With the exploitation of ultra-high temperature deep wells, the fluid loss reducer as the core treatment agent of drilling fluid, in addition to ensuring the fluid loss performance, it needs to have both high temperature and high salt resistance and certain inhibition. Thus, N-(3-dimethylallyl)methacrylamide and 1,3-propane sultone were used to synthesize a betaine-type zwitterionic functional monomer named DMAPMAS. A zwitterionic copolymer PADAN as a fluid loss reducer for drilling fluids was prepared by attaching 2-acrylamide-2-methylpropanesulfonic acid, N-vinylpyrrolidone and synthetic DMAPMAS to the main chain of acrylamide via aqueous solution free radical polymerization. It not only has great thermal but has good fluid loss and inhibition performance. In addition, the addition of PADAN can effectively improve the particle size distribution of the drilling fluid system. The combination of PADAN and sulfonated polymer SMC, SMP-II and SPNH has the effect of reducing the fluid loss of drilling fluid. Moreover, it has good adaptability to a variety of drilling fluid systems. Applied to the sulfonation drilling fluid system and the polysulfide KCl drilling fluid system, it has the significant effect in fluid loss reduction and less impact on the rheological properties to adapt to various drilling fluid systems.

随着超高温深井的开发，减滤剂作为钻井液的核心处理剂，除了要保证滤失性能外，还需要兼具高温，高耐盐性和一定的抑制作用。因此，使用N-（3-二甲基烯丙基）甲基丙烯酰胺和1,3-丙烷磺内酯来合成甜菜碱型两性离子官能单体，称为DMAPMAS。通过将2-丙烯酰胺-2-甲基丙烷磺酸，N-乙烯基吡咯烷酮和合成的DMAPMAS通过水溶液自由基聚合连接到丙烯酰胺的主链上，制得两性离子共聚物PADAN作为钻井液的降滤失剂。它不仅具有出色的散热性能，而且具有良好的滤失和抑制性能。此外，添加PADAN可以有效改善钻井液系统的粒度分布。PADAN与磺化聚合物SMC，SMP-II和SPNH的组合可减少钻井液的漏失。而且，它对各种钻井液系统具有良好的适应性。应用于磺化钻井液系统和多硫化物KCl钻井液系统，对减少钻井液流失具有显着效果，对流变性能的影响较小，以适应各种钻井液系统。