Very good your contribution @tomlee, as I have always said in my publications, drilling mud is very important in drilling activities, since the mud inside the hole is like the blood that circulates through our body. It is also important to highlight reservoir pressures that are handled when drilling some wells, since if they are reservoir with low pressures, it is convenient to drill with fluids under balance, where bentonite does not help much. Greetings, I hope to be soon reading your publications about drilling fluids.