碳酸盐岩储集层微裂缝的识别与表征

采用基于孔隙几何形状与结构的岩石分类方法，利用碳酸盐岩储集层A和碳酸盐岩储集层B岩石样品的常规岩心、特殊岩心分析数据和薄片照片，对岩石样品进行分类，识别并表征碳酸盐岩储集层岩石样品中的微裂缝。碳酸盐岩储集层A的各类岩石中均发育微裂缝；而碳酸盐岩储集层B中，只有孔隙度为1%～11%、孔洞较少、硬度为中硬—硬的部分类型岩石样品中发育微裂缝。建立确定各类岩石截止孔隙度的方法，以区分发育导流型微裂缝与不发育导流型微裂缝的岩石样品，分析导流型微裂缝在提高渗透率方面的作用。基于渗透率和初始含水饱和度的关系，结合基于孔隙几何形状与结构的岩石分类方程，筛选出发育导流型微裂缝的特殊岩心分析数据建立渗透率预测方程，成功预测了含有导流型微裂缝的岩石样品的渗透率。

Identification and characterization of microfractures in carbonate samples

Based on the rock typing method of pore geometry and structure(PGS),rock samples from carbonate reservoir A and carbonate reservoir B were classified using data of routine and special core analysis and thin section images,and microfractures in the carbonate reservoir samples were identified and characterized.Establishment of rock types demonstrates that microfractures have developed in all rock types in carbonate reservoir A,but only partially in certain rock types in carbonate reservoir B with porosity of 1%–11%,less vuggy,and hardness of medium hard to hard.The cut-off porosity was determined for each type of rock to distinguish samples with and without conductive microfractures.The impact of conductive microfractures on improving permeability was analyzed.On the basis of relationship of permeability and original water saturation,the permeability equation was derived by certain special core analysis data with conductive microfractures selected by PGS equation,and the permeability of samples with conductive microfractures has been successfully predicted.