Abstract: The discovery process model in Chapters 4 and 7 of Lee’s Statistical Methods for Estimating Petroleum Resources is the important theoretical foundation to evaluate oil and gas resources. Lee uses probability density functions of Lognormal distribution, Weibull distribution, Gamma distribution, Logistic distribution and Pareto distribution to describe the discovery process of unimodal cyclic resources in a petroliferous basin. But, it is found that except for Lognormal distribution, other 4 distributions are all wrong, which will inevitably influence the accuracy of the model. Additionally, dimension transformation must be performed to establish a reliable prediction model because the probability density function is a dimensionless quantity of 0~1. But Lee never mentions the dimension transformation of the probability density functions in his monograph. Based on comparison, the authors point out the mistakes of probability density functions introduced by Lee, and establishes a prediction model to evaluate petroleum resources through dimension transformation and derivation