Its role is mainly to seal well walls and lubricate the drill head during drilling operations.
Bentonite is a mineral composed of 60 to 80% of montmorillonite. Bentonite has a high swelling property and when combined with water, it shows a thixotropic state, ie by removing the external shear stress, its viscosity returns to the previous state. Bentonite is most used in well drilling industries because drilling bentonite is able to cover the walls of oil wells as well as water wells and by reducing swelling and hardening, reduces the effect of any stress and pressure on the walls to prevent the well from falling. Of course, bentonite also has other advantages in drilling, such as acting as a flushing material and helping to drain oil and gas more easily by increasing the volume of well fluid. It also protects them from erosion by cooling drills and drilling and cutting tools. When the discharge pumps are stopped, the thixotropic property of drilling bentonite mud prevents rocks from falling into the well and damages the main drilling shaft.
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