Oil Sands Energy Security Act of 2011 - Amends the Energy Independence and Security Act of 2007 to repeal the requirement that any federal agency procurement contract for an alternative or synthetic fuel, including those from nonconventional petroleum sources, for any mobility-related use (except research or testing) specify that lifecycle greenhouse gas emissions associated with the fuel must, on an ongoing basis, be less than or equal to such emissions from equivalent conventional fuel produced from conventional petroleum sources.