In this paper, we use results from the Hotelling model of non-renewable resources to examine the mainstream view among economists that improvements in recovery technology can offset declines in petroleum reserves. We present empirical evidence from two well-documented mega-oilfields: the Forties in the North Sea and the Yates in West Texas. Patterns of depletion in these two fields suggest that technology temporarily increases the rates of production at the expense of more pronounced rates of depletion in later years-in line with Hotelling's predictions. Insofar as our results are generalizable, they call into question the view of most economists that technology can mitigate absolute resource scarcity. This raises concerns about the capacity of current mega-fields to meet future oil demand. (c) 2006 Elsevier Ltd. All rights reserved.