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

摘要

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 lias 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., Calgaiy, 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 recoveiy factor of 40% was achieved.