There were 2 stages. A psychometric test + recorded video interview and then an assessment centre.
If you're a student, please ask your university for access to a website called 'graduates first'. It has a bunch of practice psychometric tests for every company, including Shell's. I practiced that and the same format came up. The style of test were game assessments and work personality questionnaires and extra stuff. It was a while back so I don't exactly remember.
A few weeks later, someone from Shell called me and said they liked my CV and wanted to put me through to the final stage. We discussed my interests and what roles they had available so they could assign me to a specific department.
The assessment centre was tough. It was an online interview with two employees. I was given a 30 page case study 2 days before hand which I had to fully understand and be prepared with questions. The interview was 3 hours long. The first 1.5 hours involved questions on the case study and started off with them asking me to take 20 minutes to prepare a 5 minute presentation. I was only asked the question in the interview, so I had no clue what they were going to ask within the 2 day prep I had. I prepared beforehand with a SWOT analysis which was insanely useful. They even said later they could tell I had notes which was a plus.
The second 1.5 hours of the interview involved behavioural questions. We took a short break before getting onto this part.
I received an offer 30 minutes after I finished the assessment. Following that, they worked with me to find a role that suit me best. The department I first chose didn't work out, so they were flexible and found something else that really fit. The salary is extremely fantastic for a graduate scheme
It was a total month and a half from when I first applied, but it was an easy to understand process. No messing you about
