According to a SkyTruth volunteer based in Brazil, the vessel involved in this week's spill is the tanker Elka Aristotle.
And according to a handy vessel traffic site she recently stopped off at "Campos Basin P38" which appears to be an FPSO in the Marlim Sul field of the Campos Basin. Check out this excellent, well illustrated and very detailed summary of the Marlim Sul field discovery and development, including the role of the P38 FPSO.
So this spill was most likely related to routine FPSO operations. Something to look forward to soon in the Gulf of Mexico.