Digital Modelling will Help in the Underground Processing of Heavy Oil
A software package has been developed to predict the absorption of catalysts during oil displacement.
Kazan Federal University has developed a program for modeling the dynamic adsorption of water-soluble catalysts during oil displacement in digital cores. This is important for predicting the efficiency of in-situ processing of high-viscosity and extra-viscous oil (natural bitumen). The Devon news agency learned about this from a message from the press service of the Institute of Geology and Oil and Gas Technologies of KFU.
Water- or oil-soluble catalysts are needed for the partial processing of hydrocarbons and for improving the quality of heavy oil in reservoir conditions. The process of “upgrading oil” occurs in the fields under the steam-thermal effect of the catalyst. When they enter a porous medium, they can be subject to adsorption. During this phenomenon, catalyst particles are deposited on the surface of geological formations and absorbed by solids.
On the one hand, adsorption has a negative effect. A certain amount of catalyst is lost during deposition on the surface of the particles. On the other hand, adsorbed particles can be useful in the case of repeated thermal steam exposure accompanying the process of aquathermolysis.
“The novelty of our work lies in the fact that we consider dynamic adsorption in multiphase flows, that is, in the process of oil displacement,” explained Timur ZAKIROV, Associate Professor of the Department of Mathematical Methods in Geology at IGiNGT. – Before that, we were working with single-phase currents. The catalyst was dissolved in water and moved through the sample, which also contained water.”
KFU scientists used the Digital Core technology. They also developed a software package for modeling the processes of dynamic adsorption of catalysts under multiphase flow conditions. The mathematical model makes it possible to study both water- and oil-soluble catalysts. It takes into account all the most important development parameters, such as oil viscosity, interfacial tension, contact angle, etc.
Knowing the viscosity of oil and other field development parameters, it is possible to predict how much expensive catalyst will be lost as a result of adsorption. Under certain development parameters, in particular, at low interfacial tensions, a significant part of the catalyst is adsorbed on the surface of the particles. This will significantly reduce the efficiency of catalytic aquathermolysis.
“Based on the conducted studies, we will know in advance that under certain development parameters there will be big losses,” Zakirov said. “Then it doesn’t make sense to pump in the catalyst.” A number of customers have already shown interest in purchasing the software, he added.
Kazan scientists for the first time classified the modes of dynamic adsorption of a catalyst during oil displacement. At a low adsorption intensity, a decrease in the catalyst flow rate in the pore space contributes to an increase in the adsorbed amount. And at high intensity, the absorbed amount of catalyst is determined by the efficiency of oil displacement.
Scientists are studying the behavior of catalysts injected into the reservoir in a porous medium, explained Mikhail VARFOLOMEYEV, project manager, head of the department for the development and operation of hard-to-recover hydrocarbon deposits at IGiNGT.
“This is very important for predicting the efficiency of using the technology and selecting the optimal conditions for the use of reagents at a depth of up to 1,000 meters. he noted. “The patterns obtained in the course of mathematical calculations will make it possible to advance in solving this problem.”
In 2021, Kazan Federal University won the competition for grants from the Russian Science Foundation. A grant of 128 million rubles was allocated for the development of new technologies for catalytic underground upgrading of high-viscosity and extra-viscous oil. The project is designed for four years.
Devon recently reported that KFU has developed a kinetic model to predict the parameters of catalytic aquathermolysis at the Chinese Liaohe field. The work will make it possible to introduce a cost-effective and environmentally friendly technology for the production of heavy oil into industrial production.
Aquathermolysis is a process of high-temperature conversion of oil under the influence of water vapor. In-situ pressure catalysts developed by KFU are tested in Russia, Oman, Cuba and other countries.
