Modified drilling starch is the lowest-cost filtration-control additive in water-based drilling, and the default in saturated-salt and high-hardness systems where charged polymers struggle. Ironstone supplies drilling-grade modified starch with a certificate of analysis for every batch.
Drilling starch reduces fluid loss. It is pregelatinized — processed to hydrate in cold water without cooking — so its swollen particles are soft and deformable: they lodge in the pores of the filter cake and deform to seal them, cutting the filtrate. Because starch is non-ionic — the molecule carries no charge — salt does not switch it off, which is why it remains the default filtration additive in saturated-salt and high-hardness systems.
Standard modified starch is the lowest-cost filtrate control for normal-temperature sections and short exposure times. Temperature-stabilized grades are additionally modified or cross-linked for deeper, hotter sections where standard starch degrades and the filtrate climbs mid-section. If your current product carries an “HT” suffix, the temperature-stabilized grade is the one to match. Starch is organic material, so every grade has a temperature ceiling and — especially in lower-salinity systems — can ferment if the mud sits uncirculated without preservative.
| Parameter | Typical value | Basis |
|---|---|---|
| Appearance | Off-white to pale-yellow powder | Manufacturer COA |
| Moisture | < 10% | Manufacturer COA |
| pH (2% solution) | 6.0 – 7.5 | Manufacturer COA |
| API fluid loss | ≤ 10 mL (in NaCl brine, per API Spec 13A) | Manufacturer COA (API 13A method) |
| Viscosity (600 r/min dial) | Low — starch adds filtration, not viscosity | Manufacturer COA |
| Ionic character | Non-ionic | Manufacturer COA |
| Residue coarser than 2000 µm | None | Manufacturer COA |
Ironstone does not operate a laboratory. Every figure in this table comes from the manufacturer’s certificate of analysis or data sheet, and the certificate for your batch states the exact figures. Independent testing or inspection before loading can be arranged on request.
Dosage is set by pilot test against your filtrate target in the brine you actually run — starch that performs in fresh water can behave differently in saturated salt, so test in your worst-case brine. We include the technical data sheet with dosage guidance and the temperature rating when we quote.
We quote rather than publish a list price. Polymer and freight prices both move, so a published number is out of date before you read it. Send your volume, your grade and your delivery port by WhatsApp or email. We reply within one working day, and we hold the price we quote for seven days against that volume and that port.
What we take responsibility for.Our purchase order states the specification on this page, not the supplier’s typical values. Before we release payment to the factory we require a certificate of analysis for your batch, and that certificate must include the starch test result. If it fails the specification we reject the batch: that is our problem, not yours. Independent inspection before loading is available on request, at cost.