Fluid-loss control keeps the water phase of a drilling fluid from seeping into the formation. Ironstone supplies the three product classes that do this job — polyanionic cellulose (PAC), modified starch, and high-temperature synthetic polymers — each with a certificate of analysis for every batch.
As the fluid presses against a permeable formation, water tends to filter into the rock and leave the solids behind as a cake on the wellbore wall. A fluid-loss additive builds a thin, low-permeability filter cake so that very little water passes through. That matters for three reasons: it protects the formation from damage, it keeps the wellbore stable, and it stops the filter cake from growing thick enough to stick the drill string. The additive is measured by the API fluid-loss test — the milliliters of filtrate that pass through in 30 minutes under standard conditions.
| Class | Best for | Trade-off |
|---|---|---|
| Polyanionic cellulose (PAC) | Fresh water through saturated brine; low and high-viscosity grades let you control filtrate with or without adding viscosity. | Costs more than starch; a temperature limit around the mid-range of water-based mud. |
| Modified starch | The lowest-cost filtrate control, and the default in saturated-salt and high-hardness systems where charged polymers struggle. | Lower temperature ceiling; ferments without preservative in low-salinity systems. |
| High-temperature synthetic polymer | Deep, hot sections where PAC and starch break down and filtrate climbs. | The specialty-price option; used where the cheaper classes cannot survive. |
Temperature is the property that decides the class. Starch has the lowest ceiling, PAC sits in the middle, and purpose-built synthetic polymers reach the highest. The exact limit depends on the grade, the exposure time, and the system chemistry, so the honest rule is to match the additive to your bottom-hole temperature and the length of the section — not to a single published number. When we quote, we state the temperature rating the manufacturer certifies for the grade we are offering.
The powders ship in 25 kg multi-wall paper sacks, palletized and containerized for full or part-container loads. None of these three classes is a dangerous good for sea freight, which keeps the shipping straightforward. We quote CIF to your port with the pack size, minimum order, and lead time stated on the quotation.