Don't be confused about the tests. Aptitude test will be for those who are gunning for graduate trainee positions.It has 3 sections or so. They are verbal reasoning, numerical reasoning and diagrammatic tests.
Then the skills tests are for the experienced candidates. It is purely based on your acclaimed field.For example if u are going for an electrical engineering post, be ready to know much about transformers, electrical devices and so on.
In all time is of essence.

If u find this helpful, don't hesitate to appreciate it. God be with u.

@Elon

Thanks for you input with respect to the Mobil Apt/Skills test. This will really help all dem folks that have been lookin for clues or some sort of expo
Thumbs up man

Elon, thanks for your clue, but you are not exactly correct. The test, whether graduate or experienced position, is in TWO parts: the aptitude and the skills.
the aptitude is in three sections; verbal(shl-true, false, cannot say), numerical(shl-graphs and tables) and diagramatic(you could check GMAT pg;299-304, 2007. check also thesame examples in 2005 and 2006).
The skills part which is also compulsory, is in your field of study. for the chemical engineers, you could brushup your calculations in distillation columns, heat transfer, thermodynamics, pressure measurement(bourdon gauge), calculations involving venturi meter, orifice meter and pitot tube.see also material balance calculations, refrigeration cycle and different design standards e.g 'ASME' CODE, SECTION VIII. See also the theories of mass transfer.

you should also not forget to pray. my brodas i must warn; NO BE BEANS O!
ALL THE BEST.

Kaliphman Thanx a million times. God be with us all.

If I must ask.why would EM have  aptitude test for folks with over ten years of  proven experience continously in Oilfield.

Other parts of the world ,  your direct bosses and HOD's ask your some technical questions and your are hired.

Please I will appreciate geniune answer if possible.