Viscosity is a major obstacle in the recovery of low API gravity oil resources from heavy oil and bitumen reservoirs. While thermal recovery is usually considered the most effective method for lowering viscosity, for some reservoirs introducing heat with commonly implemented thermal methods is not recommended. For these types of reservoirs, electromagnetic heating is the recommended solution. Electromagnetic heating targets part of the reservoir instead of heating the bulk of the reservoir, which means that the targeted area can be heated up more effectively and with lower heat losses than with other thermal methods. Electromagnetic heating is still relatively new and is not widely used as an alternate or addition to traditional thermal recovery methods. However, studies are being conducted and new technologies proposed that could help increase its use. Therefore, the objective of this study is to investigate the recovery of heavy oil and bitumen reservoirs by electromagnetic heating through the review of existing laboratory studies and field trials.

Summary This study investigates the effect of clay type on the performance variations of steam-assisted gravity drainage (SAGD). Two SAGD experiments at identical experimental conditions were conducted. The reservoir rock for the first experiment (SAGD1) is prepared with a sand (85 wt%) and kaolinite (15 wt%) mixture, and the second experiment (SAGD2) is prepared with a sand (85 wt%), kaolinite (13.5 wt%), and illite (1.5 wt%) mixture. The effectiveness of the steam-chamber growth did not change with the clay type; however, 15-wt% reduction in oil recovery was observed for SAGD2. The possible reasons were investigated with the analyses on the produced-water, the produced-oil, and the spent-rock samples. Contact-angle, particle-size, zeta-potential, and interfacial-tension measurements were carried out on the samples. The mineralogical changes on spent-rock samples were determined by X-ray diffraction (XRD) and scanning-electron-microscope (SEM) analyses. The contact-angle measurements on the spent-rock samples displayed the higher oil-wetness for SAGD2 than SAGD1. However, the water-wetness of illite is known to be higher than that of kaolinite. This unexpected result is explained by the interaction of illite and the asphaltenes from SAGD2. The particle-size measurements, along with the SEM images, on post-mortem samples reveal that illite containing clay exhibits cementation behaviour and, hence, reduces the permeability of the rock. According to the experimental results, we developed hypotheses to understand the bitumen/illite and bitumen/kaolinite interactions for SAGD. Because of the high water-wetness of illite, illite particles first interact with water. This interaction results in cementation and forms illite lumps with sand. Then, illite lumps continue to interact more vigorously with the polar molecules (water, asphaltenes, and resins). Clay migration and production occur in both clay types; however, while kaolinite is produced in the water phase, illite-containing clay as a result of its interaction with asphaltenes is produced in the oil phase.

Steam Assisted Gravity Drainage (SAGD) is a proven enhanced oil recovery technique for oil sand extraction. However, the environmental and economic challenges associated with steam generation limit the application of this technology. To address these issues, we investigated the effectiveness of Expanding Solvent SAGD (ES-SAGD) over base SAGD on a bitumen sample (8.8 °API). Experimental studies are conducted with a two-dimensional physical model. Different strategies for solvent injection are tested (co-injection and cyclic injection) to examine the deposition of polar fractions of the bitumen on porous media or producing polar fractions with non-polar ones. To investigate the level of oil upgrading while toluene is used as asphaltene soluble solvent, n-hexane was selected as asphaltene insoluble. Steam chamber development is monitored with temperature profiles from 47 separate positions. Steam oil ratios, solvent oil ratios, and the level of oil upgrading in terms of viscosity reduction and API gravity improvement are evaluated together. Environmental footprints of SAGD with ES-SAGD are discussed in terms of solvent toxicity, total produced greenhouse gases, and asphaltene precipitation with FTIR analysis on postmortem samples. Furthermore, the energy intensity of the processes is assessed by considering steam generation and solvent costs. This study reveals that co-injection of hydrocarbon solvents with steam enhances the steam chamber development with higher oil production rate. Moreover, ES-SAGD results in recovery of more upgraded oil and has less environment impact. We observe that the selection of the solvent type and injection strategy are the most crucial parameters for the design of hybrid SAGD process and solvent cost can be minimized by using the recycled solvent for continuous injection of solvents. High energy consumption for steam generation during SAGD process can be reduced by co-injection with steam proper solvent type at proper injection strategy. This experimental study reveals that ES-SAGD process has environmental and economic benefits over base SAGD. However, some solvents can cause undesirable effects due to the asphaltene destabilization and precipitation in production or transportation lines. Results of this work can be used to better address solvent interaction with polar components during SAGD.