<P> The proven oil reserves in Saudi Arabia are the second largest in the world, estimated to be 268 billion barrels (43 × 10 ^ m) (Gbbl hereafter), including 2.5 Gbbl in the Saudi--Kuwaiti neutral zone . They are predominantly found in the Eastern Province . These reserves were the largest in the world until Venezuela announced they had increased their proven reserves to 297 Gbbl in January 2011 . The Saudi reserves are about one - fifth of the world's total conventional oil reserves, a large fraction of these reserves comes from a small number of very large oil fields, and past production amounts to 40% of the stated reserves . </P> <P> In 2000, the US Geological Survey estimated that remaining undiscovered oil reserves in Saudi Arabia had a probability - weighted average of 90 Gbbl . </P>

Where are most of saudi arabia's oil fields located