Further in talking with Baker Hughes folk (the ones that track the wells that are drilled around the world), he found that those who thought depletion in old fields was less than 5% got no takers from his audience, 60% of the audience thought that depletion was between 6 and 8% and the remainder thought that it was in the range above 10%. (As noted earlier the assumed value is often taken as somewhere between 2 & 4% with TOD using around 4.5%). It was by far the most pessimistic that I have heard him give.

Why does TOD use a decline rate of 4.5%, which is the same rate assumed by CERA?

Schlumberger has estimated an 8% (and growing) world oil production decline rate. TOD and CERA's 4.5% rate seems too optimistic and not very realistic.

Robert Hirsch writes:

Schlumberger may have better data than anyone else on oil fields throughout the world, because they operate almost everywhere that oil is produced. This includes the OPEC countries, where most data are considered state secrets. For IHS or CERA to have better data, they would have to have a competent, far-reaching spy network, which IHS/CERA has not claimed and couldn’t claim without significant repercussions. Indeed there is no indication that IHS/CERA has better oil field data than anyone else. Schlumberger and Gould have been too responsible for too long to believe that they would off-handedly estimate an 8% decline rate without knowing the facts. An 8% world oil production decline rate means that the world is in for very serious oil shortages almost any time now.

[Note: The frightening thing is that the Hirsch report only assumed a two percent decline rate.]