Eight refineries along the US Gulf Coast were shut down by Katrina. Refineries are pretty tough, so I think estimates of "several weeks" of shut down are exaggerated. The capacity shut down is about 10% of US total. At least two report no damage.
List of the active refineries in the area here.
Valero says down two weeks
Citgo/Exxon Chalmette reopen ""Once the U.S. authorities lift the alert we will bring the refinery back up," said Alejandro Granado, refining director for state-run Petroleos de Venezuela S.A."
DOE EIA info here
As of August 19 (the most recent data available), U.S. commercial crude oil inventories were well above the average range for this time of year. However, gasoline inventories were at the lower end of the average range, and with demand growing at a 1.6 percent rate over the most recent 4-week period, they are very low in terms of the amount of days gasoline inventories would supply. Distillate inventories remain above the average range for this time of year. Inventory data as of August 26 will be available at 10:30 am ET on Wednesday, August 31.Not a shortage of crude (so, in case you are wondering, the release from the Strategic Petroleum Reserve is mostly window dressing in my opinion). The real issue is refining capacity.