MicroBar micronized weighting additive | SLB


Micronized weighting additive

Schlumberger Oilfield Services

MicroBar™ micronized weighting additive is a high-quality micronized barite used as a weighting agent for nonaqueous drilling fluid applications. Compared with API drilling-grade barite, the MicroBar additive reduces barite sag and settlement.

MicroBar is a mark of M-I L.L.C., an SLB company.

Enhance operational flexibility

Compatible with all base fluid types, the additive was developed as a dry, pneumatically conveyable product that can increase the mud weight of high-density nonaqueous fluids where barite sag represents a high risk.

Optimize viscosity profile

Containing barite ground to 5–8 um on average, the MicroBar additive offers an enhanced viscosity profile, especially during the prolonged static periods associated with casing and liner runs, emergency disconnects, or planned long-term logging programs.

Maintain density at ultrahigh temperatures

Notably, the MicroBar additive maintains constant density, even at bottomhole temperatures of 392 degF [200 degC]. This feature reduces the risk of well control issues and NPT associated with wide density variations.

Save rig time and logistics costs

The ultrafine MicroBar additive is pneumatically conveyable and can be blown from the vessel or bulk trailer to a tank. Pneumatic conveyance eliminates the labor-intensive handling required with micronized dry barite.

Typical Physical Properties
Physical appearance Gray to white powder
Bulk density 120–150 lbm/ft[1,920–2,400 kg/m3]
Minimum specific gravity 4.10
Particle size distribution ≤25 um


Applications where weighting agent requires lower particle size distribution.

Toxicity and handling

Normal safety protective equipment should be worn. Observe the precautions described on the safety data sheet. Dust masks should be worn while discharging MicroBar additive.

Packaging and storage

MicroBar additive is available in bulk or can be packaged in 3,300-lbm [1,500-kg] and 2,205-lbm [1,000-kg] bags. Big bag handling facilities need to be available for onsite rig use. Protect MicroBar additive from moisture.