Creation of a New Oil-Displacing Composition Based on a Triple System of Deep Eutectic Solvents “Pentaerythritol - Urea - Choline Chloride” and Surfactants

The paper presents the results of creating a new oil-displacing composition based on the ternary system of deep eutectic solvents (DES) “pentaerythritol - urea - choline chloride” with surfactants, and the results of laboratory tests of its effect on the filtration characteristics of the heterogeneous formation of the Usinskoye field with heavy and high-viscosity oil. As a result of studying the physicochemical characteristics and phase equilibrium of the ternary DES system, a new oil-displacing composition of prolonged action was created, based on the ternary DES system “pentaerythritol - urea - choline chloride” and surfactant, applicable for various geological and physical conditions of fields, in particular in the Arctic zone of the Russian Federation. The effectiveness of the composition was assessed for sections of the field at the early and late stages of development. It has been established that the use of the composition based on DES and surfactants leads to the equalisation of filtration flows with an increase in formation coverage, restoration of the initial permeability and, as a consequence, to a significant increase in the oil displacement coefficient at both low and high temperatures.