Abstract: The present invention provides cementitious well drilling fluids and methods of drilling subterranean well bores. The drilling fluids are basically comprised of water, a water viscosity increasing material and a cementitious material which when deposited on the walls of the well bore as a part of the filter cake thereon consolidates the filter cake into a stable mass that readily bonds to a cementitious material slurry subsequently placed in the well bore. The methods of drilling a subterranean well bore are basically comprised of the steps of preparing a drilling fluid of the invention and drilling a subterranean well bore using the drilling fluid.

Abstract: The present invention provides methods of cementing a well with a cementing composition utilizing a portion of the fluid used to drill the well as a component of the cementing composition. The methods basically comprise forming a cementing composition, consisting essentially of a cementing precursor composition and a set-activator introducing the cementing composition into the well and permitting the cementing composition to set into a hard mass therein; wherein the cementing precursor composition is the fluid used to drill the well.

Abstract: The present invention provides fly ash cementing compositions and methods which are useful in any cementing application, and are particularly suitable for cementing in subterranean zones penetrated by well bores. The cementing compositions can include a portion of the drilling fluid used to drill a well bore as a component thereof. Also, drilling fluid can be disposed of by combining it with the fly ash cementing composition whereby it solidifies in a disposal location.

Abstract: The present invention provides methods of cementing a well with a cementing composition utilizing a portion of the drilling fluid used to drill the well as a component of the cementing composition. The methods basically comprise forming a cementing composition, consisting essentially of a cementing precursor composition, a set-activator, and a portion of the drilling fluid, introducing the cementing composition into the well and permitting the cementing composition to set into a hard mass therein.

Abstract: Set-activated cementitious compositions and methods of using such compositions in cementing subterranean zones penetrated by well bores are provided. The compositions are basically comprised of water, particulate condensed silica fume suspended in the water; a dispersing agent for facilitating the dispersal of the silica fume particles in the water and maintaining the particles in suspension therein, a set-activator and a set delaying additive for increasing the time in which the composition sets after the set-activator is combined therewith.

Abstract: The present invention provides methods of cementing a well with a cementing composition utilizing a portion of the drilling fluid used to drill the well as a component in the cementing composition. The methods basically comprise forming a set-activated cementing composition comprised of water, silica fume, a dispersing agent, a set-activator, a set delaying additive and a portion of the drilling fluid, introducing the resulting set-activated cementing composition into the well and permitting the cementing composition to set into a hard mass therein.

Abstract: Methods of drilling a well bore utilizing a circulating drilling fluid and subsequently disposing of the drilling fluid by converting it to a cementitious composition are provided. The methods basically comprise the steps of forming the drilling fluid with an aqueous suspension of condensed silica fume as a component thereof, drilling a well bore using the drilling fluid, activating the drilling fluid whereby it will subsequently set into a hard cementitious mass and placing the set activated drilling fluid in one or more desired locations whereby it sets therein.

Abstract: A gelable silicate solution prepared by mixing fumed silica and an alkali metal hydroxide with water is provided. The silicate solution is used to form a seal or plug in one or more subterranean formations or in a well bore penetrating the formations by pumping the solution into a desired location in the well bore or formations and allowing the silicate solution to gel therein.

Abstract: Set retarded cement compositions for cementing across a zone or zones in a well having enhanced compressive strength and rapid gel strength development after placement. The cement compositions are comprised of hydraulic cement, sufficient fresh water to form a pumpable slurry, a set retarder comprising a copolymer of 2-acrylamido, 2-methylpropane sulfonic acid and acrylic acid having a average molecular weight below about 5000 and any other desired additives. Methods of cementing utilizing the cement composition also are provided.

Abstract: Set retarded cement compositions for cementing across a zone or zones in a well having enhanced compressive strength and rapid gel strength development after placement. The cement compositions are comprised of hydraulic cement, sufficient fresh water to form a pumpable slurry, a set retarder comprising a copolymer of 2-acrylamido, 2-methylpropane sulfonic acid and acrylic acid having an average molecular weight below about 5000 and any other desired additives. Methods of cementing utilizing the cement composition also are provided.