Fluid is used in drilling process. That is very important for drilling rigs.
The makeup of the drilling fluid is very dependent on the formation in which you are operating, just likewater well drilling. As in water well drilling, the primary purpose of the mud program is three-fold:
• Lubricate and cool the bit.
• Return the cuttings to surface.
• Condition the borehole for stability and water loss.
Drilling fluid does not contaminate the sample from a mineralogical perspective and therefore does not affect the purity of the sample. Drilling with straight water is not advisable; only in rare cases can and/or should you drill with only water, especially in the western U.S.