PAC-R — also called PAC-HV — is polyanionic cellulose in its high-viscosity grade. It cuts fluid loss and adds viscosity to the water phase from a single product. Ironstone supplies drilling-grade PAC-R with a certificate of analysis for every batch.
PAC-R does two jobs at once: it reduces API fluid loss by building a thin, low-permeability filter cake, and it raises the viscosity of the water phase. That makes it the choice for simpler water-based programs and top-hole sections where you want body and filtration control from one product. Like all polyanionic cellulose, it tolerates salt and hardness far better than technical-grade cellulose, so it keeps performing in seawater and brine.
Choose PAC-R (high viscosity) when you want viscosity and filtration control together — for example a low-solids water-based mud that needs body. Choose PAC-LV (low viscosity) when the mud is already at target rheology and you only want the filtrate down without thickening it. Both are the same polymer chemistry at different viscosity levels, so the filtration performance is comparable; the difference is how much viscosity each adds.
| Parameter | Typical value | Basis |
|---|---|---|
| Appearance | Off-white free-flowing powder | Visual |
| Moisture | ≤ 10% | — |
| Degree of substitution | ≥ 0.90 | — |
| pH (1% solution) | 6 – 8 | — |
| Apparent viscosity | High-viscosity grade (HV/R) | Rotational viscometer |
| API fluid loss | Meets API Spec 13A for PAC-HV | API filter press |
| Particle size | Stated on the certificate of analysis | Sieve |
Typical drilling-grade values. The certificate of analysis states the exact figures for each batch, reported against the API Spec 13A test procedures with the edition noted.
As with any cellulose polymer, dosage is set by pilot testing against your filtrate and viscosity targets in your own base fluid, then scaled to the system volume. Because PAC-R adds viscosity, watch the rheology as you treat so you do not overshoot. We include the technical data sheet with dosage guidance when we quote.
Indicative CIF price on request; indicative FOB ranges appear in the monthly Price Letter. For a firm price, send your volume and port on WhatsApp.