The article evaluates the efficiency of injection of hydrocarbon gas, taking into account the risks of precipitation of asphaltene compounds. Experiments were carried out to determine the pressure of the onset of asphaltene precipitation when mixed with hydrocarbon gas and carbon dioxide. The oil-gas displacement ratio and the minimum miscibility pressure were preliminarily estimated on slim-tube tests and a core column displacement. In addition to the standard research program, tests of oil swelling, phase behavior of the fluid during the dissolution of the gases considered for injection in given volumes by filtration and microscopic methods were carried out for a number of prepared gas-oil mixtures. The obtained experimental data on the phase stability of asphaltenes were used to construct a calibration dependence of the dissolved asphaltenes in oil on the molar fraction of the added gas and were used for hydrodynamic modeling of the gas methods for EOR. The PVT model was adjusted to the results of laboratory studies using the SRK-Peneloux equation of state. During the model tuning, a pseudo-component of asphaltenes was isolated, which has the main properties of asphaltene hydrocarbons obtained from experimental data. The results of slim-tube experiments and core displacement experiments were replicated using hydrodynamic simulation to verify the tuned PVT fluid model. The PVT model is used for predictive calculations on the prepared sectoral hydrodynamic model with the modeling of asphaltene deposition during oil-gas mixing. Conclusions are drawn about the possibility and necessity of using the asphaltene precipitation model in the simulation of hydrocarbon gas injection. The results of the calculation showed significant changes in the technological indicators of the project implementation on the sectoral model.
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