Chapter 4. Lubricants
One of the greatest challenges in the formulation of specialty lubricants for drilling applications is the prevention of drill bit bearing wear in subterranean formations. In such applications, lubrication takes place in an abrasive environment of mud and rock particles deep below the earth's surface.
The journal bearings are subject to extremely high loads, because the bit generally turns at slow speeds and has the weight of the drill string on top of it. Furthermore, there is shock loading due to the bouncing and vibrating of the drill string (Willey et al., 2007
There are monographs on the issues of synthetic greases, including their application in petroleum industries (Rudnick, 2006
). Synthetic greases ...