Iran’s crude oil reserves and production

Abstract

ABSTRACT The Government of Iran estimates the country’s initial-oil-in-place and condensate-in-place are about 600 and 32 billion barrels (Gb), respectively. In 2004, the official estimate of the proved remaining recoverable oil and condensate reserves was about 132.5 Gb, of which crude oil accounted for about 108 Gb. Cumulative crude oil production is expected to cross the 60 Gb mark in 2007, implying that the estimated ultimate recoverable reserves of crude oil are about 168 Gb (cumulative production plus remaining reserves) and the total recovery factor is about 28%. The main Oligocene-Miocene Asmari and Cretaceous Bangestan (Ilam and Sarvak) reservoirs contain about 43% and 25%, respectively, of the total crude oil-in-place. Recovery factors for the Asmari range between about 10–60%, and for the Bangestan between 20–30%. Between 1974 and 2004 remaining recoverable reserves have increased from about 66 to 108 Gb, while the ultimate recoverable reserves have increased from 86 to 168 Gb. In contrast to 1974 when Iran’s production peaked at 6.0 Mb/d, production in 2005 averaged about 4.1 Mb/d. The 1974 peak occurred when production from most of the giant fields was ramped-up to very high but unsustainable levels. Current plans are to increase the crude oil production rate to 4.6 Mb/d by 2009. This is a significant challenge because this production capacity has to offset a reported total annual decline rate of 300–500,000 barrels/day (Kb/d). This high decline rate is attributed to the maturity of the giant fields, many of which attained their peaks in the 1970s and have produced about half or more of their estimated ultimate recoverable reserves. Therefore to achieve the 2009 production target within the next three years, Iran has to add about 680 Kb/d of capacity per year from its developed fields (infill drilling, recompletions, enhanced and improved oil recovery), while also adding net new surface facilities and well capacity from undeveloped fields and reservoirs.