I do not know any details about Iraq but overall in order to learn a petroleum system you have to recognize a few things.
1- Source rocks and their ages
2- Capacity of the source rocks to produce oil and gas and the timing of their maturity
3- Timing of the structures so they should be later earlier than the migration of oil
4- Availability of petroleum migration pathways
5- Sealing lithologies, their extent and properties
6- Reservoir rock properties and extent
7- traps; structural highs, faults and stratigraphic traps
These are not yes/no questions, there would be a wide variety of information related to this and the task is to study and integrate all the information and make the best guess. Risking of the play fairways and ranking of the leads is also important!
hope this helped