high temperature and salt resistant drilling fluid filtration reduction TH-2500 is a high molecular weight organic polymer copolymerized by vinyl monomers containing anionic and non-ionic groups. Because its molecular chain contains a large number of temperature resistant and salt resistant calcium groups, it has a good function of temperature resistant and salt resistant calcium. It is a kind of drilling fluid loss reducer with excellent performance and wide application. It can also be used as tackifier of mud system.