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分形体系是具有标度不变性的自相似结构，可定义为酋从幂律分布客体的标度不变集。应用分形分面概念和方法，对四川盆地各层系的气藏分层统计研究的结果表明，在一定区域各层系内气藏的体积分布很好地酋从幂律分布规律，是一种分形分布，其分维值介于０．１４－０．６１之间，分维可作为客体间相对重要性的度量值。通过对气藏与油藏体积分布分维值差异的比较和对四川盆地不同层系气藏体积分布分维特征的研究后认为，分维还反映了裂不

STATISTICAL STUDY OF DISTRIBUTIONS OF SIZE-DIFFERENT GAS RESERVOIRS AT STRATA IN SICHUAN BASIN

??Fractal system are self-similaritical structures possessing scale invariance and can be defined as scale invariant sets that obey power-law distribution.By applying the concepts and methods of fractal distribution to the statistical study of gas reservoirs at strata in Sichuan Basin,the results show that distribution of size-different gas reservoirs at strata obey power-law distributions quite well within a defined area and are fractal distributions.Their fractal dimensions are in the range of 0.14??0.61.Fractal dimension is a measure of relative importance of gas reservoirs.In addition,through the comparison of fractal dimension difference of the distributions between gas reservoirs and petroleum reservoirs,and the characteristics of fractal dimension at strata in Sichuan Basin,we find that the fractal dimension still reflect the connectedness of fractures,the better connection,the smaller the fractal dimension,and the fractal dimensions of size distribution of gas reservoirs are smaller than that of the petroleum ones.Morever,by exploring the significance of fractal distribution,a method of preliminarily forcasting the number and the reserves of reservoirs is proposed out,and the exploration prospects of various strata are analysed.