Polyanionic Cellulose Polyanionic cellulose,PAC is chemically derived from natural cellulose e.g.wood or cotton linters.Polyanionic Cellulose has excellent heat-resistant stability, salt tolerance and strong capability of anti-bacterial contamination.The drilling slurry or fluid prepared from PAC has high performance in fluid loss reducing, injection capability and higher temperature tolerance. The PAC exhibits high performance in various salt resistance, including calcium,magnesium-resistance.It can reduce filtration loss. It can be used in all water based drilling fluids.