## 4 Conclusions  
Studies have established that the rheological characteristics of sediment-gelling compositions are influenced by both the components included in them and the degree of salinity of formation water. In fresh water, due to the absence of calcium and magnesium ions, polymers have good solubility and the ability to increase the viscosity of solutions. As the concentration of the displacing agent increases, the viscosity of the solutions increases. The results obtained in this chapter lead to the following conclusions:  
1. The viscosity of SGCs prepared with fresh water is higher than the viscosity of SGCs prepared with brine water.
2. It is shown that the physicochemical properties and the nature of the flow of sediment-gelling compositions depend on the concentrations of the polymer and alkali, the temperature, and the salinity of water, and at low polymer concentrations, the composition exhibits a Newtonian character.
* When alkali prepared in fresh water is added to SGCs, the salinity of the solvent increases and the viscosity of SGCs decreases. The addition of alkali to the collected formation water reduces the salinity of the solvent due to the precipitation of some of the salts, and therefore the viscosity of the SGCs increases.
* The physicochemical properties and the nature of the flow of sediment-gelling compositions depend on the concentrations of the polymer and alkali, the temperature, and the salinity of water, and at low concentrations of the polymer, the composition exhibits a Newtonian character.
* Simulation of the rheological characteristics of sediment-gelling compositions is carried out; taking into account the composition and medium concentration of various components (polymer, alkali), temperature and water salinity, expressions are obtained that characterize the dependence of rheological constants on temperature and on polymer and alkali concentrations.  
The obtained results of assessing changes in the rheological characteristics of SGCs depending on variations in temperature and polymer and alkali concentrations as well as data on the physicochemical properties and flow patterns of SGCs can later be used in practice in the case of using gel-forming systems in creating barrier waterproofing in bottom-hole wells, which will increase the efficiency of oil production and reduce the risk of watering. In this case, the proposed compositions of SGCs will improve oil recovery from reservoirs as well as reduce water inflows due to variations in rheological characteristics, and they also allow for the possibility of creating selective filterability in areas with high water saturation.  
Conceptualization, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K.; methodology, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K.; formal analysis, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K.; investigation, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K.; resources, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K.; writing--original draft preparation, review, and editing, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K.; visualization, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K.; supervision, G.Z.M., G.M.E., S.R.T., Z.B.I. and A.L.K. All authors have read and agreed to the published version of the manuscript.  
This study was financially supported by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (N* AP19674847).  
Not applicable.  
The authors declare no conflict of interest.