By Kristen Hays
HOUSTON (Reuters) - A tropical depression hovering over the central Gulf of Mexico on Friday threatened to bring heavy flooding to the energy infrastructure-heavy Gulf Coast in the coming days.
Tropical depression 13, which could become Tropical Storm Lee later on Friday, has already prompted oil and gas producers to shut down platforms and evacuate workers from the offshore oil patch that provides about a third of the nation's oil production and about 12 percent of its natural gas.
The slow-moving system that has essentially parked about 210 miles south of the mouth of the Mississippi River could bring up to 20 inches of rain over southern Louisiana, Mississippi and Alabama through Sunday, the National Hurricane Center said.
Louisiana Governor Bobby Jindal on Thursday declared a state of emergency, citing the likelihood coastal and inland areas would be drenched by up to 15 inches of torrential rain within 48 hours.
Heavy, prolonged rains could pose a severe test to low-lying New Orleans and its protective levee system.
The Gulf Coast is home to 40 percent of U.S. refining capacity and 30 percent of natural gas processing plant capacity. Much of that infrastructure is in southeast Texas and near the coasts of Louisiana and Mississippi.
"They're calling for 18 to 20 inches of rain in spots over the next several days. You've got big issues," said Aaron Studwell, a meteorologist with Wilkens Weather in Houston.
Will Hinson, spokesman for Exxon Mobil Corp's joint-venture 192,500 barrel-per-day (bpd) refinery in Chalmette, Louisiana, said the plant was prepared and was operating normally.
Other refiners also said they were prepared for bad weather and were monitoring the system.
Major Gulf producer Royal Dutch Shell spokeswoman Kelly op de Weegh said on Friday the company had "minimal" production impacts, but had evacuated 500 workers and may evacuate more. Shell operates six oil and gas platforms in the Gulf.
Other producers, including BP Plc and Anadarko Petroleum Corp, were shutting all output and evacuating all workers.
Studwell said the system was about 190 miles southwest of the center of Mississippi Canyon and 75 miles south-southwest of Green Canyon, the two areas of the Gulf with the highest concentrations of oil and gas platforms.
(Reporting by Kristen Hays and Erwin Seba; editing by Jim Marshall)