(under subclass 65) Processes comprising the step of subjecting drilling fluid which has been returned to the surface of the earth from the borehole to a physical or chemical treatment at the surface.
(1) Note. The treatment at the surface must include more than the mere addition of a material which is to be effective down the borehole, such as adding material to a gaseous drilling fluid to prevent wetting of cuttings or to a liquid drilling fluid to prevent lost circulation, see subclasses 68 and 72, respectively.
SEE OR SEARCH THIS CLASS, SUBCLASS:
88, for vehicle or conveyor for carrying cuttings laterally of bore axis.
206+, for apparatus for treating drilling fluid.
207+, for apparatus for cuttings or flushing fluid handling means at the bore entrance including chutes, etc.
