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Underground coal gasification (UCG) as an efficient method for the conversion of the world's coal resources into energy, liquid fuels, and chemicals has attracted lots of attention in recent years. This paper is concerned with a feasibility study of the UCG process for Alberta reservoirs using the three-dimensional simulation of this process based on a unique porous media approach. The proposed approach combines the effects of heat, mass transport, and chemical reactions to achieve this goal. The Computer Modeling Group (CMG) software STARS is used for simulation. The geological structure including coal and layers interspersed between coal seams (claystone layers), the porosity/permeability variation, and the chemical processes with corresponding parameters are considered in the model. Chemical stoichiometry coefficients of the pyrolysis process are calculated from proximate and extended experimental data. Genetic algorithm and pattern search are used for parameter estimation. This model is developed to study UCG in deep coal seams and can be used for production prediction and optimization of the process. The simulation results, such as cavity formation, temperature profile, and gas composition at the producer, are presented. Finally, the results are analyzed on the basis of field pilot tests.

The main recovery mechanism in the solvent-based bitumen recovery processes is gravity drainage. The density of heated bitumen or diluted bitumen at operational conditions is required to predict the production rate and cumulative oil recovery. In this manuscript, the densities of bitumen, pentane, and their mixtures at different pentane weight fractions (0.05, 0.1, 0.2, 0.3, 0.4, and 0.5) have accurately been measured. The measurements were conducted under conditions applicable for both in situ recovery methods and pipeline transportation of heavy oil. The experiments were taken using Athabasca bitumen at temperatures varying from ambient up to 200 °C and at pressures up to 10 MPa. The volume change upon mixing for the mixtures is evaluated from the experimental results, and the influence of pressure, temperature, and solvent weight fraction on the volume change upon mixing and density is studied. The density data are also represented with three different approaches considering no volume change, excess volume, effective liquid densities, and equation of state. The results indicated that the mixture data are well-predicted using equation of state and effective liquid densities with average absolute relative deviations (AARD) of 0.55% and 0.57%, respectively.

The phase behavior and thermodynamic properties of heavy oil and bitumen are of crucial importance for their in situ recovery, pipeline transportation, and upgrading; however, bitumen is a complex mixture of organic compounds whose chemical structures are not well understood. Therefore, bitumen is commonly characterized as a mixture of pseudocomponents derived from experimental data. This manuscript is intended to characterize and define the thermodynamic properties of Alberta bitumens. It has been undertaken three specific objectives: the first is the characterization of the bitumen as a mixture of pseudocomponents. The second objective is calculation of the gas solubility of gas-saturated bitumens by using an equation of state (EOS). The final objective is the selection of a set of pseudocomponents that would be applicable for different types of bitumen; in other words, the pursuit of a universal set of pseudocomponents for an EOS, independent of bitumen type. Varying numbers of pseudocomponents have been tested against the experimental data in the literature for bitumen from different fields (Athabasca, Wabasca, Peace River, and Cold Lake) with four different solvents (CH4, C2H6, CO2, and N2). The results show that the Lee−Kesler correlation (Lee, B. I.; Kesler, M. G. AIChE J. 1975, 21, 510−527) has produced considerably better results than the other correlations; it also appears that the Lee−Kesler correlation is appropriate for bitumen/solvent systems to determine the critical properties of the pseudocomponents.