Drilling mud — a mixture of water and bentonite clay (usually) we use to advance a borehole into the subsurface. When planning a project, drillers normally have some idea about the type of mud and additives they will use, and it usually includes bentonite, soda ash and water. There are many additives for so many different purposes that it can be overwhelming, but these additives are often necessary to successfully complete the bore. We have additives to control fluid loss, inhibit swelling clays, add extra viscosity, enhance gel strength and so on. We can add polymers or even drill the borehole with bio-polymer (non-clay) drilling fluids.
Years ago, when drilling wells, the standard procedure was to dig an earthen pit for containment of the drilling fluids. At the end of the project, we spread the excess fluids and cuttings on the project site and backfilled the pit. It was easy to see where the drilling mud was spread because the grass/plants seemed to be greener. Times have certainly changed, and the option to dig an earthen pit and spread the cuttings and excess mud on the ground surface is over. Most drillers now utilize above ground drilling fluid cleaning and recirculating/recycling systems. This leads to complications on the site; for example, how do we contain and dispose of the drill cuttings and fluids?