低频交变压差作用下岩心流动电流和zeta电势实验测量
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摘要
实验测量岩样zeta电势,对于认识地震诱导的电磁场现象以及探索利用动电效应的测井方法具有重要意义.本文介绍了专门设计的岩样流动电流和流动电势实验测量系统及一种获得岩样zeta电势的测量方法——流动电势和流动电流综合测量法.实验采用交流锁相放大技术,测量了3～100 Hz频率范围内交变压差作用下岩样的流动电势系数和流动电流系数,实验表明,这两个系数均随溶液浓度增大而减小,随pH值增大而增大.实验通过对不同浓度饱和岩样的流动电势和流动电流测量,获得了岩样的有效面积-长度比,进而计算出岩样的zeta电势和表面电导.实验还论证了忽略表面电导是导致常规流动电势测量法获得zeta电势低于实际值的原因.
The experimental measurements on zeta potential are important for the study of the electrokinetic phenomena during an earthquake and of the electrokinetic well logging methods. An experimental test system is devised to measure the rock streaming potential and streaming current.By employing the AC lock-in technique,the streaming potential coefficient and streaming current coefficient are experimentally obtained at the low frequency range between 3 and 100 Hz. The experimental results show that both coefficients decrease as the ion concentration increases, and grow as the solution pH value increases.By combining the streaming potential and streaming current measurements at different concentrations,the effective surface-to-length ratio of a core sample is obtained,which is used to calculate the zeta-potential and the surface conduction. The results also demonstrate that the neglect of surface conduction as in the conventional streaming potential method leads to underestimation of the zeta potential at the low concentrations.
The experimental measurements on zeta potential are important for the study of the electrokinetic phenomena during an earthquake and of the electrokinetic well logging methods. An experimental test system is devised to measure the rock streaming potential and streaming current.By employing the AC lock-in technique,the streaming potential coefficient and streaming current coefficient are experimentally obtained at the low frequency range between 3 and 100 Hz. The experimental results show that both coefficients decrease as the ion concentration increases, and grow as the solution pH value increases.By combining the streaming potential and streaming current measurements at different concentrations,the effective surface-to-length ratio of a core sample is obtained,which is used to calculate the zeta-potential and the surface conduction. The results also demonstrate that the neglect of surface conduction as in the conventional streaming potential method leads to underestimation of the zeta potential at the low concentrations.
引文
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[2] Ishido T,Mizutani H.Experimental and theoretical basis of electrokinetic phenomena in rock-water systems and its application to geophysics.J.Geophy.Res.,1981,86(B3) :1763-1775
[3] Thompson A H,Gist G A.Geophysical application of electrokinetic conversion.The Leading Edge,1993,12(12) :1169
[4] Fenoglio M A,Johnston M J S,Byerlee J D.Magnetic and electric fields associated with changes in high pore pressure in fault zones;Application to the Loma Prieta ULF emissions.J.Geophys.Res.,1995,100(B7) :12951-12958
[5] Zlotnicki J,LeMouel J L.Possible electrokinetic origin of large magnetic variations at La fournaise volcano.Nature,1990,343(6259) :633-635
[6] Revil A,Pezard P A.Streaming electrical potential anomaly along faults in geothermal areas.Geophys.Res.Lett.,1998,25(16) :3197-3200
[7] Wurmstich B,Morgan F D.Modeling of streaming potential responses caused by oil well pumping.Geophysics,1994,59(1) :46-56
[8] Pride S R.Governing equations for the coupled electromagnetics and acoustics of porous media.Phys Rev.B.,1994,50(21) :15678-15696
[9] Bastos D,de las Nieves F J.On the zeta-potential of sulfonated polystyrene model colloids.Progr.Colloid Polym.Sci.,1993,93:37-44
