HOUSTON, Sept 24 (Reuters) - Tropical Storm Helene was

expected to turn eastward on its track through the Caribbean and

into the Gulf of Mexico, increasing the threat of high winds and

heavy rains to Cuba and Florida but lessened the risk to U.S.

offshore oil production, forecasters said on Tuesday.

The storm was moving through the Caribbean and expected to

enter the Gulf of Mexico and become a hurricane by Wednesday,

potentially rising to a major hurricane with 115 mph (184 kph)

winds on Thursday, the National Hurricane Center said.

Its current track takes it along the west coast of Florida

toward a landfall on the state's panhandle later this week. That

path lessens the risk to oil producing regions in the central

Gulf of Mexico, meteorologists said.

U.S. offshore producers have shut-in 16% of Gulf of Mexico

oil and 11% of natural gas output, the offshore regulator said

on Tuesday. The region accounts for 15% of U.S. oil and 2% of

natural gas production.

"For the central Gulf this is a low- to medium-risk type

situation because of the eastern track of the system," said DTN

meteorologist Kevin Mahoney. But he added, "this is a very

rapidly developing system," with a potentially large wind field.

Shell, the first Gulf of Mexico oil producer to

shut in oil and gas production this week, said it was restoring

output at a platform that is about 200 miles (320 km) southwest

of New Orleans.

"With a shift in forecast track, we are beginning the

process of restoring production at Stones," the oil major said.

Its output at another platform further east in the Gulf, called

Appomattox, continues to be curtailed, it said.

Other oil producers evacuated offshore workers and scaled

back operations as NHC forecasters called for the second major

hurricane in two weeks to appear in the U.S. Gulf of Mexico.

Besides Shell, producers BP, Chevron ( CVX ), and

Equinor ( EQNR ) have withdrawn some offshore staff, and

several have paused some oil and gas production ahead of the

storm's arrival.