Oil Reserves - OPEC Countries

OPEC Countries

There are doubts about the reliability of official open reserves estimates, which are not provided with any form of verification that meet external reporting standards.

Since a system of country production quotas was introduced in the 1980s, partly based on reserves levels, there have been dramatic increases in reported reserves among OPEC producers. In 1983, Kuwait increased its proven reserves from 67 Gbbl (10.7×10^9 m3) to 92 Gbbl (14.6×10^9 m3). In 1985–86, the UAE almost tripled its reserves from 33 Gbbl (5.2×10^9 m3) to 97 Gbbl (15.4×10^9 m3). Saudi Arabia raised its reported reserve number in 1988 by 50%. In 2001–02, Iran raised its proven reserves by some 30% to 130 Gbbl (21×10^9 m3), which advanced it to second place in reserves and ahead of Iraq. Iran denied accusations of a political motive behind the readjustment, attributing the increase instead to a combination of new discoveries and improved recovery. No details were offered of how any of the upgrades were arrived at.

The following table illustrates these rises.

The sudden revisions in OPEC reserves, totaling nearly 300 bn barrels, have been much debated. Some of it is defended partly by the shift in ownership of reserves away from international oil companies, some of whom were obliged to report reserves under conservative US Securities and Exchange Commission rules. The most prominent explanation of the revisions is prompted by a change in OPEC rules which set production quotas (partly) on reserves. In any event, the revisions in official data had little to do with the actual discovery of new reserves.

Total reserves in many OPEC countries hardly changed in the 1990s. Official reserves in Kuwait, for example, were unchanged at 96.5 Gbbl (15.34×10^9 m3) (including its share of the Neutral Zone) from 1991 to 2002, even though the country produced more than 8 Gbbl (1.3×10^9 m3) and did not make any important new discoveries during that period. The case of Saudi Arabia is also striking, with proven reserves estimated at between 260 and 264 billion barrels (4.20×1010 m3) in the past 18 years, a variation of less than 2%, while extracting approximately 60 billion barrels (9.5×109 m3) during this period.

Sadad al-Huseini, former head of exploration and production at Saudi Aramco, estimates 300 Gbbl (48×10^9 m3) of the world's 1,200 Gbbl (190×10^9 m3) of proven reserves should be recategorized as speculative resources, though he did not specify which countries had inflated their reserves. Dr. Ali Samsam Bakhtiari, a former senior expert of the National Iranian Oil Company, has estimated that Iran, Iraq, Kuwait, Saudi Arabia and the United Arab Emirates have overstated reserves by a combined 320–390bn barrels and has said, "As for Iran, the usually accepted official 132 billion barrels (2.10×1010 m3) is almost one hundred billion over any realistic assay." Petroleum Intelligence Weekly reported that official confidential Kuwaiti documents estimate reserves of Kuwait were only 48 billion barrels (7.6×10^9 m3), of which half were proven and half were possible. The combined value of proven and possible is half of the official public estimate of proven reserves.

In July 2011, OPEC's Annual Statistical Review showed Venezuela's reserves to be larger than Saudi Arabia's.