Even when all quality issues are sorted out there can still be problems. After the various issues of high and low aromatic fuels were sorted as far as engine performance goes they then discovered that the high aromatic fuels would find a leak point the others wouldnt. Easily resolved in the factory but a pain in the ass to replace connectors on fuel systems in the field.Well, there is a big difference between OIL as it comes out of the ground (called crude oil) and OIL PRODUCTS.
Crude oil can vary considerably depending on which oil field it comes from in regards to what percentage of different products you can per ton and for certain products it can make a big difference in the products also. Like 40 octane gas to 70 octane after simple distilling.
When it comes to the products they have to meet certain standards regardless of source. Going back to aviation fuel, 87 octane product is pretty much 87 octane fuel regardless of source. It not only has to pass the octane test, it needs to have a certain heat value, it needs to evaporate at a certain temperature and specified rate. It has to have a certain vapor pressure and gum residue limit. Different countries can have slightly different limits but they have to be close or the fuel won't work properly at different temperatures or altitudes. It doesn't matter if the fuel is made from coal or crude oil, it has to work in the engines desired.
Same for lubricating oil or diesel fuel. Russian diesel isn't going to be much different than German diesel.
Ships that weren't diesel ran on bunker fuel which is pretty much crude oil with some of the good stuff taken out and with most of the lumps also taken out (joke) but bunker needs to be heated to flow even at normal temperatures.
Oil products can cover quite a range and sometimes sources just use "oil" as shorthand for oil products so it can be a bit confusing.
However, aside from needing more frequent fuel filter changes, one country's Diesels should run just fine on another country's diesel fuel.