Tenaris(a HUGE oilfield tubular supplier) is giving courses on edX on the following
Intro to OCTG - Oil country tubular goods, basically pipes for drilling and oil production. Very basic but it's the backbone and iconic to the oilfield.
Intro to running pipe down wells - How the above is used.
Introduction to Steel - From the sounds of it, it's probably concentrating on OCTG metallurgy.
I highly recommend you check it out if you're interested about oil. As of now, week 1 is done for OCTG but the other two will start in a few weeks.
https://www.edx.org/school/tenarisuniversity