When we want to make a hole or well, we use big machines like drills which are like giant screwdrivers. These drills need some kind of liquid to help them dig through rocks and dirt without getting stuck. This liquid is called drilling fluid or mud.
Drilling fluids are special liquids that are made up of different things, just like you might mix water, sugar, and juice to make a tasty drink. The drilling fluid has to be just the right thickness, or viscosity, so it can easily move through the rocks and dirt without causing any damage. It also has to be strong enough to push aside heavy rocks and stones in the earth.
The drilling fluid also helps to keep the drill cool by absorbing the heat created by friction from the spinning drill bit. If the drill gets too hot, it might break down, just like your toy might break if it gets too hot.
Overall, drilling fluid is like a helper for the drilling process. It keeps the drill moving smoothly, keeps it cool, and makes sure the hole is dug perfectly without any damage.