Factors Influencing Gelation Time of High Temperature Crosslinked Polymer Gel and Its Mathematical Function

Abstract

AbstractThe gelation time of high temperature crosslinked polymer gel is affected by the concentration of polymer, crosslinking agent and stabilizer, temperature, salinity and pH, etc. At present, it is mostly qualitative analysis and lack of quantitative characterization. In order to control the gelation time precisely, it is necessary to study the influences on the gelation time and establish mathematical function. In this paper, a static gelation experiment of high temperature crosslinked polymer gel was carried out according to the uniform design method, and the influence of the above six factors on the gelation time was studied. Then, a comprehensive mathematical function of gelation time covering the above six factors was established through the multiple nonlinear regression analysis. Finally, the influence degree of each factor on the gelation time was determined by the analytic hierarchy process (AHP) method. The results show that the gelation time is negatively related to temperature and the concentration of polymer, crosslinker and stabilizer. Low temperature is not conducive to gelation, and the gelation time is prolonged from 22 h to 159.6 h. What’s more, the gelation time is positively correlated with pH and salinity, but the relationship was not significant, which indicates that the gel system has good temperature and salt tolerance and acid-alkine resistance. The influence degree of the six factors on the gelation time from strong to weak is polymer concentration, crosslinking agent concentration, stabilizer concentration, temperature, salinity and pH. R-sq (the percentage of the fitted formula error to the total error) is 95.75%, and the adjusted R-sq is 97.58%, indicating that the fitted function is accurate and reliable. Therefore, the gelation time of the gel system can be accurately controlled to meet the requirements of delaying crosslinking on site, and thus provide certain guidance and reference for the design, optimization and performance prediction for the formula of the profile control and flooding system.KeywordsHigh temperature crosslinked polymer gelGelation timeInfluencing factorsMathematical function