Application of Electrical Current for Increasing the Flow Rate of Oil and Water in a Porous Medium

Abstract

Part II of their paper already published in the Journal of Canadian Petroleum Technology, Vol. 3, No. 1, pages 9–14, Spring, 1964: "Use of Direct Electrical Current for Increasing the Flow Rate of Reservoir Fluids During Petroleum Recovery." Abstract The possible use of direct electrical current for increasing the flow rate of reservoir fluids during petroleum recovery was recently investigated by Ambah et al. [1964] (29). As pointed out by the writers, however, thestudy of the application of electrokinetic phenomena in oil production was notcomplete, and many other problems remain to be solved. The possibility of using electric current for enhancing the injectivity ofwater in waterflood systems or simply increasing the rate of production intight formations was further investigated in the present study. In all cases, the volumetric rate of flow increased on increasing the electrical potential imposed. Additional theoretical analysis is also presented here. Theoretical Analysis Reuss [1808] (2) was the first to notice that if two electrodes were placedin a liquid on opposite sides of a porous diaphragm, on application of an electromotive force the liquid would flow from one compartment to the other. An equilibrium will be reached when the hydraulic head, due to the difference influid level, is balanced by the driving force caused by the imposed e.m.f. Wiedemann's [1852] (3) first and second laws stated that: When an electrical field is applied to a liquid in capillaries, the flowis proportional to the electric current or the applied potential. If, instead, this flow is prevented, the electroosmotic pressure is likewise proportional tothe current. Quincke [1860] (4) recognized electroosmosis and streaming potential as inverse phenomena and explained them by assuming the existence ofan electric double layer at the boundary surface between the liquid and thesolid wall. It can be assumed that the solid surface is negatively charged andthe positively charged part of the double layer is present in the liquid phase.Thus, upon the application of an external electrical field, the positivelycharged liquid layer will move toward the cathode, drawing with it watermolecules in the free liquid stream because of the viscous drag. Conversely, ifa liquid is forced through capillaries, a streaming potential or a streamingcurrent, depending on which is measured, is produced which is proportional tothe pressure differential applied.