Marathon Petroleum says it's assessing options for the future of the largest mainland US oil conduit- the 1.2 M/bd Capline pipeline. In recent years, the pipeline, which runs from St. James, Louisiana (the delivery hub for Light Louisiana Sweet crude) to Patoka, Illinois, has seen sharp declines in shipping volumes as midwestern refiners access the growing supply of Bakken and Canadian crude to replace expensive imports via Capline.