The drilling fluids that are typically mixed and designed by a mud engineer serve various functions for the trenchless installation of a main. The unique function of drilling fluid in the directional boring process is:
- To discharge and remove the soil/geological cuttings in the bore.
- To reduce the friction of the drill rods in the bore hole.
- To stabilise the hole and to reduce the likelihood of the hole caving in.
- To lubricate and smoothly embed the main whilst being pulled in.
- To protect the drill rods, drill head and reamers from abrasion and to cool the temperature during rotation.
- To loosen the soil that is around the cut area of the drill head or reamer.
- To create a filter cake wall and to protect the ground water from running.
- To run the mud motor when drilling in rock.