电场作用下裂缝介质单相渗流数值模拟

NUMERICAL SIMULATION OF SINGLE-PHASE FLOW THROUGH POROUS MEDIA IN FRACTURE MEDIA UNDER ELECTRIC FIELD

建立了电场作用下裂缝介质单相流体渗流的数学模型,设计了3个不同张开度的裂缝介质模型,采用有限元方法,通过数值模拟研究了电场强度、压力梯度及裂缝张开度对渗流速度的影响。结果表明:(1)在一定条件下电场能有效地提高裂缝介质的渗流速度,电场强度越大,裂缝介质中渗流速度越大,在张开度为5×10-5m的裂缝介质中,电场强度为450V/m时,渗流速度可提高8.2倍;(2)有、无电场作用时渗流速度之比随压力梯度增大呈指数衰减规律变化,压力梯度越小,电场对裂缝介质的渗流速度影响越大;(3)在张开度小、渗透率低的裂缝介质中,电场对渗流速度的影响大。

The single-phase flow through porous media in fracture media under electric field is studied with numerical simulation.A mathematical model describing the flow of single-phase fluid in fracture media under electric field is established based on the equivalent continuum model and the electroosmosis theory,the finite element method for solving the mathematical equations is introduced,three kinds of fracture media models with different fracture apertures are designed,and the effect of electric-field strength,pressure gradient and fracture aperture on flow velocity in fracture media is analyzed respectively in terms of the numerical results.The flow rate can be increased effectively under electric-field,for example,the velocity can be increased by 8.2 times in the fracture media whose aperture is 5×10-5m when electric-field strength is 450v/m,and the ratio of flow velocity under different electrical fields and zero electrical field decays exponentially with pressure gradient increasing.The results indicate that influence of electric field on flow through porous media is more significant with the decreasing in the pressure gradient and the fracture aperture.