The influence of casing properties on performance of radio frequency heating for oil sands recovery

Abstract

Radio frequency heating is regarded as a novel approach for bitumen extraction from oil sands. In the field operations, the radio frequency device is installed inside casings and used to continuously emit electromagnetic waves into reservoir, achieving the conversion of electrical into thermal energy. Obviously, the casings are critical components because their properties determine whether the electromagnetic waves can be effectively radiated into the pay zone with less additional power loss. Therefore, the effect of casing properties on performance of radio frequency heating is investigated from the aspects of electrical power dissipation density and temperature distribution. In addition, oil extraction and electrical energy to oil ratio are also analyzed based on energy conversion. A mathematical model describing the whole heating process is established, which considers the thermos-physical properties, electrical behavior and hydrodynamic performance of reservoir. Moreover, a lab-scale heating apparatus is developed for simulating practical implementation of radio frequency heating method. Simulation values are validated by temperature data obtained from laboratory experiment. Calculation results indicate that as the decline of electrical conductivity and relative permittivity of the casings, the heating area expands, the oil recovery increases and electrical energy to oil ratio decreases. Accordingly, the application of the casings with low electrical conductivity and relative permittivity can contribute to improve the performance of radio frequency heating for oil sands recovery.