Drilling muds have four basic properties that determine the behavior of the mud as a drilling fluid – viscosity, density, gel strength and filtration. Several other properties, although of lesser importance, need to be checked, especially if problems are anticipated or encountered.
In normal mud rotary drilling, it is not unusual for solids content to approach 20 percent of returns during fast-hole drilling. This is good; it means fast penetration and thus, a quicker, more profitable hole. The trick is to get the solids out of the mud before it is returned to the hole.
