Since that is unlikely in the near future, the settling tank is extremely important. If the shaker screen were always adequate, never developed a tear that passed oversize solids through, never had to be bypassed during drilling, etc., the major justification for a settling tank (or “shale trap,” or “sand trap”) would disappear. Some information has been published on the subject, but the following points are cardinal:
The drilling fluid circulating system is like a close loop electric circuit through which drilling fluid (i.e. mud) can travel from surface to all the way down hole and back to its initial point (i.e. mud pit).
Mud gun are meant to provide supplemental or primary mixing in mud tanks depending on the number being used and the pit size. They are best used in tank corners to keep solids from settling and a mud agitator is placed in the tank center.
This section provides additional thoughts and considerations concerning solids-control equipment. The practical operational guidelines for equipment discussed here may not apply to all drilling applications. These guidelines (in italics) were developed as part of API RP 13C. The discussion beneath each captures some of the comments by committee members as they debated the guideline before approval.