Organo Clay

Regular bentonite is hydrophilic and only swells and develops viscosity in water. In oil-based drilling fluids, regular bentonite cannot disperse or swell, providing no rheological benefit. Organo clay's organophilic surface allows it to wet and disperse in oil, developing viscosity and gel strength in OBM systems.

Organo clay develops a gel structure (gel strength) in OBM at rest. This gel network traps and suspends barite particles, preventing them from settling downward (barite sag) during periods of low circulation or drill string rotation. Sag prevention is critical in directional and horizontal wells.

Riobent 236 OG is the standard grade for general OBM applications, providing reliable viscosity and gel strength development. Riobent 236 OGH is engineered for extreme temperature conditions (HPHT wells) where standard organo clay grades lose viscosity effectiveness, maintaining stronger gel structure above 150–180°C.

Most organo clay grades require a polar activator (typically 95% ethanol or propylene carbonate) to develop full viscosity and gel strength. The activator promotes dispersion of clay platelets. Typical activator dosage is 30–50% of the organo clay weight. Some self-activating grades are available.

Organo clay can be pre-dispersed in the base oil component of the OBM before other ingredients are added. This pre-dispersion approach maximises clay activation and ensures optimal viscosity development. Adding organo clay to a fully formulated OBM system at the rig site is also possible but may require longer mixing time.