SS-1 is a copolymer which is synthesized by sulfonated lignitic material, hydrolyzed polyacrylonitrile and sulfonated phenol formaldehyde. The product has good adsorption and hydration ability, which can plug micro-fracture effectively, form dense mud cake with good compressibility, and maintain wellborn stable and protect reservoir. SS-1 is applicable for freshwater drilling fluid with pH of 7.5 to 9.5.
