The Enhancement of a Low-Frequency Electrical Heating Method by Saltwater Circulation

Abstract

Low-frequency electrical heating is an effective method that can solve most of the problems of recover of highly viscous oil from a reservoir, such as low initial injectivity and shallow depth in launching common thermal injection processes. This technology has been recently field tested, yielding acceptable results. An associated important problem of electrical heating is the appearance of hot spots around the electrodes, which can be solved by water circulation. Furthermore, water circulation, in particular saltwater circulation, has a significant effect on the heating process due to the high electrical conductivity of the circulated water.In order to investigate the effect of saltwater circulation on process efficiency we studied the process using numerical simulation. The physical properties and operational data for Athabasca bitumen were collected from the literature. The model built using the CMG STARS simulator (Computer Modelling Group, Ltd., Calgary, Alberta, Canada) and tested with available analytical solutions was validated. The results indicate that the proper application of saltwater circulation in electrical heating methods dramatically influences the temperature propagation by increasing the electrical conductivity and extending the effective radius of the electrode, raising the heat convection and cooling the electrodes. After 3 years' simulation, a recovery factor of 40% was achieved.

Recent Advances in Methods of Gas Recovery from Hydrate-Bearing Sediments: A Review

“…It converts the electrical energy into thermal energy based on the resistance characteristics of HBS . For HBS, however, as one dielectric material, its resistivity must be reduced by the injection of electrolyte solutions such as NaCl solutions or conductive connate water located in the initial porous media to allow current applied to flow through the HBS and then generate resistance heat. ,, According to the current type, this method is driven by either a direct current (DC) or alternating current (AC). The DC power offers several advantages, including strong electrical power stabilization due to no periodic variation and cost-effective power transmission, which has become a common choice for obtaining Joule heat .…”