They send you for a coupe of days to one of their operation bases. You sleep in an hotel nearby, and you won´t get much sleep as after dinner, which ends around 23:00 to 24:00 hours, they give you a manual which you must study and be able to take an exam next morning at 7:00.
During the day, they take you to the base, at which they will further explain details and general stuff about the job, and you will do some excersise with your previously assigned team, which were cool.
They do not tell you for which position they´re hiring. This means that even though have the right profile for Slb, you don´t necessarily have the profile for that specific position. They will ask you what you´re interested in and hopefully there is a similar position open.
During this recruitment process they treat you preatty well, and even though you dont get an offer it´s an amazing experience.
In my case, I got an offer 2 weeks after the recruitment process and they send me my contract about 2 months after the initial offer.