NEW ORLEANS (Reuters) - Rick Santorum won the Louisiana Republican primary on Saturday, CNN projected based on exit polls, adding an 11th state to his total but still trailing Mitt Romney by a wide margin in the national delegate count.

The network made the call moments after voting closed, citing Santorum's lead among voters in all income groups except for the very wealthy, who favored Romney, a former Massachusetts governor.

Santorum, a former U.S. senator from Pennsylvania, has done well in conservative states of the Deep South, winning Mississippi and Alabama earlier this month.

Saturday's primary allocated only 20 of Louisiana's 46 total Republican delegates as candidates spar for the right to take on Democratic President Barack Obama in the November general election.

(Reporting By Ros Krasny and Samuel P. Jacobs; Editing by Eric Beech)