Release:
2018, Vol. 4. №4About the authors:
Nikolay N. Ivantsov, Expert, Tyumen Petroleum Research Center, Rosneft; nnivantsov@tnnc.rosneft.ruAbstract:
When developing high-viscosity oil fields, geological conditions have a decisive influence on the choice of the enhanced-oil recovery (EOR) method. Currently, chemical methods are being studied for the PK1-7 layers of the Russkoye gas-oil field.
Modeling of chemical EOR method for high-viscosity oil fields requires the use of detailed sector models, which take into account all the key physical processes. The field is divided into characteristic zones, which have significant differences in the parameters, which are critical for the simulation of the corresponding technology. A sector model is built in each zone.
Taking into account laboratory studies, a set of data for the simulation of polymer flooding was formed. In the absence of their own research, the authors propose a scheme for preparing initial data for ASP modeling. In particular, relative permeabilities are prepared depending on the capillary number, which allows to take into account the combined effect of any combination of components and their concentrations.
A significant amount of computational experiments with injection of polymer and ASP solutions was performed. Among other things, that included the issues of optimal concentrations of different agents, the start time and duration of their injection depending on the geological conditions and the degree of water cut, the optimal well placement, sensitivity analysis and economic assessment.
The injection of polymer solutions leads to a decrease in water cut and an increase in oil production in comparison with the water injection option. The increase in production is constrained by the restriction on bottom-hole pressure — the use of target concentrations leads to delayed additional production and reduced profitability, while the fall in reservoir pressure is recorded due to low compensation by injection. The optimal scheme of realization of polymer flooding in these conditions is proposed.
ASP flooding showed technological efficiency for the Russian field in comparison with water/polymer injection. However, in the current economic conditions, the method is unprofitable.
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