HOUSTON, Aug 5 (Reuters) - Chevron ( CVX ) and Valero

Energy ( VLO ) are working to resume supplies of Venezuelan

crude to Valero's U.S. refineries under an agreement that was on

pause, three sources close to the preparations said on Tuesday,

following a new license granted to the U.S. oil major.

Washington in late July issued a new restricted

authorization for Chevron ( CVX ) to operate, swap oil and export crude

from sanctioned Venezuela in a policy shift following a prisoner

swap. The U.S. producer last week said it expected to resume oil

shipments this month, starting with a small volume.

As Chevron ( CVX ) waits for Venezuelan state company PDVSA to

allocate cargoes for August delivery, Chevron ( CVX ) and Valero are

negotiating details of their agreement, including resuming a

ship-to-ship operation off the Caribbean island of Aruba.

Valero's cargo transfer off Aruba could restart as soon

as this month, following mandatory inspections and vessel

contracts in negotiation, one of the sources said.

Chevron ( CVX ) and Valero did not immediately respond to

requests for comment.

In the first quarter, before Chevron's ( CVX ) license to operate in

Venezuela was revoked, Chevron ( CVX ) supplied some 50,000 barrels per

day (bpd) of Venezuelan heavy crude to Valero's refineries from

Aruba, according to shipping data.

The volume represented about 20% of Chevron's ( CVX ) total exports

of Venezuelan oil in that period, the data showed.

The supply deal is key for Chevron's ( CVX ) second largest joint

venture in Venezuela, Petroboscan in Venezuela's western region,

due to limitations in storing the heavy Boscan crude produced by

that project, which have forced output cuts in the past.