpaid cash owed to them, a person with direct knowledge of the request said.

The money is owed by Venezuela’s state oil company to partners such as Spain’s Repsol SA and India’s Oil & Natural Gas Corp., the person said, asking not to be named as the matter is private. One of the companies is owed $500 million, the person said. Output at the Carabobo and San Cristobal fields in the Orinoco heavy oil belt, meanwhile, is trailing targets.