Abstract: A method of and product for use in cementing the annulus of a hydrocarbon well having a casing centered within a hole bored from a surface. The method comprises the steps of introducing an effective amount of colouring agent contained in a water-soluble bag into a portion of spacer or scavenging fluid, pumping the spacer or scavenger and a then cementing slurry down the casing to the bottom of the hole to displace drilling mud upwardly through the annulus to the surface, until the colouring agent becomes visible at the surface, displacing the casing volume and then stopping the pumping and allowing the pumped cement slurry to harden.

Abstract: Calcium oxide (C.sub.a O--Hot Lime--Processed Lime) is added to a Hydrocarbon Based Fluid (Crude Oil--Refined Oil--Diesel Fuel--Mineral Oil--etc.) used as a drilling fluid to drill bore holes (Oil and Gas Wells--Mine Shafts--etc.) to react with any water (H.sub.2 O) present to generate a water free fluid. Several advantages result from accomplishing the water removal process including higher drilling rates, lower fluid preparation and maintenance costs, lower drilling fluid pumping costs, improved solids removal from the drilling fluid at the surface, improved bore hole conditions and improved environmental cleanup of the drill solids waste.