What Mud Fluid in drilling for ?

The drilling mud are primarily for:

1. to lubricate and cool the drill drilling that would otherwise warming, for the friction with the rock , quickly arrive at break.
2. Pipe on the surface of earth and rock fragments (commonly known by the English technical term for cutting ) produced by the action of the chisel.
3. Exercise a counter pressure hydrostatic hole at the bottom and along its walls discoveries (ie not tubate) to contain the leakage of the fluid layer and to avoid the risk of kick or in more severe cases the real eruption of the well.
4. Supporting walls of the hole (thanks to the pressure exerted by the hydrostatic load), in order to prevent landslides and loss of the punched hole. This feature is said that the mud must do "panel" that must practically "plaster" the walls of the well.
5. The most important properties of the drilling mud must be the "thixotropy", namely the characteristic that, at the time that the circulation in the pit stops, the sludge to be gelled fluid holding imprisoned in suspension the cutting resulting from the drilling. Otherwise these debris, stopping the circulation of the fluid, would fall to the bottom hole imprisoning the chisel and the "battery terminal part" drilling.

In the oil exploration monitoring geological of drilling muds, by analyzing the microscope of fragments of rock it allows to recognize the stratigraphy of the perforated rocky succession and provides the first indications of the characteristics petrophysical properties of the reservoir . 

Furthermore, the analysis by means of gas chromatographs , of the fluids contained in the outgoing mud from the well, provides important clues for the detection and recognition of mineralized levels to hydrocarbons.

In some cases similar muds are used temporarily to support the walls of trenches or over works of excavation of civil engineering within loose soil, prior to the implementation of their final completion.