Abstract: A non-aqueous system for cleaning a section of a subterranean well bore and installing a water based fluid system into the well bore. The well bore may be an open hole or contain a casing string therein. A series of spacer fluids are introduced into the well bore to displace the drilling fluid in order to clean and water wet the section of well bore. In the preferred embodiment, three spacers are pumped into the well bore including a first spacer containing a solvent, a second spacer containing a solvent and a third spacer containing a surfactant. A water based fluid system may thereafter be introduced into the well bore. The water based fluid system will be a completion fluid in the preferred embodiment.

Abstract: Aqueous and non-aqueous systems for cleaning a section of a subterranean well borehole and casing prior to cementing. A series of spacer fluids are introduced into the borehole to displace drilling fluid and to provide clean and water wet casing and borehole surfaces of the cleaned section of well bore. The cleaned section of the well bore will provide surfaces for superior bonding of the cement to the surfaces.