Samples in the form of cylindrical plates, additively manufactured using the fused deposition modelling (or filament freeform fabrication, FDM/FFF) technology from polylactide (PLA), polyethylene terephthalate glycol (PETG) and polyetheretherketone (PEEK), were studied in series of in-vitro experiments on the adhesion of rat bone-marrow cells and rat peritoneal cells. Methods of estimation of the absolute number of cells and polymer samples’ mass change were used for the evaluation of cells adhesion, followed by the evaluation of cell-culture supernatants. The results of experiments for both types of cells demonstrated a statistically significant change in the absolute number of cells (variation from 44 to 119%) and the weight of the polymer samples (variation from 0.61 to 2.18%), depending on roughness of sample surface, controlled by a nozzle diameter of a 3D printer as well as printing layer height. It was found that more cells adhere to PLA samples with a larger nozzle diameter and layer height. For PETG samples, the results did not show a clear relationship between cell adhesion and printing parameters. For PEEK samples, on the contrary, adhesion to samples printed with a lower nozzle diameter (higher resolution) is better than to samples printed with a larger nozzle diameter (lower resolution). The difference in results for various polymers can be explained by their chemical structure.

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.

In order to reduce watering of wells and equalize their injectivity profiles, the prospects of introducing PPG technology in Russian fields are considered, in which preformed particles polymer gel are pumped into the injection well. These particles, being a supersorbent based on polyacrylamide, absorb water, become elastic, which allows them to shrink and tear in narrow filtration channels. When the polymer is filtered along permeable layers saturated with water, polymer particles accumulate in waterlogged intervals and thus they form a polymer plug, which redistributes the filtration flows and increases the coverage of the formation by the process of oil displacement.More than 4000 downhole operations have been carried out in the fields of China and the USA using PPG technology by now. In domestic fields in Western Siberia, there is limited experience in applying a similar technology in high-temperature formations with low mineralization of formation water. Due to the absence of hydrolytic processes in polyacrylamide, well-known domestic compositions are not applicable due to the low absorption capacity in the conditions of low-temperature deposits with increased mineralization of formation water.The authors synthesized a polymer based on polyacrylamide by block polymerization, which allows to obtain a high absorption capacity, including for low-temperature formations with high mineralization of formation water, which is typical for Perm Territory fields.Filtration experiments were carried out on core models with the composition developed by the authors, this composition focused on low formation temperatures and high mineralization of formation water. As a result of the experiments, it was found that the swollen particles of the gel are able to pass into fractures with a diameter less than their own size at least 20 times. With a significant increase in the viscosity of the dispersion medium, the stability of the suspension increases. Particles of polymer gel have the necessary strength for injection in the field conditions. The fracture permeability during polymer injection decreases by several times and becomes comparable with the permeability of pore collectors.

The relevance. Most fields of the Volga-Ural oil and gas province are characterized by high water cut of wells that determines the high demand of effective technologies for decreasing excess water production. For these purposes, preformed particle gel (PPG) technology is widely used abroad. However, for PPG application in domestic oil fields, it is necessary to take into account their geological and technological operating conditions. This problem is solved for conditions of low-temperature formations with high salinity of formation water. The publication presents the test results of the developed PPG polymer and standard polymer flooding on sandstone core. The main aim is to evaluate the possibility of injection of PPG into a terrigenous core, to conduct a comparative analysis of PPG treatment with traditional polymer flooding. Object: terrigenous cores of Perm deposits, a solution of a water-soluble polyacrylamide, PPG. Method. Filtration tests were carried out on the filtration installation UIK-5VG. The X-ray tomography method was used to estimate the pore space changing after PPG treatment and compare it with traditional polymer flooding. Results. The authors synthesized particles of a polymer gel (PPG technology) for reservoir conformance control. During application of PPG through the injection well the gel particles are able to move through the near well bore zone and block the high permeable reservoir zones, that leads to redistribution of water flows to the low-permeable zones. The composition of the polymer is adapted to the conditions of low-temperature formations with high salinity of formation water. The article presents the test results of the developed polymer on core models. The studies involved the data from the method of X-ray tomography of the core. The results of tomographic studies made it possible to visualize and quantitatively calculate the filling of the core pore space with a suspension, taking into account the size of individual pores. It was established that the developed polymer fills highly permeable intervals much more efficiently than standard polyacrylamide flooding.

Микрогели являются уникальным классом веществ, которые сочетают в себе свойства макромолекул, поверхностно-активных веществ и коллоидных частиц. Микрогели широко применяются для очистки сточных вод, в системах доставки лекарственных средств, для сушки биодизеля, в технологии регенерации тканей и имплантации, в хроматографии и др. На данный момент разработаны такие методы синтеза микрогелей, как осадительная и суспензионная полимеризация, эмульсионный метод и др. Все эти методы фактически уже стали классикой синтеза микрогелей. Данная публикация является обзором работ по методике синтеза микрогелей на основе полиакриламида и его производных методом обратной эмульсии. Этот метод выбран в связи с рядом преимуществ, таких как высокая степень конверсии мономеров, возможность контроля гранулометрического состава частиц геля во время синтеза, упрощенная процедура сушки готового продукта и др. В статье описаны особенности синтеза, влияющие на размер и форму микрогелей, описаны основные факторы, которые необходимо предусмотреть при планировании синтеза в обратной эмульсии; показана разница между макроэмульсией, наноэмульсией и микроэмульсией. Также приведены особенности синтеза микрогеля на основе акриламида и его производных: приведены основные инициаторы свободно-радикальной полимеризации; мономеры, влияющие на свойства микрогеля. Данная статья может быть интересной специалистам, которые только начинают исследования в данном направлении. После изучения публикации читатель сможет спланировать и реализовать эксперимент по синтезу микрогелей на основе полиакриламида методом обратной эмульсии. Для цитирования: Бурин Д.А., Рожкова Ю.А., Казанцев А.Л. Основы метода синтеза микрогелей методом обратной эмульсии. Изв. вузов. Химия и хим. технология. 2023. Т. 66. Вып. 3. С. 6-17. DOI: 10.6060/ivkkt.20236603.6732.