(New throughout, adds background and details on PDVSA's shipping operations)
May 8 (Reuters) - State-run PDVSA ordered an oil tanker that was waiting to discharge in Curacao to divert to Venezuelan waters after ConocoPhillips introduced an order in a Caribbean court to seize its inventories and other assets in the island, according to a shipper and Reuters data on Tuesday.
The U.S. oil company has moved aggressively in recent days to attach PDVSA's assets in the Caribbean, one of its main export hubs, to enforce a $2 billion arbitration award related to the nationalization of Conoco's projects in Venezuela in 2007.
The Aframax tanker British Cygnet loaded crude at Russia's Primorsk terminal last month. It arrived in Curacao's Bullenbay terminal on Sunday, two days after at least two Caribbean courts ordered the retention of PDVSA's inventories and facilities in Bonaire, Curacao, Aruba and St. Eustatius by request of the U.S. oil company.
PDVSA has been buying U.S. and Russian crudes this year for refining at its 335,000 barrel-per-day Isla refinery in Curacao and for blending with extra-heavy oil from the Orinoco Belt, Venezuela's main producing region.
The British Cygnet tanker, which set sail for Venezuela's western coast on Monday night, follows at least nine vessels diverted since Friday from Curacao and Bonaire to Venezuela and Cuba to avoid possible seizures of tankers or their barrels, according to a PDVSA source and Reuters data.
Cargoes arriving from the Caribbean have started creating bottlenecks of vessels around PDVSA's main ports, especially Jose, Venezuela's largest terminal for crude exports, and the docks that serve PDVSA's biggest refinery, the Paraguana Refining Center, according to the data.
The Caribbean terminals affected by the court orders last year were responsible for shipping about 400,000 bpd of crude and refined products, or 24 percent of PDVSA's total exports, according to the company's internal data.
PDVSA's U.S. refining unit Citgo Petroleum also uses the Aruba terminal to discharge, store and blend Venezuelan and foreign crudes for its refineries along the U.S. Gulf Coast. (Reporting by Marianna Parraga Editing by Marguerita Choy and David Gregorio)