Interpreting Reserves - Moving from Reserves to URR

Interpreting reserves: moving from reserves to URR. Given the conservative nature of reserve estimates, the resulting reserve growth over time, and other associated issues, the ultimately recoverable resource (URR) is a more useful resource classification when assessing future petroleum resource availability. This abstract describes some of the findings of a systematic review of the evidence surrounding resource and reserve estimates for both conventional oil and unconventional gas. This review includes discussion of the methodological approaches that can be used, the difficulties associated with these methodologies and the particular issues associated with estimating unconventional resources. It finds that the most robust estimates are likely to arise from a combination of methodological approaches.