硼砂交联PVA降失水剂的合成及滤失性能研究

Study on Synthesis and Filtration Properties of PVA-Based Fluid Loss Reducer Crosslinked by Borax

以聚乙烯醇(PVA1788)为水泥浆降失水剂基础原料,考察了交联剂种类和用量、反应温度、溶液pH值等对PVA胶液粘度和水泥浆滤失性能的影响规律,发现硼砂水解后对PVA的交联效果最显著,而且随着硼砂与PVA配比、反应温度和pH值升高,PVA胶液粘度及水泥浆滤失性能呈现显著增高趋势,所形成的滤饼更加致密,保水能力更好。但一旦超过最佳配比时,水泥颗粒表面降滤失剂膜层变厚,滤饼致密性变差,反而不利于水泥浆保水,滤失性能下降。

Using polyvinyl alcohol(PVA1788)as the base material of cementing fluid loss reducer in cement slurry,the effects of the types and contents of crosslinking agents,the temperature and the pH value on the viscosity of PVA solution and the filtration performance of cement slurry were investigated.It was found that borax had the most significant crosslinking effect on the PVA solution.With the increasing of the ratios of borax and PVA,the temperature and the pH value,the viscosity of PVA solution and the filtration performance of cement slurry showed a significant increase tendency.Remarkably,the filter cake became denser to present highly enhanced water retention ability.However,once the optimal dosage was exceeded,the film layer of fluid loss reducer on the surface of cementing particles would become thicker,and the density of filter cake became worse,which was not conducive to the water retention of cement slurry and the filtration performance decreases.