Bentonite is a type of absorbent clay that primarily consists of montmorillonite, a mineral that forms through the weathering of volcanic ash. It is widely used in the oil and gas industry, particularly in the formulation of drilling fluids (muds) for wellbore stability, mud cake formation, and controlling filtration. Bentonite's high swelling and gelling properties make it an essential component of drilling muds, where it helps to maintain proper viscosity, control fluid loss, and improve the lubrication of drill bits.

Additionally, bentonite has various industrial applications such as in foundries, construction, and as a binder in pelletizing iron ore.

Application:

• Drilling Fluids: Used to thicken the mud and help suspend solids in drilling operations.
• Mud Rheology Control: Increases the viscosity of drilling fluids to optimize flow and prevent sagging.
• Fluid Loss Control: Forms a thin, impermeable filter cake on the wellbore wall, reducing the loss of fluid into porous formations.
• Shale Stabilization: Helps prevent the destabilization of shale formations by controlling fluid loss and mitigating swelling.