基于高分辨率CT的孔隙型白云岩储层孔隙系统分形与多重分形研究  

Fractal and Multifractal Research on Pore System for Porous Dolomite Reservoirs Based on High-Resolution CT

作　　者：张天付[1,2,3] 谢淑云[1] 鲍征宇[1] 王莹[2,3] 潘丽银 

机构地区：[1]中国地质大学(武汉)地球科学学院,武汉430074 [2]杭州地质研究院,杭州310023 [3]中国石油天然气集团公司碳酸盐岩储层重点实验室,杭州310023

出　　处：《地质科技情报》2016年第6期55-62,共8页Geological Science and Technology Information

基　　金：中国石油股份有限公司重大专项"冀中坳陷奥陶系储层发育特征及其非均质性研究"(21403(16))

摘　　要：孔隙型白云岩储层由于孔隙类型的多样性、孔隙结构的复杂性和非均质性,需要运用新手段对其孔隙系统进行刻画和表征。综合利用高分辨率微纳米CT技术和分形与多重分形理论,通过不同孔隙类型、不同样品尺度的CT图像二维系列切片和三维数字岩心数据体研究,讨论了粒间孔、晶间孔、铸模孔等不同孔隙系统的分形与多重分形特征。结果表明,晶间孔、粒间孔、铸模孔和混合孔等孔隙在分形盒子维数上有明确的响应,二维系列切片盒子维数值的相对大小为:铸模孔>粒间孔>晶间孔>混合孔。盒子维数与孔隙度、渗透率的数据对比表明,孔隙度可能也对盒子维数产生影响。通过对粒间孔和铸模孔样品孔隙系统在三维空间上的多重分形分析,揭示其孔隙结构标度-频率图是一条直线,为典型的幂律分布,即在不同尺度上具有标度不变性;在多重分形频谱图上是连续频谱分布,为明显的多重分形分布特征,反映了三维空间上孔隙分布的不均一性。Pore system of porous dolomite reservoirs need to be studied by the new method due to its diversity of type, complexity and heterogeneity of pore structure. In order to research the impact of pore types and size on fractal and multifractal for porous dolomite reservoirs, this paper uses high-resolution CT technique to show the characteristics of fractal and multifractal for intergranular pore, intercrystalline pore, moldic pore and mixed pore in porous dolomite. The results indicate Dbox, regularity index of pore shapes, has different responses for different pore systems. The order of Duox for different types of pores, sorted by value, was moldic, intergranular, intercrystalline and mixed. Additionally, porosity could influence Dbo., according to porosity and permeability analyzing. Furthermore, the multifraetal research on pore structure in 3D for intergranular pore and moldic pore had shown linear relationship between scale and frequency in multifractal spectrum curves, such as partition function of the pore space pixels and the cube-counting size, corresponding to power law distribution. That was to say, it was scale invariance for different scales. Typical continuous spectrum distribution in multifractal spectrum curves is the obvious character of multifractal, reflecting the heterogeneity.

关 键 词：孔隙型白云岩 孔隙系统 非均质性 分形维数 多重分形谱函数 

分 类 号：P618.130.21[天文地球—矿床学]