HOUSTON, April 11 (Reuters) - At least two vessels

carrying Venezuelan crude chartered by Chevron ( CVX ) are now

stalled in Venezuelan waters due to state oil company PDVSA

canceling their export authorizations after the U.S. imposed

secondary tariffs on the OPEC member's buyers, two sources with

knowledge of the matter said on Friday.

The U.S. oil producer awaits customs paperwork to return the

cargoes to ports after PDVSA on Thursday canceled set-sail

authorizations to two of the Chevron ( CVX )-chartered vessels that had

finished loading. It also suspended a loading permit to a third

tanker, the sources said.

Under an individual license to operate in U.S.-sanctioned

Venezuela, Chevron ( CVX ) was authorized by the U.S. Treasury

Department in March to ship Venezuelan crude cargoes to the

United States until late May before suspending operations and

exports.

But PDVSA's orders might cut the deadline short.

As of Friday, the Chevron ( CVX )-chartered vessels Dubai Attraction

and Carina Voyager remained loaded in Venezuelan waters waiting

for paperwork for the cargoes' return, according to the sources

and LSEG shipping data.

The cargoes had been declared as exports to Venezuela's

customs authority, so Chevron ( CVX ) must now obtain authorization for

their return as instructed by PDVSA, the sources said.

Carina Voyager was bound for Chevron's ( CVX ) Pascagoula refinery

in Mississippi, while Dubai Attraction was scheduled to transfer

its cargo to a Valero Energy ( VLO )-chartered vessel off Aruba,

according to the data and sources.

A third vessel, the Pegasus Star, was suspended a window to

load this week, the sources added.

Chevron ( CVX ) and PDVSA did not reply to requests for comment.

Valero did not immediately respond to a comment request.

It was not immediately clear if the cargoes would be

rescheduled by PDVSA.

Chevron ( CVX ), whose joint ventures with PDVSA produce about a

quarter of the country's oil output, exported some 250,000

barrels per day (bpd) of Venezuelan crude to the U.S. in the

first quarter under its license, granted in 2022.

That license and others to European and Asian companies in

Venezuela were canceled by U.S. President Donald Trump's

administration last month as Washington accused President

Nicolas Maduro of not doing enough to curb illegal migration to

the U.S. and restore democracy in Venezuela.

Maduro's government rejects the U.S. sanctions on the

country's oil industry, in effect since 2019, saying they amount

to an "economic war."