相控下的天然气概率储量计算研究

对沉积微相空间分布的控制条件下天然气概率储量的计算方法进行了研究。对14口井的资料应用储层随机建模方法，研究了陕北某气田的一个天然气储层。首先确定沉积微相如潮间含膏云坪、潮间潮缘泻、潮下泥云坪、潮下泥灰坪湖、潮上膏云坪等的空间分布，并以此控制，求取了孔隙度、渗透率、含气饱和度等物性参数的空间分布，进而计算储量。利用50个随机种子，计算了有沉积微相控制的概率储量和没有沉积微相控制的概率储量，并进行了对比分析。有沉积微相控制的概率储量明显地大于没有沉积微相控制的概率储量相应的天然气储量，说明了考虑沉积微相的控制作用的必要性。

STUDY ON THE CALCULATION OF PROBABILISTIC RESERVES UNDER THE CONTROL CONDITIONS OF SEDIMENTARY MICROFACIES SPATIAL DISTRIBUTION

The method of calculating gas probabilistic reserves is studied under the control conditions of sedimentary microfacies spatial distribution. The gas reservoir in north Shaanxi is approached by reservoir stochastic modeling and with the data from 144 wells. On the basis of determining the spatial distributions of sedimentary microfacies: i.e. gypseous dolomite ground of tideland, tide-edge lagoon facies,mudly dolomite ground of undertide, gypseous dolomite ground of undertide and gypseous dolomite ground of overtide, and taking these as control, the spatial distributions of petrophysical parameters, such as porosity, permeability and gas saturation are obtained, and then the reserves are calculated. With 50 random seeds, probabilistic reserves under control of spatial distribution of sedimentary facies, and without the control, are calculated and analyzed. The former probabilistic reserves obviously are bigger than the latter ones. This illuminates the consideration of facies-control to probabilistic reserves is very necessary.