What is a significant role of the drilling fluid besides cooling the drill bit?

The primary function of drilling fluid, also known as mud, is to maintain pressure in the borehole. This is crucial for preventing the collapse of the borehole walls and for managing formation pressures. By exerting hydrostatic pressure, drilling fluid counteracts the pressure exerted by the surrounding rock formations and fluids. This pressure balance helps to stabilize the wellbore and prevents issues such as blowouts, which can occur if the pressure is too low.

Maintaining pressure is also essential during the drilling process because it helps to keep unwanted fluids from entering the borehole, which could lead to contamination or other drilling complications. Thus, the role of drilling fluid in maintaining borehole pressure is critical to ensuring a safe and efficient drilling operation while also protecting the integrity of the surrounding environment.