APPLICATION OF POLYMER FLOODING IN HIGH SALINITY CONDITIONS IN UZEN FIELD

Abstract

This research investigates improved oil production techniques for high-salinity oil reservesfocusing on Uzen Field in Kazakhstan. According to standard primary and secondary recoverypractices current operations in mature reservoirs recover only limited quantities of the initial oilbefore EOR techniques become essential. Polymer flooding represents an advanced EOR methodwhich offers successful viscosity increase for water injection which leads to superior sweepefficiency together with reduced water output. The extreme salinity of formation water in the Uzen Field (TDS reaches 60,000 ppm) createsconditions that degrade polymers and decreases their viscosity. Through lab experimentsdeveloped for real reservoir conditions this research thoroughly screened polymer materialsutilizing hydrolyzed polyacrylamide (HPAM) as the main focus. The study performed laboratorywork by conducting tests for rheology and thermal stability and static adsorption and injectivitytesting. Additionally, ion modification experiments were performed to determine the effects ofselectively adding Na2SO4, CaCl2, and MgCl2 on polymer performance without altering the overallsalinity of the formation water. As evidenced through experimental testing appropriate control of ions results in majorimprovements of polymer stability alongside maintaining viscosity levels. The addition of 4× Mg²⁺ions produced better injectability by generating elevated resistance factors and decreased viscosityloss during core flooding assessments. A high Ca²⁺ content affected the repeated configurations ofpolymer chains which caused viscosity levels to deteriorate. The addition of measured Na2SO4amounts that rose sulfate concentration moderately strengthened polymer performance yet raisingthe amount too high decreased viscosity by damaging the polymer chain structure. Multiple studiesincluding Jouenne (2020) and Saha et al.(2021) and Hu et al.(2024) confirm that achieving theright balance of ions is essential for optimizing polymer flooding operations under high-salinityconditions. Field research conducted at Daqing, Shengli, Mangala, Pelican Lake, and Burgan locations aroundthe world validates how polymer flooding solves high water cut conditions in heterogeneousreservoirs. The examples show that proper polymer choice together with customized ion controlstrategies result in significant enhancement of oil recovery when dealing with challenging extremereservoir conditions. The study introduces an effective method to enhance polymer performance which mergeslaboratory testing methods with ion modification techniques. The obtained results help understandpolymer flooding techniques while providing essential discoveries for enhancing Uzen Field oilextraction. Follow-up pilot testing combined with sustained monitoring should be conducted toimprove polymer formulation methods and injection practices leading to efficient sustainable EOR operations.