Patent US 3,974,062

A refinery process is described for converting desalted full range crude oils and syncrudes derived from coal, shale and tar sands. The process involves mixing and reacting the full range heavy oil feed with a low molecular weight carbon-hydrogen fragment contributor such as methanol or C.sub.2 -C.sub.5 olefins in the presence of a fluid zeolite cracking catalyst comprising mordenite.