Not positive on this but think that GCMS and maybe ICP analysis can match crude down to the specific oil field. Blending two oil fields is probably not too difficult to determine the mix. Just takes a few more seconds or minutes of computer time.
I am sure you are correct.
I should stick to things I know something about. Instead of talking out my A$$.
I miss Thackney. He was formerly our FR expert on all things petroleum related. He taught me the difference between Light Sweet crude and Heavy Sulfur crude.
He was a Petroleum Engineer. Plus he knew all about the transport of oil by tanker, pipeline or donkey.
He may have passed because I have not seen him post in many years.