Barite Sag Prevention in Drilling Fluid

Barite sag is the settling of weighting material (typically barite) out of the drilling fluid, most often seen in deviated, high-angle, and horizontal wells, and during periods of low circulation or static conditions. It can cause density variation across the wellbore and downhole pressure-control issues. Organoclay is used to build low-shear-rate viscosity and gel structure that help keep weighting material suspended and reduce sag risk.

Deviated and high-angle wells allow weighting material to settle along the low side of the wellbore more easily than in vertical sections, and extended static periods during connections or logging increase the risk. Elevated downhole temperature in HPHT wells can also reduce the structure a standard organoclay grade holds, which is why a high-temperature grade path is typically reviewed for these conditions.

Organoclay builds a structural network across the continuous oil phase that raises low-shear-rate viscosity and gel strength, helping the fluid carry and hold weighting material in place during low-shear and static periods. This same suspension mechanism described on the suspension and anti-settling solution page applies to sag prevention, with an added focus here on deviated-well geometry and temperature.

For high-angle, deviated, or HPHT wells with sag risk, the high-temperature organoclay path around OD-29 is typically the starting review point, since it is positioned to hold structure as downhole temperature rises. Final selection still depends on base oil, mud weight, well geometry, and temperature, so confirm with the current TDS and sag testing in your own formulation.

Sag behavior is well-formulation- and well-geometry-specific, so static and dynamic sag test results are not published on this page. Buyers should request the current TDS and run static or dynamic sag testing at their target mud weight and well angle before finalizing a formulation for a sag-prone well.