HOUSTON, July 6 (Reuters) -

The U.S. Coast Guard warned of possible Texas port closures

from Corpus Christi to Houston because of Hurricane Beryl, which

is expected to make landfall by Monday morning south of Port

Lavaca.

Port closures could bring to a temporary halt shipments

of crude oil to refineries and motor fuels from those plants.

Shell Plc ( SHEL ) completed the evacuation of workers

from its Perdido production platform in the U.S.-regulated Gulf

of Mexico ahead of the approach of Tropical Storm Beryl, the

company said on Friday night.

Production on Perdido was shut prior to the evacuations.

Shell said it also evacuated workers from the Whale platform,

which is due to start production later this year.

Gibson Energy ( GBNXF ), which operates a large oil terminal

in Corpus Christi, said operations were continuing, but it would

take further steps depending on the forecast.

The latest forecast would put Corpus Christi on the dry

side of the storm where the lowest winds and least rain could be

expected. But Beryl could still bring gale-force winds to the

port, which is why the Coast Guard would shut it.

Most of the northern Gulf's offshore oil and natural gas

production is east of Beryl's forecast track.

U.S. Gulf of Mexico offshore production of about 1.8 million

barrels per day accounts for about 14% of total U.S. crude

output, according to data from the U.S. Energy Information

Administration. Any impact on supplies could push up prices of

U.S. oil and offshore crude grades.

Oil major Chevron Corp ( CVX ), among the biggest U.S.

offshore producers, said on Friday that production from its

operated assets remained at normal levels. It said it had

evacuated nonessential personnel from some of its Gulf of Mexico

facilities.