Gas resources assessment methods could be divided into two kinds: genetic method and statistical simutation method. The assessment results of these two methods obtained from the same geologic unit may differ differently

and usually the result of the genetic method is greater than that of the later. But combine these two methods together

use Pareto truncated distribution as numerical model

use iterative algorithm to obtain uniform results

the size

the number and the distribution of the gas fields and also gas resources enrichment which in a very important parameter for regional estimation analysis.