[10] Dukhin S S,Zimmermann R,Werner C.Electrokinetic phenomena at grafted polyelectrolyte layers.J.Colloid Interface Sci.,2005,286(2) :761-773
[11] Haartsen M W,Pride S R.Electroseismic waves from point sources in layered media.J.Geophys.Res.,1997,102(B11) ;24745-24769
[12] Guan W,Hu H S.Finite-difference modeling of the electroseismic logging in a fluid-saturated porous formation.Journal of Computational Physics,2008,227(11) :5633-5648
[13] Guan W,Hu H S,Chu Z T.Formulation of the acoustically-induced electromagnetic field in a porous formation in terms of Hertz vectors and simulation of the borehole electromagnetic field excited by an acoustic multipole source.Acta Physica Sinica(in Chinese),2006,55(1) :267-274
[14] Gao Y X,Hu H S.Seismoelectromagnetic waves radiated by a double couple source in a saturated porous medium.Geophysical Journal International,2010,181(3) :873-896
[15] Repport P M,Morgan F D.Streaming potential collection and date processing techniques./.Colloid Interface Sci.,2001,233(2) :348-355
[16] Li S X,Pengra D B,Wong P Z.Onsager's reciprocal relation and the hydraulic permeability of porous media.Phys.Rev.E.,1995,51(6) :5748-5751
[17] Reppert P M,Morgan F D,Lesmes D P,et al.Frequency-dependent streaming potentials.J.Colloid Interface Sci.,2001,234(1) :194～203
[18] 王军,胡恒山 孙宝佃等.基于动电效应的岩芯渗透率实验测量.地球物理学报,2010,53(8) :1953～1960
Wang J,Hu H S,Sun B D,et al.Experimental measurement study on rock permeability based on the electrokinetic effect.Chinese J.Geophys.(in Chinese),2010,53(8) :1953-1960
[19] Alkafeef S F,Gochin R J,Smith A L.Measurement of the electrokinetic potential at reservoir rock surfaces avoiding the effect of surface conductivity./.Colloid and Surfaces.A:Physicochem.Eng.Aspects,1999,159(2-3) :263-270
[20] Schweiss R,Welzel P B,Werner C,et al.Interfacial charge of organic thin films characterized by streaming potential and streaming current measurements.J.Colloid and Surfaces.A:Physicochem.Eng.Aspects,2001,195(1-3) :97～102
[21] Pengra D B,Li S X,Wong P Z.Determination of rock properties by low-frequency AC electrokinetics.J.Geo.Res.,1999,104(B12) .29485-29508
[22] 高晋占.微弱信号检测.北京:清华大学出版社,2004
Gao J Z.Detection of Weak Signals(in Chinese).Beijing:Tsinghua University Press,2004
[23] Korpi G K,de Bruyn P L.Measurement of streaming potentials.J.Colloid Interface Sci.,1972,40(2) :263-266
[24] FinnoRJ,Chung K,Yin J,et al.Coefficient of permeability from AC electroosmosis experiments.Ⅱ:Results.J.Geophys.Engrg.,1996,122(5) :355-364
[25] Pride S R,Morgan F D.Electrokinetic dissipation induced by seismic waves.Geophysics,1991,56(7) :914-925
[26] 高永新,胡恒山.水平分层孔隙介质中点源激发的震电波场数值模拟及分析.地球物理学报,2009,52(8) :2093～2104
Gao Y X,Hu H S.Numerical simulation and analysis of seismoelectromagnetic wave fields excited by a point source in layered porous media.Chinese J.Geophys.(in Chinese),2009,52(8) :2093～2104
[27] 胡恒山,刘家琦,王洪滨等.基于简化的Pride理论模拟声电效应测井响应.地球物理学报,2003,46(2) :259～264
Hu H S,Liu J Q,Wang H B,et al.Simulation of acousto-electric well logging based on simplified pride equations.Chinese J.Geophys.(in Chinese),2003,46(2) :259-264
[2] Ishido T,Mizutani H.Experimental and theoretical basis of electrokinetic phenomena in rock-water systems and its application to geophysics.J.Geophy.Res.,1981,86(B3) :1763-1775
[3] Thompson A H,Gist G A.Geophysical application of electrokinetic conversion.The Leading Edge,1993,12(12) :1169
[4] Fenoglio M A,Johnston M J S,Byerlee J D.Magnetic and electric fields associated with changes in high pore pressure in fault zones;Application to the Loma Prieta ULF emissions.J.Geophys.Res.,1995,100(B7) :12951-12958
[5] Zlotnicki J,LeMouel J L.Possible electrokinetic origin of large magnetic variations at La fournaise volcano.Nature,1990,343(6259) :633-635
