Here is something that I have been looking for here at OD and found it here; http://money.cnn.com/2005/09/16/news/economy/katrina_pipelines.reut/index.htm
Never done this befor so I hope it works.
"An estimated 35 percent of the crude oil now shut in by Katrina damage "can't go anywhere," Burton said, referring to pipelines and onshore refineries."

So that's 35% of 842091 BOPD (the shutin as of Sep 15), which is 19.6% of GOM production.