During last decades the major companies increasingly exploit such hydrocarbon resources as heavy oil, bitumen or oil shale. The production of oil from such reservoirs is frequently done through reservoir heating, most often via steam injection. However it becomes more and more evident that for some cases there exist better suited technologies and one of them is the electromagnetic (EM) heating assisted oil recovery. According to the EM field frequency different physical mechanisms may underlie the heat release. The radio-frequency (RFH) or dielectric heat generation results from rotation with friction of polar molecules in the EM field. The advantages of the RFH-based technology are related to the in-situ heating and steam generation from the connate water which eliminates the problems associated with low well injectivity, well injection pressure, the water supply and hence, the water treatment etc. They include also the possibility to apply the heating in shallow or thin reservoirs and also in case of initially mobile heavy oil to optimize the production efficiency using both principal production mechanisms: the gravity drainage and the steam drive. The large-scale RFH models have been recently developed for numerical simulation of realistic EM power distributions. These models provide a means to critically analyze the processes of oil recovery. In the current study we take advantage of two dedicated simulators and the methodology of loose coupling between them to deliver the calculated EM heating power field to dedicated reservoir simulator. The combination and competition between two principal production mechanisms for different well patterns, spacing and orientation are considered; their influence together with other operational conditions impact on the efficiency and application limits of the oil recovery method are analyzed. The analysis of different mechanisms of RFH assisted heavy oil production is an important feature in process design considerations.

Being the most popular technological framework for the heavy oil and bitumen production, the reservoir heating is mainly performed via steam injection. Progressively it becomes evident, however, that there exist other methods offering an efficient production for various initial reservoir conditions and oil properties. The electromagnetic (EM) heating assisted oil recovery is one of them capable to be an alternative to conventional approaches where they become inacceptable.Physically speaking the radio-frequency (RF) heat generation results from so-called microwave effect i.e. rotation with friction of polar molecules in the EM field. The intrinsic advantages of the RF-heating (RFH) based technology, which in particular avoids the problems associated to water supply and water treatment, can be strengthened by solvent injection. After certain period of preheating this may lead directly to improved oil recovery due to additional oil viscosity drop as a result of oil-solvent mixture process. Along with this the solvent injection may reduce the operational in-situ temperature and thus, to increase the energy efficiency (i.e. the amount of energy required per unit of oil production). This will open a way to the successful technology application in shallow and/or thin reservoir. Mention also that the combination of heat and solvent supply has recently been field-tested.Recently the large-scale EM heating models have been developed for numerical simulation of realistic RFH applications, which provided the technical basis for critical analysis of the oil recovery processes. The numerical methodology based on loose coupling between dedicated reservoir and electromagnetic simulators, has been applied to study the combination (and competition) of two principal physical mechanisms of oil viscosity reduction associated with heat and solvent mass transfer. Taking advantage of the field-scale modelling the evaluation of operational conditions providing the oil production efficiency has been done. It was shown that RFH and its modification can be efficient for the various reservoir conditions. Noticeably different solutions for well configurations can be envisaged in the technology under consideration.The simulations have included the pure RFH cases at variable total EM power and the RFH combination with solvent injection at different operational and well. The initial reservoir conditions and properties corresponded to typical Athabasca reservoir. Main results comprising the methodological aspects of the recent 3D code development, the conclusions on pure RFH advantages and drawbacks and the demonstration of enhanced oil recovery efficiency at solvent injection within the RFH framework, are presented in detail. The role of particular mass transfer mechanisms and their contribution to improved process efficiency in heterogeneous matrix are quantified and discussed.The solvent injection combination with electromagnetic (radio-freqency) heating may become a promising issue in many practical applications.