Evaluation of electromagnetic heating for heavy oil recovery from Alaskan reservoirs

Traditional thermal methods for heavy oil recovery involve use of steam to heat the wellbore and the reservoir. While the steam-based methods are widely in use and are generally successful, they also have high energy requirements, are not very efficient, and have environmental concerns. In addition, these methods are not readily applicable in Alaska, which is estimated to contain 18 to 27 billion barrels of heavy oil. Steam injection into the Alaskan heavy oil reservoirs is logistically complex, and is not practical due to the presence of a thick layer of permafrost. Hence, alternative methods to heat these reservoirs have to be considered. The use of high frequency electromagnetic (EM) heating has been studied for a couple of decades now and is one of the approaches that has shown potential as a non-steam based thermal method for heavy oil recovery. Electromagnetic heating has several advantages over steam injection. The efficiency of steam injection is often limited by low formation permeability. Because EM energy is also absorbed by the formation, permeability of the formation is not as critical. Also, EM heating can be confined to the areas of interest and is easily controllable. This method seems to be ideally suited for the Alaskan heavy oil reservoirs as it does not entail steam injection through the permafrost. In this study, use of EM heating for heavy oil recovery was examined mathematically by using engineering and physics-based computational modules. Using the fluid flow and heat transfer applications on a radial well model, the effects of EM power levels and frequency on heat penetration into the reservoir, temperature, and oil production were evaluated. The results showed that EM heating can increase heavy oil production rates by more than 200% using only moderate power levels, and continuous oil production could be sustained without any need to shut the well for heat dissipation or "soaking". The use of EM heating appears to be a realistic approach towards developing Alaskan heavy oil reserves.