[6] Revil A,Pezard P A.Streaming electrical potential anomaly along faults in geothermal areas.Geophys.Res.Lett.,1998,25(16) :3197-3200
[7] Wurmstich B,Morgan F D.Modeling of streaming potential responses caused by oil well pumping.Geophysics,1994,59(1) :46-56
[8] Pride S R.Governing equations for the coupled electromagnetics and acoustics of porous media.Phys Rev.B.,1994,50(21) :15678-15696
[9] Bastos D,de las Nieves F J.On the zeta-potential of sulfonated polystyrene model colloids.Progr.Colloid Polym.Sci.,1993,93:37-44
[10] Dukhin S S,Zimmermann R,Werner C.Electrokinetic phenomena at grafted polyelectrolyte layers.J.Colloid Interface Sci.,2005,286(2) :761-773
[11] Haartsen M W,Pride S R.Electroseismic waves from point sources in layered media.J.Geophys.Res.,1997,102(B11) ;24745-24769
[12] Guan W,Hu H S.Finite-difference modeling of the electroseismic logging in a fluid-saturated porous formation.Journal of Computational Physics,2008,227(11) :5633-5648
[13] Guan W,Hu H S,Chu Z T.Formulation of the acoustically-induced electromagnetic field in a porous formation in terms of Hertz vectors and simulation of the borehole electromagnetic field excited by an acoustic multipole source.Acta Physica Sinica(in Chinese),2006,55(1) :267-274
[14] Gao Y X,Hu H S.Seismoelectromagnetic waves radiated by a double couple source in a saturated porous medium.Geophysical Journal International,2010,181(3) :873-896
[15] Repport P M,Morgan F D.Streaming potential collection and date processing techniques./.Colloid Interface Sci.,2001,233(2) :348-355
[16] Li S X,Pengra D B,Wong P Z.Onsager's reciprocal relation and the hydraulic permeability of porous media.Phys.Rev.E.,1995,51(6) :5748-5751
[17] Reppert P M,Morgan F D,Lesmes D P,et al.Frequency-dependent streaming potentials.J.Colloid Interface Sci.,2001,234(1) :194～203
[18] 王军,胡恒山 孙宝佃等.基于动电效应的岩芯渗透率实验测量.地球物理学报,2010,53(8) :1953～1960
Wang J,Hu H S,Sun B D,et al.Experimental measurement study on rock permeability based on the electrokinetic effect.Chinese J.Geophys.(in Chinese),2010,53(8) :1953-1960
[19] Alkafeef S F,Gochin R J,Smith A L.Measurement of the electrokinetic potential at reservoir rock surfaces avoiding the effect of surface conductivity./.Colloid and Surfaces.A:Physicochem.Eng.Aspects,1999,159(2-3) :263-270
[20] Schweiss R,Welzel P B,Werner C,et al.Interfacial charge of organic thin films characterized by streaming potential and streaming current measurements.J.Colloid and Surfaces.A:Physicochem.Eng.Aspects,2001,195(1-3) :97～102
[21] Pengra D B,Li S X,Wong P Z.Determination of rock properties by low-frequency AC electrokinetics.J.Geo.Res.,1999,104(B12) .29485-29508
[22] 高晋占.微弱信号检测.北京:清华大学出版社,2004
Gao J Z.Detection of Weak Signals(in Chinese).Beijing:Tsinghua University Press,2004
[23] Korpi G K,de Bruyn P L.Measurement of streaming potentials.J.Colloid Interface Sci.,1972,40(2) :263-266
[24] FinnoRJ,Chung K,Yin J,et al.Coefficient of permeability from AC electroosmosis experiments.Ⅱ:Results.J.Geophys.Engrg.,1996,122(5) :355-364
[25] Pride S R,Morgan F D.Electrokinetic dissipation induced by seismic waves.Geophysics,1991,56(7) :914-925
[26] 高永新,胡恒山.水平分层孔隙介质中点源激发的震电波场数值模拟及分析.地球物理学报,2009,52(8) :2093～2104
Gao Y X,Hu H S.Numerical simulation and analysis of seismoelectromagnetic wave fields excited by a point source in layered porous media.Chinese J.Geophys.(in Chinese),2009,52(8) :2093～2104
[27] 胡恒山,刘家琦,王洪滨等.基于简化的Pride理论模拟声电效应测井响应.地球物理学报,2003,46(2) :259～264
Hu H S,Liu J Q,Wang H B,et al.Simulation of acousto-electric well logging based on simplified pride equations.Chinese J.Geophys.(in Chinese),2003,46(2) :259-264
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