SINGAPORE -
* Qatar has set its January retroactive official selling price (OSP) for its Marine crude at $67.20 a barrel, down 85 cents a barrel from the previous month, a pricing document seen by Reuters showed on Tuesday
* That sets the OSP differential for Qatar Marine at $2.91 above Dubai quotes, down 25 cents a barrel from a month ago
* Qatar also set its January Qatar Land crude OSP at $67.70 a barrel, down $1.20 a barrel from the previous month, the document showed
* That puts Land crude's OSP premium to Dubai quotes at $3.41 a barrel, 60 cents lower than the previous month
(Reporting by Shu Zhang; editing by Jason Neely) ((shu.zhang@thomsonreuters.com; +65-6870-3549; Reuters Messaging: Twitter @shuzhang4))