缓凝剂的选配是高温水泥浆体系设计最关键的因素之一.为了合理地优选和适用缓凝剂,选用AMPS-IA共聚缓凝剂与大连G级油井水泥作用,通过高温高压稠化仪、X射线衍射仪、扫描电子显微镜和能谱仪等对水泥稠化性能、水化硬化产物的物质组成和微观结构特征进行检测,对其适用性进行分析.结果表明:AMPS 类缓凝剂作为高温缓凝剂具有良好的缓凝效果,稠化线形好且稠化时间长.但是重复实验评价缓凝剂稳定性过程中有一定概率出现缓凝剂失效,稠化曲线出现波动,造成水泥浆异常胶凝.产生胶凝的原因是缓凝剂聚合物分子对阳离子产生螯合-吸附作用,在物理搅拌作用下使得大量聚合物分子与水泥熟料成胶联状聚集在搅拌轴外部.
The selection of retarder is one of the most critical factors in the design of high temperature cement slurry system.In order to reasonably select and apply the retarder,AMPS-IA copolymer retarder was used to react with Dalian G-grade oil well cement.The thickening performance of cement,the material composition and microstructure characteristics of hydration and hardening products were tested by high temperature and high pressure thickener,X-ray diffractometer,scanning electron microscope and energy spectrometer,and its applicability was analyzed.The results showed that AMPS retarders as high-temperature retarders had good retarding effect,good thickening line shape and long thickening time.However,in the process of repeated experiments to evaluate the stability of retarder,there was a certain probability that retarder failed,and the thickening curve fluctuated,resulting in abnormal gelation of cement slurry.Gelation was caused by the chelating-adsorption effect of retarder polymer molecules on cations,which caused a large number of polymer molecules to aggregate outside the gel.