孔隙岩样动电特性的实验研究  

Experimental study on electrokinetic properties of porous rock samples

作　　者：王军[1] 胡恒山[1] 关威[1] 尹诚刚[1] 

机构地区：[1]哈尔滨工业大学航天学院,哈尔滨150001

出　　处：《地球物理学报》2016年第9期3514-3523,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41674121;41304091;11372091;41204092);黑龙江省留学归国科学基金(LC201420);国家54批博士后基金(2013M541357);中央高校基本科研业务费专项资金(HIT.NSRIF.2014028)资助

摘　　要：本文针对流体饱和孔隙介质的动电效应,在实验室内进行了小岩样的动电实验(流动电势实验)测量,获得了10块岩样在6种不同饱和浓度下的流动电势系数,进而分析了饱和溶液浓度、岩样渗透率和泥质含量对流动电势系数的影响,探讨了流动电势系数对上述参数的敏感性,并进一步给出了流动电势系数随这些参数的变化规律.实验结果表明:前人流动电势系数频响曲线中的凹点现象是由实验装置的共振引起,并非岩样动电效应的自身特性.实验还发现:孔隙介质的动电耦合能力与溶液浓度有关,流动电势系数随溶液浓度增大而减小,但在很高浓度溶液中,动电现象依然存在,流动电势系数趋于常数.此外,流动电势系数对地层参数(渗透率和泥质含量)的敏感性受溶液浓度影响较大,随着溶液浓度增大,敏感性降低.因此,可在低浓度饱和情况下(低于0.4mol/L),利用流动电势系数的幅度对地层渗透率进行直接评价.本文结果对动电测井的可行性及应用条件给出了实验说明.This paper presents the streaming potential experiments conducted in the laboratory with saturated porous rocks in the low frequency domain.The streaming potentials and streaming currents of ten rock samples are recorded by a lock in amplifier.Then the streaming potential coefficients are calculated and analyzed at six different saturation concentrations.The influences of solution concentration,rock permeability and clay content on streaming potential coefficient are studied in order to reveal the relationship between the coefficient and these parameters.The experimental results show that the streaming potential coefficient decreases with increasing solution concentration,while the electrokinetic phenomenon still exists even in solution with relatively high concentration.The results also show that the concave that appeared in the frequency response of streaming potential coefficient is not caused by the electrokinetic property,but the resonance of core-holder.In addition,this work demonstrates that the amplitude of streaming potential coefficient can be directly used to evaluate permeability in the lower concentration that is less than 0.4mol/L.This study verifies the feasibility of electrokinetic well logging and indicates its application conditions for the experimental measurements.

关 键 词：动电效应 动电测井 流动电势 渗透率 

分 类 号：P631[天文地球—地质矿产勘探]