Attapulgite - (Saltgel)

Attapulgite (palygorskite) has a rod-like crystal structure. When dispersed in water — fresh or saline — these rods form a random, entangled network that provides viscosity and gel strength through physical obstruction of fluid flow. This structural mechanism is independent of ionic concentration, making attapulgite effective across the full salinity range.

Attapulgite-based drilling fluids maintain effective viscosity across the full salinity range from fresh water to near-saturated NaCl brine (~30% by weight) and seawater (3.5% NaCl). They are also effective in CaCl₂ and KCl brine systems — making them indispensable for offshore and brine-based drilling applications.

API 13A specifies performance requirements including minimum viscosity development at standard test concentration, maximum residue on 200-mesh sieve, maximum moisture content, and minimum gel strength. API-compliant grades (Micron GEL SLT – API) provide operators with guaranteed performance consistency and quality traceability.

Attapulgite is typically used at 15–30 kg/m³ (5–10 ppb) of drilling fluid to provide adequate viscosity for cuttings transport in saline environments. Higher concentrations are used for wells requiring enhanced hole cleaning in horizontal or high-angle sections.

Yes. In transition zones where salinity is increasing from fresh to saline conditions, blends of bentonite and attapulgite are used, with the attapulgite proportion increasing as salinity increases. At full seawater salinity, attapulgite completely replaces bentonite as the primary viscosifier.