Oil in the Middle East

As many people before me have observed the major oil-producing areas do seem to be in the lowly elevated parts of the Middle East, and most of them are near water. If this is the case though, why is there an area that crosses the Iraq border with Armenia, which on the topographical map appears to be relatively highly elevated, however is apparently one of the major oil-producing areas on the map in our book? It's also obvious on the oil map that many of the oil producing areas cross from one country into another, which is an obvious source of conflict in the Middle-East since everyone wants it for themselves.