Last checked at 
By Kristen Hays
HOUSTON, Oct 3 (Reuters) - Oil and gas companies in the Gulfof Mexico started shutting in production on Thursday and wereevacuating some workers as Tropical Storm Karen moved toward theU.S. Gulf Coast.
Anadarko Petroleum Corp said it halted production atits Neptune platform, with capacity to produce up to 14,000barrels per day of oil and 23 million cubic feet per day ofnatural gas.
The company was also evacuating workers not essential toproduction from Neptune and other platforms, including thenatural gas-only Independence Hub, with capacity to produce upto 1 billion cubic feet of gas per day.
The Independence Hub is at the easternmost part of the Gulfwhere oil and gas producers can operate, about 185 miles (297km) southeast of New Orleans. It is located in a Gulf area knownas the Mississippi Canyon, which is home to much of the basin'senergy infrastructure, including two of BP Plc's Gulfplatforms.
The National Hurricane Center expected the storm to movethrough Mississippi Canyon toward the Gulf Coast betweenLouisiana and the Florida Panhandle. The NHC said the stormcould strengthen into a hurricane before making landfall.
The Gulf accounts for about 19 percent of U.S. daily oilproduction and about 6 percent of daily natural gas output,according to the U.S Energy Information Administration.
BP said on Thursday it was continuing evacuations of someworkers, but no production had been shut. ConocoPhillips, whichoperates a single platform far west of Mississippi Canyon, saidon Thursday it did not expect any impact from Karen.
In the Gulf Coast cash gasoline market, differentials surgedabout 3.00 cents per gallon on storm concerns, traders said.
"All storm hype," a Gulf refined products trader said on therise in differentials, which came despite a 1.85-million-barrelinventory build last week in the well-supplied region.
Onshore, a crude distillation unit at Chevron's Pascagoula, Mississippi refinery with capacity of 210,000 bpdwas shut early on Thursday, market intelligence service Genscapesaid, though the company did not confirm the stoppage or say ifit was storm-related.
Other operators, including Royal Dutch Shell - thebiggest oil producer in the U.S. Gulf - and Hess Corp,said they were monitoring the storm, but had not begunevacuations.
An official from Mexico's state-run producer Pemex has said the company was closely monitoring the situation, butalso had not ordered any offshore or onshore evacuations at anyinstallations.
