电磁场?渗流场耦合作用下离子液体多孔介质流动模型

离子液体是一类可调控、多功能的绿色环保材料, 具有良好的电磁场响应, 有望应用于调控水驱油路径. 在分析离子液体在毛细管中电磁场响应机理的基础上, 建立了电磁场?渗流场耦合作用下离子液体多孔介质流动模型. 通过理论推导与数值分析发现: 电磁场?渗流场耦合作用下毛细管流量大小主要由离子液体电导率与黏度的比值(内因)、电磁场强度与压力梯度(外因)两方面决定; 电磁场产生的洛伦兹力对离子液体施加一个电磁驱动压强, 形成一个类似压力梯度的电磁驱动等效压力梯度, 从而改变离子液体的流量, 当电磁场强度为2.0 × 104 V/m·T时, 电磁场在电导率为0.5 S/m的离子液体上可形成10 kPa/m电磁驱动等效压力梯度. 通过调整电磁场方向即可控制离子液体在多孔介质中的流动方向, 解决常规注水利用压力差难以控制流动路径的难题, 为离子液体智能驱油提供理论依据, 且电磁场产生的热效应会影响离子液体的流动能力及潜在驱油效率. 

FLOW MODEL OF IONIC LIQUIDS IN POROUS MEDIA UNDER COUPLED ELECTROMAGNETIC AND SEEPAGE FIELDS

Ionic liquids (ILs), as a class of green and environment-friendly materials, are adjustable and multifunctional. ILs have excellent electromagnetic field response, which hold a great promise for the adjustment of waterflooding pathway. In this paper, the electromagnetic response mechanism of ILs in capillary is firstly analyzed. Then a flow model of ILs in porous media under coupled electromagnetic and seepage fields is established. Finally, the theoretical derivation and numerical analysis results show that the capillary flow rate under coupled electromagnetic and seepage fields is mainly determined by the ratio of ILs conductivity to viscosity (internal factor), electromagnetic field strength and pressure gradient (external factors). The electromagnetic field generates an electromagnetic drive pressure on the ILs by Lorentz force, forming an electromagnetic drive equivalent pressure gradient analogous to the pressure gradient, thereby changing the flow rate of ILs. When the electromagnetic field strength is 2.0 × 104 V/m·T, the electromagnetic field can form a 10 kPa/m electromagnetic drive equivalent pressure gradient on an ILs with a conductivity of 0.5 S/m. Meantime, the flow direction of ILs in porous media can be controlled by adjusting the direction of electromagnetic field, which can solve the difficult problem of using pressure difference to control flow paths, and provides a theoretical basis for intelligent oil displacement of ILs. Furthermore, the thermal effect generated by the electromagnetic field will affect the flowing capacity of ILs and the oil displacement efficiency.