Drilling Mud

Drilling fluid is the circulating fluid used in drilling to lubricate the bit, carry cuttings, stabilize the wellbore and balance formation pressure

Major function 

Carrying cuttings: transporting the crushed cuttings from the bottom of the well to the surface.

Cooling lubrication: reduce the temperature of the drill bit and reduce the wear of the drill.

Stabilize the wellbore: prevent the collapse of the wellbore by pressure balance.

Balance formation pressure: control the invasion of fluids downhole and avoid blowout or leakage