A comparative study of oil sands preheating using electromagnetic waves, electrical heaters and steam circulation

Application of steam assisted gravity drainage (SAGD) requires a time period between three to six months to establish fluid communication between the horizontal wells in a well pair. During this period, conductive heating reduces the bitumen viscosity such that it turns fluid and producible. High frequency electromagnetic waves may be used to enhance the heating process by in situ generation of thermal energy resulting from polarization of electrically conductive molecules inside the oil sands. We present new analytical solutions for three different preheating (start-up) scenarios including: steam circulation in well-pairs, electrical heaters in both horizontal wells, and electromagnetic antenna in the injector and electrical heater in the producer. The three scenarios are compared based on the time required for bitumen mobilization and the energy usage. Results show that the electromagnetic heating (EMH) decreases the energy usage significantly. The findings reveal that EMH in the frequency range of 1-10 MHz results in temperatures in the vicinity of the well that are below the coke formation temperature and thus coke generation and formation damage can be minimized. These results find applications in pilot and field. scale implementation of EMH for recovery of bitumen from oil sands. (C) 2017 Elsevier Ltd. All rights reserved.