The high-pressure air injection on the oil-source rock of the Bazhenov formation has a great potential. However, before carrying out a pilot project on the field and making decisions on air injection regimes, it is necessary to build a hydrodynamic model in which a principal place will be occupied by a block of chemical reactions.
This study includes computer simulation of the high-pressure air injection process with using a thermal simulator CMG STARS. The numerical model was adjusted using the results of a combustion tube laboratory experiment. On account of the consolidated model of the combustion tube used in the experiment, a complex numerical 3D model with multiple local refinements of the grid was constructed. That significantly increases the calculation time and imposes a significant limitation on the possibility of carrying out a large number of numerical experiments, which are necessary for the construction of the kinetic model of chemical reactions. Therefore, the geometrical and physical model was simplified by decreasing the dimension of the grid and simplifying the boundary conditions used in the experiment. The before mentioned procedure describes the first level of the optimization workflow that was implemented as a part of this work. Thus, a simplified 1D model of the combustion tube was proposed and tested, which roughly describes the heterogeneity of the consolidated experimental model, but is appropriate for carrying out mass calculations.
As a result of the validation of the model, it was mainly possible to match the temperature profiles in different zones of combustion tube and the total volume of extracted products behind the combustion front. Also, the grid convergence test was performed, which is necessary to identify the dependence of the kinetic parameters on the size of the computational cells. As a result of the simulation, chemical reactions describing the combustion process were confirmed.
The obtained results are necessary for computer simulation of a full-scale oil recovery process by high-pressure air injection in a pilot project at the field.References
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