More about Discovery Process Models
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log pool size, and all the pools beyond the fi rst break on the right-hand
side of the plot had already been discovered. Therefore, the average
ratio or a single ratio obtained from discovered pools can be applied to
estimate the number of small-size pools. These two methods are ad hoc
procedures. Furthermore, a J-shaped sample distribution is not indicative of a Pareto population (Lee, 1993b).
Estimation Error Resulting from Lognormal Distribution Approximation
If we apply a lognormal assumption to the Weibull, gamma, and Pareto
distributions, the errors resulting from an incorrect statistical assumption decrease as the sample size increases (see tables 4.1 through 4.4).
The lognormal family (including the power normal) is not perfect,
but has proved to be the best among the four distributions tested. It
can, at least, describe the economically viable portion of the play and
yield estimates for ongoing exploration planning.