Glorious mud

'Mud, Mud, glorious mud
Nothing quite like it for cooling the blood!
So follow me, follow
Down to the hollow
And there let us wallow
In glorious mud'

Chorus lyrics from The Hippopotamus by Flanders and Swann

Another early morning visit to Aberdeen, and another chance to wander around the harbour. These are storage tanks for the drilling mud used by the North Sea oil exploration companies. Drilling mud is a very different kettle of fish to the glorious mud much beloved by hippopotami.

Drilling mud, also known as drilling fluid, is a product which is used in the process of drilling deep boreholes. One of the most critical roles of drilling mud is as a lubricant. Drilling generates tremendous friction, which can damage the drill or the formation being drilled. Drilling mud cuts down on the friction, lowering the heat of drilling and reducing the risk of friction-related complications. The mud also acts as a carrier for the materials being drilled, with material becoming suspended in the mud and then being carried up the drill to the surface. Different muds are needed for different circumstances, and the selection and formulation of mud is managed by a mud engineer. This engineer determines the correct viscosity level for the drilling mud, and adjusts factors such as density of the mud as well.