基于分形特征的碳酸盐岩储层孔隙结构定量评价  

Quantitative evaluation of carbonate reservoir pore structure based on fractal characteristics

作　　者：刘航宇 田中元[1] 徐振永[1] LIU Hangyu;TIAN Zhongyuan;XU Zhenyong(Petrochina Research Institute of Petroleum Exploration and Development,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083

出　　处：《岩性油气藏》2017年第5期97-105,共9页Lithologic Reservoirs

基　　金：国家"十三五"重大科技专项"伊拉克大型生物碎屑灰岩油藏注水开发关键技术研究与应用"(编号:2017ZX05030-001)资助

摘　　要：伊拉克W油田Mishrif组巨厚孔隙型生屑灰岩为强非均质性储层,孔隙结构评价难度较大。结合薄片、孔渗试验和压汞毛管压力曲线资料,使用分形理论研究储层孔隙结构,建立了以分形维数定量评价孔隙型生屑灰岩储层孔隙结构的方法和标准。该储层孔隙结构分形特征可分为2类,第1类储层孔隙结构整体具有显著的"单段型"分形特征;第2类储层孔隙结构整体分形特征不显著,但其较大孔喉系统和较小孔喉系统各自具有显著的分形特征,即"多段型"分形特征。分形维数能够反映孔隙型灰岩孔隙结构的复杂程度和非均质性,分形维数越大,孔隙结构越复杂;压汞毛管压力和含水饱和度分段越多,孔隙结构非均质性越强。利用孔隙结构分形维数的分区性对储层进行分类,同一类样品压汞毛管压力曲线的相似性验证了分形维数分类结果的合理性。Ⅰ类与Ⅱ类储层多对应"多段型"分形特征,Ⅲ类与Ⅳ类储层多对应"单段型"分形特征。该研究成果对相同类型碳酸盐岩储层孔隙结构定量评价具有指导意义。Pore structure of large scale porous limestone reservoir with strong heterogeneity is very complex,so it is difficult to evaluate its pore structure of Mishrif Formation of W oilfield in Iraq.Based on thin section observation,porosity and permeability test and mercury injection capillary pressure test,fractal theory was applied to quantitative pore structure evaluation,and the pore fractal dimension criterion for reservoir type classification was established.There are two types of reservoir pore structure fractal characteristics.Some samples called“single segment”perform obvious fractal character overall.Others called“multiple segments”have distinct large pore throat system and small pore throat system which perform unique fractal characters respectively while have no uniform fractal character overall.The complexity and heterogeneity of pore structure of porous limestone can be reflected by fractal dimension,the greater the fractal dimension,the more complex pore structure,and the more conspicuous segmental character in the relationship between capillary pressure and water saturation,the stronger the heterogeneity.The samples were classified based on the fractal dimension combined with porosity and permeability distribution of the samples.The majority of typeⅠ-Ⅱand typeⅢ-Ⅳrespectively corresponded to“multiple segments”and“single segment”fractal characteristics.It has an important guiding significance for the quantitative evaluation of pore structure to similar carbonate reservoir.

关 键 词：孔隙型灰岩 孔隙结构 分形特征 压汞毛管压力 储层分类 

分 类 号：TE122[石油与天然气工程—油气勘探]