In todays’ world, there is an increasing number of mature oil fields every year, a phenomenon that is leading to the development of more elegant enhanced oil recovery (EOR) technologies that are potentially effective for reservoir profile modification. The technology of conformance control using crosslinked microgels is one the newest trends that is gaining momentum every year. This is due to the simplicity of the treatment process and its management, as well as the guaranteed effect in the case of the correct well candidate selection. We identified the following varieties of microgels: microspheres, thermo- and pH-responsible microgels, thin fracture of preformed particle gels, colloidal dispersed gels. In this publication, we try to combine the available chemical aspects of microgel production with the practical features of their application at oil production facilities. The purpose of this publication is to gather available information about microgels (synthesis method, monomers) and to explore world experience in microgel application for enhanced oil recovery. This article will be of great benefit to specialists engaged in polymer technologies at the initial stage of microgel development.

On the example of an oil deposit of the Vereisk age which is one of the deposits in the Volga-Urals, lithotypes of rocks are distinguished, characterized by a fundamentally different structure of the void space. For selected lithotypes experiments were carried out on core samples with a change in the stress state of rocks under conditions of volumetric (pseudo-triaxial) compression. The pressure created in the experiments is identified with the development of processes at a distance from the epicenter of the hydraulic fractures appearance. Core samples were studied before and after exposure by non-destructive testing methods. The study of the sample structures by standard and tomographic methods did not allow us to establish significant changes during loading of the samples. At the same time, some increase in rock permeability was established in experiments. With this in mind, the samples were studied according to a technique specially developed by the authors using electron microscopy. The use of microscopic studies made it possible to obtain quantitative information about the change in the void space at a level inaccessible to X-ray tomography. As a result, it was found that both for potential reservoirs and for impermeable rocks, there is an increase in the length and opening of pre-existing fractures, which can be considered as the formation of additional effective fluid filtration channels. The experiments performed have changed the idea of ​​the process of hydraulic fracture development and can be used in geological and technological calculations.