By Marianna Parraga and Sarah McFarlane
HOUSTON/LONDON (Reuters) - Four tankers carrying over 2 million barrels of U.S. crude are stuck at sea and cannot discharge at a Caribbean terminal because Venezuela's PDVSA has not yet paid supplier BP Plc (BP.L), according to two sources and Thomson Reuters vessel tracking data.
The cargoes are part of a tender Petroleos de Venezuela [PDVSA.UL], known as PDVSA, awarded in March to BP and China Oil. The deal was to import some 8 million barrels of West Texas Intermediate (WTI) crude so Venezuela could dilute its extra heavy crudes and feed its Caribbean refineries.
While three cargoes for this tender were delivered in April, seven other vessels, including BP's four hired ones, are waiting to discharge, leaving up to 3.85 million barrels of WTI in limbo.
PDVSA did not immediately respond to a request for comment.
The company's cash crunch, which also affected its oil imports late last year, have added to a backlog of tankers since March due to malfunctioning loading arms at Jose, Venezuela's main crude port.
PDVSA initially offered to pay for the imports with Venezuelan oil, but negotiations for those swaps failed as the proposed loading windows and crude grades did not work for BP, a source close to the talks said.
Amid low crude prices, declining exports and a brutal recession at home, PDVSA has since 2015 delayed payments to suppliers. As a result, service firms including Schlumberger (SLB.N), Halliburton (HAL.N) and Petrex have curtailed operations in the OPEC country.
The payment delays are also raising questions about who will pay for demurrage, or the daily costs for delays. Three of the BP tankers have been anchored for over 30 days.
As China already lifts Venezuelan crude as part of broader oil-for-loans deals, its companies have agreed on swaps for this tender, the sources said.
Issues with loading arms to receive tankers at Jose port have doubled wait times for shippers since March.
PDVSA said in a statement that installation of replacement equipment in the port's southern dock were successfully concluded on Tuesday.
Some 30 dirty tankers are currently waiting around PDVSA's ports in Venezuela and Curacao.
PDVSA has become one of the largest buyers of U.S. crude since last month even with a narrow arbitrage that makes most exports unattractive, analysts have said, but payment delays could stymie its bid to continue imports.
(Reporting by Marianna Parraga in Houston and Sarah McFarlane in London, with additional reporting by Alexandra Ulmer in Caracas; Editing by Cynthia Osterman, Toni Reinhold)