低渗透储集层T_2截止值实验研究

Experimental Study of T_2 -cutoff values in low-permeability reservoirs

由于一个地区甚至一口井很难有一个统一的截止值,无法用单一的截止值方法区分束缚水和自由流体,因而核磁共振测井解释束缚水饱和度存在着实用上的困难.为此,本文借鉴已发表的实验方法对塔中地区低渗透储层岩心进行核磁共振实验.实验结果分析时充分考虑岩石孔隙结构的变化,发现T2截止值与孔隙结构综合指数(k)密切相关,提出了一种应用于测井解释的变T2截止值方法,并在实际测井解释中获得了良好的应用效果.

There isn't a unification cutoff value in some one region/well, so it isn't to distinguish the irreducible water and free fluid using single cutoff value, and then the irreducible water saturation is difficult to be interpreted by NMR logging in oilfield. Therefore, the experiments of core NMR of the low-permeability reservoir in Tazhong oilfield are done adopting the published experimental method in the paper. Considering the variety of the rock pore structure, it shows that the relationship between the cutoff value of the transverse relaxation time(T_(2)) and the synthesized index(k) of the pore structure is very well by using the experimental results. And it is proposed that the method of the varying T_(2)-cutoff value is applied to the log interpretation. It makes known that the proposed method is well available to the practical log interpretation.