关键词: 天然气储层, 随机建模, 物性参数, 概率储量

Abstract: The uncertainties of a gas reservoir located in the north part of Shaanxi Province were studied with stochastic modeling. The responding gas reserves of the reservoir were calculated with three groups of data obtained from two hundreds and fifty four wells, one hundred and forty six wells, thirty wells by using fifty, one hundred and two hundreds of random seeds, respectively. Probabilistic distributions of these reserves were analyzed. Three probabilistic reserves (P90, P50, P10) for the three groups of data were obtained respectively by using one hundred of random seeds. The probabilities of three probabilistic reserves larger than the real reserves are 90 percent, 50 percent and 10 percent respectively. The calculated results illustrate that as the number of wells increase, the mean values of gas reserves continuously increase, and their mean variances decrease, which results in the reduction of the uncertainties of reservoir. The top strata surface and net thickness were obtained by Kriging method. The spatial distributions of porosity, permeability and gas saturation were obtained by simulation of Gaussian field.

Key words: natural gas reservoir, stochastic modeling, physical parameter, probabilistic reserves