I worked at Royal Dutch Shell full-time (More than 3 years)
Shell has an excellent engineering training program
limited job security when oil prices drop
The process took 4+ weeks. I interviewed at Royal Dutch Shell.
Two online tests, followed by an in person interview, then an in person interview at Shell Recruitment Day. All in all pretty straightforward, really focus on their assessment. The 1:1 is all according to the books and everything is pretty much pre-planned out. Definitely prepare well for an assortment of questions involving specific things you have done in the past.