Abstract:
© 2018 Neftyanoe Khozyaistvo. All rights reserved. At present, great attention is paid to the study of the heavy crude oils and natural bitumens transformation occurring in the conditions of their extraction by steam-thermal methods acting on carbonate reservoir. The steam-assisted gravity drainage is a cost effective method for increasing the production of superviscous oil and providing access to reserves that were previously considered to be unrecoverable. Thermal methods of heavy oil recovery lead to various changes in the physical and chemical properties of the extracted crude oil. The same steam-thermal method can be highly efficient in certain reservoir conditions, while in others, its efficiency is zero or even negative. The knowledge of the peculiarities of the super-viscous oil structure and composition change after the steam-thermal method effect on the petroleum rock becomes necessary to select the most effective steam-thermal technology for specific conditions of the reservoir. The paper considers the influence of rock-forming minerals on the physical and chemical properties of heavy crude oil under steam-stimulation. Biodegrade oil was performed in the presence of rock-forming additives among which are calcites, dolomite, kaolin clay and manganese oxide. In the experiments we varied temperature and pressure conditions. It was observed, that the temperature and pressure have a significant influence on the processes. The obtained samples after the steam-thermal stimulation characterizes by the lower structural and Newtonian flow viscosity, by great output of fuel and oil fractions than the heavy oil. Resins converted into lighter components during the destruction. The steam stimulation destruction of high molecular compounds of oil occurs on the surface of the mineral additives with the large surface area of the catalyst capable of fiction. On the surface, additives partially structure a monomolecular surface layer with a decrease in entropy of the observed molecules. This leads to a shift in the equilibrium towards the unimolecular reaction of thermal decomposition of -C-C-bonds by radical chain mechanism. Thus, there are two competing mechanisms. On the one hand, the temperature increase raises processes of macromolecular compounds cracking, from the other hand growing temperature background in the absence of high pressure reduces the probability of adsorption on to the additive surface.
