PAC vs CMC in Drilling Fluids
PAC and CMC are both cellulose-based drilling-fluid additives used for filtration and rheology control, but grade, substitution level, viscosity contribution and tolerance to water chemistry can lead to different field performance.
PAC LV
Selected when fluid-loss control is required with a comparatively limited viscosity increase.
PAC HV
Selected when filtration control must be combined with a stronger viscosity and carrying-capacity contribution.
CMC
Often used as an economical filtration-control option in compatible water-based systems where the required grade and water chemistry are suitable.
How to compare them
Test the actual make-up water and full mud formulation. Compare fluid loss, rheology, hydration, salt/hardness response, solids interaction and temperature rather than selecting only from polymer name or brochure viscosity.