Drilling starch for high-temperature wells: what buyers should check

Fluid loss is one of the first problems a mud engineer has to control. When the liquid phase of a water-based drilling fluid seeps into the formation, it leaves behind a thick filter cake, destabilises the borehole and can damage the productive zone. Modified drilling starch is one of the most widely used and cost-effective additives for keeping that filtrate under control.

What drilling starch does in the mud

Drilling starch is a chemically modified starch that swells in water and plugs the fine pores of the filter cake. The result is a thinner, tighter cake and a lower filtration rate. A good grade does this without adding much viscosity, so the mud stays pumpable and the engineer keeps control of rheology separately.

In practice, a well-chosen drilling starch helps to:

• lower the API fluid loss of water-based muds,
• improve borehole stability, especially in reactive shales,
• work in fresh water as well as in saturated salt systems,
• flocculate dispersed cuttings when drilling with clear water.

HT and LT grades: why temperature matters

Ordinary starch begins to break down as bottom-hole temperature rises, and its fluid-loss control falls away. That is why suppliers offer two families:

• LT (low-temperature) drilling starch for shallower, cooler sections.
• HT (high-temperature) drilling starch, modified to keep working after prolonged exposure to heat. Performance is normally proven by hot-rolling the mud at 140 °C before testing.

If your wells are deep or hot, ask specifically for HT data measured after hot rolling, not before.

Five specifications to confirm before you order

1. Moisture – typically around 10%. Higher moisture means you pay for water and risk caking in storage.
2. API fluid loss after hot rolling – in both fresh (well-site) water and saturated salt water. For an HT grade, look for results of about ≤ 12 ml.
3. Viscometer reading at 600 rpm – confirms the starch is not thickening the mud more than expected (for example ≤ 18 after hot rolling).
4. pH of the test mud – usually in the 7–8 range.
5. Appearance and solubility – an off-white to white free-flowing powder that disperses without lumps.

Always ask for a Certificate of Analysis (COA) for the actual batch being shipped, not a generic data sheet.

Approvals, packing and documents

Many national oil companies and service contractors buy only from approved sources. Brij Impex's drilling starch carries Saudi ARAMCO approval, which is often the shortest route through a buyer's qualification process.

For export orders, also confirm the packing (multi-wall paper or PP bags with liner, palletised and shrink-wrapped), the shelf life, and the shipping documents: COA, MSDS/SDS, Certificate of Origin, packing list and bill of lading. Independent inspection by SGS, Intertek or Bureau Veritas can be arranged before loading.

How we can help

Brij Impex has been supplying industrial chemicals internationally since 2002, including drilling starch and other oilfield chemicals. We can share the full specification, a batch COA and a sample for your laboratory, and quote FOB or CIF to your port. See the Drilling Starch HT product page or use the enquiry form below.