Over on memri.org they've posted numerous translations of the Islamist agenda, and it's exactly that, get rid of the House Of Saud and take over the oil (though that's really secondary to reestablishing the Caliphate).
First, though, they have to get rid of us, because they know we'd protect the oil and the Sauds.
Assuming they can get us out of their way (and they not only assume it but believe it as prophecy), they'll then take Constantinople and Rome, which apparently is another part of the prophecy in the Koran. Then all of Europe, which they actually believe is theirs because they conquered it (almost) once before.
Israel is rarely mentioned, they evidently believe its a foregone conclusion they'll get it back.
Finally, right now the Islamists are having a little debate about attacking the House Of Saud, the consensus is "why bother" until America is dealt with.