To address the lack of understanding of the electrokinetic phenomenon of the electric double layers at the surface of tight reservoirs under an external electric field and the difficulty in accurately characterizing the micro-characteristics of the interfacial electric double layers through macroscopic experiments,this study investigated the impact of the electrokinetic phenomenon of electric double layers on wettability and crude oil seepage under an external electric field from a microscopic perspective, established a model of the electric double layers on the surface of tight reservoirs under an external electric field by employing the molecular dynamics simulation to explore the influence mechanism of the electric double layers on the surface of tight reservoirs at 313 K and 20 MPa.The analysis results indicate that:after the application of an electric field, the diffusion of solution ions is reduced,the electric double layers undergo expansion,and the electrostatic interactions on the charged surfaces lead to a thicker and more stable water film, which is beneficial for the water wettability of rock surfaces.The greater the electric field intensity, the higher the ion density in the electric double layers,and the more pronounced the electroviscous effect.The oil-phase seepage velocity increases due to the interfacial viscous resistance,but the increase is limited.The formation water solution internally produces a stronger ion hydration effect under the electric field,and changes in ion hydration occur with different ions when the electric field intensity is altered.The research findings are of significant importance for the development of micro-theories of tight reservoirs under external electric fields.
YANG Shanshan
,
NING Zhengfu
,
LYU Fangtao
. Molecular simulation of electric double layers at tight reservoir surface under external electric field[J]. Special Oil & Gas Reservoirs, 2025
, 32(1)
: 106
-112
.
DOI: 10.3969/j.issn.1006-6535.2025.01.012
[1] 张宁生,吴新民.电化学采油及其作用机理综述[J].石油勘探与开发,1998,25(2):73-74.
ZHANG Ningsheng,WU Xinmin.A discussion on the electrochemical recovery method and its mechanism[J].Petroleum Exploration and Development,1998,25(2):73-74.
[2] 马兵.离子液体电润湿特性的分子动力学研究[D].吉林:东北电力大学,2019.
MA Bing.Molecular dynamics study on the electrowetting characteristics of ionic liquids[D].Jilin:Northeast Power University,2019.
[3] 王成法.水溶液中油滴和固体颗粒电动运动界面效应研究[D].大连:大连海事大学,2018.
WANG Chengfa.Research on the electrokinetic motion and interfacial effects of oil droplets and solid particles in aqueous solutions[D].Dalian:Dalian Maritime University,2018.
[4] PU Q,YUN J,TEMKIN H,et al.Ion-enrichment and ion-depletion effect of nanochannel structures[J].Nano Letters,2004,4(6):1099-1103.
[5] KARIMINEZHAD E,ELEKTOROWICZ M.Comparison of constant,pulsed,incremental and decremental direct current applications on solid-liquid phase separation in oil sediments[J].Journal of Hazardous Materials,2018,358:475-483.
[6] DAIGUJI H,YANG P,MAJUMDAR A.Ion transport in nanofluidic channels[J].Nano Letters,2004,4(1):137-142.
[7] STEIN D,KRUITHOF M,DEKKER C.Surface-charge-governed ion transport in nanofluidic channels[J].Physical Review Letters,2004,93(3):035901.
[8] GHAZANFARI E,SHRESTHA R A,MIROSHNIK A,et al.Electrically assisted liquid hydrocarbon transport in porous media[J].Electrochimica Acta,2012,86:185-191.
[9] 郭馨蔚,师永民,杨悦,等.鄂尔多斯盆地长6油层组致密储层影响因素分析[J].大庆石油地质与开发,2013,32(5):165-169.
GUO Xinwei,SHI Yongmin,YANG Yue,et al.Analysis on the influencing factors of the tight reservoirs of oil group Chang 6 in Ordos Basin[J].Petroleum Geology & Oilfield Development in Daqing,2013,32(5):165-169.
[10] PRAKASH S,ZAMBRANO H A,RANGHARAJAN K K,et al.Electrokinetic transport of monovalent and divalent cations in silica nanochannels[J].Microfluidics and Nanofluidics,2016,20:1-8.
[11] KAMA N K,CRISSON A R,WAGEMANN E,et al.Effect of an external electric field on capillary filling of water in hydrophilic silica nanochannels[J].Physical Chemistry Chemical Physics,2018,20(27):18262-18270.
[12] 万骞.石英表面水化膜的分子模拟[D].武汉:武汉科技大学,2014.
WAN Qian.Molecular simulation of quartz surface hydration films[D].Wuhan:Journal of Wuhan University of Science and Technology,2014.
[13] 黄艾香.周期性边界条件的一种处理方法[J].数值计算与计算机应用,1983,4(1):37-46.
HUANG Aixiang.A method for treating periodical boundary conditions[J].Journal on Numerical Methods and Computer Applications,1983,4(1):37-46.
[14] SONG F,MA L,FAN J,et al.Electro-wetting of a nanoscale water droplet on a polar solid surface in electric fields[J].Physical Chemistry Chemical Physics,2018,20(17):11987-11993.
[15] SUN H.Compass:an ab initio force-field optimized for condensed-phase applications overview with details on alkane and benzene compounds[J].The Journal of Physical Chemistry B,1998,102(38):7338-7364.
[16] ZHAN S,SU Y,JIN Z,et al.Effect of water film on oil flow in quartz nanopores from molecular perspectives[J].Fuel,2020,262:116560.
[17] SMITH A M,BORKOVEC M,TREFALT G.Forces between solid surfaces in aqueous electrolyte solutions[J].Advances in Colloid and Interface Science,2020,275:102078.
[18] 左启阳.非对称双电层对薄膜润滑性能影响的研究[D].广州:华南理工大学,2012.
ZUO Qiyang.Research on the influence of asymmetric double electric layers on thin film lubrication performance[D].Guangzhou:South China University of Technology,2012.
