ANALYSIS OF RESERVES DISCOVERED IN PETROLEUM EXPLORATION

Mathematical theory and empirical data show that discovery sizes from mature plays have lognormal distributions. This allows a simple transformation to be used that converts lognormal trends to straight lines from which valuable statistical data on exploration potential is derived.
After correcting for the unreliable nature of data from non-commercial accumulations and then discounting the extreme high ends and low ends (P1), discovery size distributions from a variety of mature plays outside the Middle East show certain common properties that help constrain reserves ranges in individual prospects and new play fairways. These are:

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  P99 is 0.3MM brl or less in non-DHI oil plays and 4BCF or less in gas plays at normal depths;