An Oil pool is formed when a when hydrocarbons are trapped by rocks either stratigraphically or structurally. If such a trap occurs in your country, then your country will have petroleum irrespective of whether your country's neighbours have oil or not.
having said that, Venezuela has oil reserveves in the following formations:
1 Maracaibo
2 Oriental
3 Apure
4 Falcon
5 Orinoco Oil Sand belt
In the case of Saudi Arabia, however, most of the petroleum deposits are found around the Persian Gulf. There are so many countries around the same that all of them can benefit from these reservoirs.