利用分形模拟建立裂缝型碳酸盐岩储层渗透率变异函数

裂缝型碳酸盐岩储层的各级裂缝为渗透率的主要贡献者，储层裂缝分布规律通常难以把握，建立裂缝型碳酸盐岩储层的渗透率变异函数具有相当大难度。然而，裂缝型碳酸盐岩储层的裂缝分布符合分形规律，为此以塔里木盆地轮南古潜山裂缝型碳酸盐岩储层为例，定量分析碳酸盐岩储层裂缝分布的分形规律，提出碳酸盐岩储层裂缝分布的分维数和分形预测公式，与由地应力导出的平面渗透率趋势场数据统计相结合，由分形预测决定的标准化变异函数曲线来确定渗透率变异函数的曲线形态，由地应力导出的平面渗透率趋势数据统计得到渗透率变异函数的变程与拱高，使渗透率与裂缝分布的相关关系相符合，构建起反映裂缝型碳酸盐岩储层渗透率空间相关性的变异函数。实践证明，由该变异函数导出的储层渗透率参数模型较好地反映了储层渗透率实际分布。

APPLICATION OF FRACTAL SIMULATION TECHNIQUE TO MODELING OF FRACTURED CARBONATE RESERVOIR

Various scaled fractures developed in carbonate reservoirs are the main contributors of permeability. In general, it is difficult to figure out distribution rules of such fractures, putting considerable difficulty on setting up permeability variation functions for fractured carbonate reservoirs. However, it was found that the fracture distribution in such reservoirs observed the fractal geometry. Therefore, the fractured carbonate reservoir of Lunnan ancient buried hill in the Tarim Basin was taken as an example to analyze the fractal geometry of fracture distribution quantitatively and derive the dimensional and fractal prediction formula. With the statistics of 2D permeability distribution derived by earth stress to control the variation and camber, the curve type of the standard variation function is decided by the fractal prediction. In this way, the calculated permeability matches the fracture distribution very well. And the resulted variation function appropriately represents the spatial relevance between fracture distribution and reservoir permeability.