Drilling an Oil Well - Boring by Turbine. Liquid mud is pumped at high pressure through a non-revolving pipe to a 'turbo' drill (shown in the inset enlargement) at the bottom of the well. The casing of the 'turbo' which is fixed to the pipe and therefore cannot revolve, contains a small turbine. As the mud flows through the turbine it makes it turn. The turbine's shaft is connected with the drill through gearing, so the drill also is rotated. Having done its work, the mud escapes at the bottom of the casing and flows back to the surface outside the pipe.