Oil and gas companies and the helicopter operators that support them are preparing to evacuate offshore rigs in the Gulf of Mexico as tropical storm Gustav bears down on the region. Royal Dutch Shell, the largest producer in the region, said it would start evacuations today. Gustav is stalled over Haiti, but U.S. forecasters see it moving through the Gulf during the next several days and intensifying into a hurricane. They project it could become a Category 3 or 4 hurricane, with winds of 96-135 kt, as it nears landfall anywhere from Florida's Panhandle in the east to southeast Texas in the West. Friday, Aug. 29, marks the third anniversary of Hurricane Katrina, which devastated the Gulf and much of that coastal region. For related news