Evolution of Oil Assessments
by C.J.Campbell


Assessing the world's endowment of oil would not be a particularly difficult task were it not for the atrociously unreliable database on what has been found so far. The analyst has therefore to spend much time and effort defining the data and removing the worst anomalies before addressing the nature of depletion. Critics relish pointing out how the assessment has evolved over time, taking it as evidence that depletion studies are meaningless. A good response would be to quote the famous economist, Maynard Keynes, who on being accused of inconsistency replied. "When I have new information, I change my conclusions. What do you do? Sir."

The following table plots the essential statistics of successive assessments of conventional oil

They are not however strictly comparable because:

The early estimates were based on public domain data, before the degree of misreporting by industry and governments was appreciated.

It has been stressed that all numbers, which are quoted as computed, are to be generously rounded. No one should imagine that this is an exact science.

CONVENTIONAL OIL 1989 1990 1992 1993 1995 1996 1996 1997 1997 1997 1998 1998 1999
References #1 #2 #3 #4 #5 #6 #7 #8 #9 #9 #10 #11 #12
Produced (billion barrels) 600 628 697 718 761 784 800 807 785 784 815 817 820
Reserves (") 725 806 725 722 800 836 850 830 823 836 810 821 827
Discovered (") 1325 1434 1422 1440 1561 1620 1650 1637 1618 1620 1625 1638 1647
Yet-to-Find (") 250 216 228 210 189 180 150 165 182 180 175 162 153
Yet-to-Produce (") 975 1022 953 932 989 1016 1000 995 1005 1016 985 983 980
Ultimate (") 1575 1650 1650 1650 1750 1800 1800 1800 1800 1800 1800 1800 1800
Depletion Rate (annual) 2.3% 2.1% 2.3% 2.3% 2.6% 2.6%     2.6% 2.6%     2.2%
Depletion Midpoint (year)   1998 1998 1998 2000 2001     2001 2001     2003

Produced + Reserves = Discovered
Reserves + Yet-to-Find = Yet-to-Produce
Produced + Yet-to-Produce = Ultimate
Click here to see a plot of all variables

References
#1 Noroil, v.17/12 Dec 1989
#2 Golden Century of Oil
#3 Petrole et Technique, Oct 1993
#4 Energy Exploration & Exploitation, 13/1. 1995
#5 Oxford Energy Forum, v28 1997
#6 Oil & Gas Journal, April 7th 1997
#7 Scientific American v 278/3. 1998
#8 The National Interest, Spring 1998
#9 World's Non-conventional Oil & Gas, Pet. Economist
#10 Petroleum Expl. Soc. of Gt. Britain
#11 Geopolics of Energy, Jan. 1999
#12 Tomorrow's Oil, v 2/2 Feb.2000

Last Updated on 3/23/2000