The depletion of conventional oil reserves creates a significant demand for the development and improvement of methods and technologies for the production of hard-to-recover oil. A huge potential for hard-to-recover oil in Western Siberia lies in the Pokur suite (PK). These deposits are characterized by high oil viscosity and, accordingly, early water breakthrough. This study identifies and substantiates an effective technology for oil production from such and similar deposits using polymer flooding. The obtained data are based on research of the geological structure, the main reservoir properties and those of its fluids, chemical and laboratory methods of analysis, and the results of mathematical and hydrodynamic modeling. According to the results of hydrodynamic modeling, the greatest technological effect of polymeric water flooding is observed in the model of collector permeability at 70 mD and above 1000 mD, but this technology is not recommended for reservoirs with an average permeability of less than 10 mD. Implementation of the best practices through the prism of the resource nexus allows sustainable water management by applying environment-friendly polymers for enhanced oil recovery and contributes to the UN Goal 6 of clean water and sanitation.

Despite the development of alternative energy sources, oil and gas still remain the predominant energy sources in most countries in the world. Due to gradual hydrocarbon reserve depletion and the existing downward trend in the production level, there is a need to search for methods and technical approaches to level off the falling rates. Chemically enhanced oil recovery methods (EOR) by surfactant solution injections are one of the possible approaches for addressing this issue in already developed fields. Most often, surfactants are injected together with polymers or alkalis. These technologies are called surfactant–polymer (SP) and alkali–surfactant–polymer (ASP) flooding. Basically, SP and ASP have been distributed in China and Canada. In this article, in addition to these countries, we paid attention to the results of pilot and full-scale tests of SP and ASP in Russia, Hungary, and Oman. This study was a comprehensive overview of laboratory and field tests of surfactant solutions used for oil displacement in SP and ASP technologies. The first part of the article discussed the physical fundamentals of the interaction of oil with surfactants. The second part presented the main chemical reagents used to increase oil recovery. In the third part, we described the main facilities used for the preparation and injection of surfactants. Further, the results of field tests of SP and ASP in the abovementioned countries were considered. In the discussion part, based on the considered results, the main issues and uncertainties were identified, based on which some recommendations were proposed for improving the process of preparation and injection of surfactants to increase oil recovery. In particular, we identified an area of additional laboratory and scientifically practical research. The outcomes of this work will provide a clearer picture of SP and ASP, as well as information about their limitations, current challenges, and potential paths forward for the development of these technologies from an economic and technological point of view.

Currently, there is a worldwide decline in the level of production while maintaining the level of consumption. At the same time, the newly discovered fields are not able to compensate for the volumes of extracted oil, since the volumes of reserves are mainly small or medium. In this regard, it is relevant to introduce technologies to increase oil recovery at already drilled and developed fields. A promising method of increasing oil recovery is polymer flooding, which has many years of successful experience in both Russia and abroad. Polymer flooding technology consists in adding dry polymer to the injected water in concentrations from 0.05 to 0.25 % in order to increase its viscosity, which in turn contributes to improving the flooding process. The polymer rim equalizes the ratio of mobility in the reservoir and allows oil to be uniformly displaced from reservoirs in which there is a heterogeneity in permeability. The key result in the implementation of the technology is an increase in the oil recovery coefficient by improving the coverage of the reservoir by the flooding process, as well as a gradual increase in water availability, without early water breakthroughs from injection to production wells. This technology has wide limits of applicability and has already proven its effectiveness in various geological and physical conditions. This article will consider the physical basis of exposure, the principle of action, the criteria of applicability, the main groups of chemical reagents, and the accumulated domestic and international experience in the design and implementation of polymer flooding technology, development trends and the main difficulties associated with the introduction of this technology.