Guest – think your question may be a bit too broad and general to answer. You need to get more specific & accurate on your question. But here is try on very broad answer.
First if by Bitumen you mean asphalt product – then you are talking about general economics of vacuum bottoms/resid into either a SDAU (Solvent = C3/C4/C5 Deasphalting Unit) or a coking unit which is general margins on simple vs complex refinery and that nearly always favors coking operation except in very isolated situations & high value asphalt.
But if by Bitumen you mean Bitumen Crude that has been diluted vs Bitumen Crude that has been turned into lighter Synthetic Crude via coking operations and that is comparison of cost of the diluent required to take an 8API heavy crude up to 19+API that it takes to get into a pipeline/ability handle vs the cost of upgrade coking operation that it takes to produce the synthetic crude. The diluted Bitumen crude is called Dil-Bit and sometimes they acutally use the Synthetic crude to dilute the Bitumen crude and call it Syn-Bit or use it in mixture Dil-Syn-Bit. Most Upgrade Coking operations are in very remote areas that have little access to diluents like Naphtha/Condensate/Gas Oil/ecty which were so expensive the crude needed a +$30/Bbl when conventional crude only cost $18-24/Bbl. Once upgraders produced Synthetic crude/Naphtha/Gas Oil/Diesel ect the value dropped to price competative with conventional crude cost.
There is huge amount of literature from Canada Oil industry and from first two major players websites (Suncor uses delayed cokers & Syncrude used fluid cokers).