GCS PAC R (Polyanionic Cellulose – Regular Viscosity) is a high-performance polymer additive used in water-based drilling fluid systems for fluid loss control along with viscosity enhancement and rheology improvement. Unlike low-viscosity grades, PAC R is designed to provide both filtration control and viscosity building, making it suitable for drilling operations where improved suspension and carrying capacity are required.

When added to drilling fluids, PAC R hydrates rapidly and forms a strong, low-permeability filter cake on the wellbore wall, effectively reducing fluid loss into the formation. At the same time, it increases viscosity, helping to suspend drill cuttings and improve hole cleaning efficiency. This dual functionality enhances overall drilling performance, particularly in complex well conditions. PAC R is compatible with water-based mud (WBM) systems and performs reliably across a wide range of environments, including offshore, extended reach drilling (ERD), and moderate to high-temperature wells.