Sour crude is extremely nasty. Has H2S, water, emulsion, it’s acidic. Sour crude contains everything from asphalt based material, gas oils, diesel, jet, naptha (gasoline), along with butane, propane, and ethanes, not to mention all the debris. Raw crude is not going to run in your car. Problem with refining sour crude is it eats metal. Refinery’s need to be set up to be able to handle the acidity and remove the sulfur. Also need to be able to process the asphalt material (coking). There’s several types of crude oil, they all produce or favor different products but contain almost everything just in various amounts. Sweet crude is much lighter and contains more lighter materials (very easy on equipment to refine) Syn crude is mainly gas oil type material. I may know a little bit about refining..