Polyanion cellulose (Poly anioniccellulose) or PAC, is a water-soluble cellulose ether derivative made chemically modified by natural cellulose. It is an important water-soluble cellulose ether, a white or micro yellow powder, non-toxic, tasteless, it can be dissolved in water, has good heat stability and salt resistance, and strong antibacterial properties. The slurry fluid prepared by this product has good water loss, inhibition and high temperature resistance. It is widely used in oil drilling, especially salt wells and offshore oil drilling.