远景评价的目的就是在钻井以前对要勘探的远景构造的可采烃量进行估计。这种远景评价与钻井以后估算储量不同,就是要考虑到某些不确定性。因此,在估算中的所有参数用概率分布表示而不是用单个数宇时,才可能做到这点。用概率方法的常规做法是进行重复计算, The purpose of the long-term evaluation is to estimate the amount of recoverable hydrocarbon for the long-term prospect to be explored prior to drilling. This kind of long-term evaluation differs from the estimated reserves after drilling to take into account some uncertainties. Therefore, it is possible to do this when all the parameters in the estimate are represented by a probability distribution instead of a single number. The usual way of using probabilistic methods is to do double counting,