Abstract: A foamable drilling fluid for use in well operations such as deep water offshore drilling where risers are not employed in returning the fluid to the surface mud pit. A preferred foamable drilling fluid comprises a prehydrated clay such as bentonite, sea water, a surfactant selected from the group consisting of .alpha.-olefinsulfonates, alkylpolyglycosides, alcohol sulfates, salts of ethoxylated alcohol sulfates, and a stabilizing surfactant consisting of cocoamine betaine. The stabilized foam drilling fluid resists foam breakdown upon drilling cessation, prevents fluid loss to reduce filter cake buildup and increases the carrying capacity of cuttings and other solids. In addition, a foamable drilling fluid is provided including an hydraulic material selected from the group consisting of Portland cement, siliceous material like fumed silica, blast furnace slag and pozzolans such as fly ash.

Abstract: The present invention provides resilient cement compositions and methods which are particularly useful in the construction and repair of oil and gas wells. The cement compositions have improved mechanical properties including elasticity and ductility and are basically comprised of cementitious material, an aqueous rubber latex and a latex stabilizer.

Abstract: A foamable drilling fluid for use in well operations such as deep water offshore drilling where risers are not employed in returning the fluid to the surface mud pit. A preferred foamable drilling fluid comprises a prehydrated clay such as bentonite, sea water, a surfactant selected from the group consisting of .alpha.-olefinsulfonates, alkylpolyglycosides, alcohol sulfates, salts of ethoxylated alcohol sulfates, and a stabilizing surfactant consisting of cocoamine betaine. The stabilized foam drilling fluid resists foam breakdown upon drilling cessation, prevents fluid loss to reduce filter cake buildup and increases the carrying capacity of cuttings and other solids. In addition, a foamable drilling fluid is provided including an hydraulic material selected from the group consisting of Portland cement, siliceous material like fumed silica, blast furnace slag and pozzolans such as fly ash.

Abstract: The present invention provides lightweight, fast setting cement compositions and methods which can be utilized in performing a variety of well cementing operations. The cement compositions are basically comprised of slag cement, water sufficient to form a pumpable slurry, a gas sufficient to foam the slurry and a foaming agent.

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 resilient cement compositions and methods which are particularly useful in the construction and repair of oil and gas wells. The cement compositions have improved mechanical properties including elasticity and ductility and are basically comprised of cementitious material, an aqueous rubber latex and a latex stabilizer.

Abstract: The present invention provides lightweight, fast setting cement compositions and methods which can be utilized in performing a variety of well cementing operations. The cement compositions are basically comprised of slag cement, water sufficient to form a pumpable slurry, a gas sufficient to foam the slurry and a foaming agent.

Abstract: Hydrocarbon base drilling fluids which are selectively convertible to cementitious compositions that set into hard substantially impermeable masses and methods of using such drilling fluids are provided. The drilling fluids are basically comprised of a hydrocarbon liquid having particulate hydraulic cement suspended therein. The drilling fluids are converted to cementitious compositions by admixing water and a surfactant therewith.

Abstract: The present invention provides well cementing methods and compositions for use in cold environments which are particularly suitable for cementing conductor strings in deep water offshore wells. The cement compositions are basically comprised of a relatively coarse particulate hydraulic cement mixed with an ultra fine particulate hydraulic cement, sufficient water to form a pumpable slurry and a fluid loss control additive.

Abstract: The present invention provides improved cementitious compositions which can include drilling fluid as a component thereof and methods of cementing wells utilizing such compositions. The compositions are basically comprised of a cementitious material, water, a hardenable resinous material and optionally, drilling fluid in an amount up to about 70% by volume of the cementitious material in the composition.

Abstract: The present invention provides improved cementitious compositions which can include drilling fluid as a component thereof and methods of cementing wells utilizing such compositions. The compositions are basically comprised of a cementitious material, water, a hardenable resinous material and optionally, drilling fluid in an amount up to about 70% by volume of the cementitious material in the composition.

Abstract: Improved hydraulic cement compositions and methods for cementing wells drilled through low temperature earth formations wherein the cement is subjected to freeze-thaw cycling are provided. The compositions are comprised of a hydraulic cement, gypsum cement, fly ash, an alkali metal halide, water, and an alcohol freezing point depressant.

Abstract: Improved well drilling fluids and methods which prevent damage to water sensitive formations while drilling are provided. The drilling fluids include a formation stabilizing compound which contains an organic quaternary ammonium cation and an inorganic, organic or combination anion.

Abstract: Improved hydraulic cement compositions and methods for cementing wells drilled through low temperature earth formations wherein the cement is subjected to freeze-thaw cycling are provided. The compositions are comprised of a hydraulic cement, gypsum cement, fly ash, an alkali metal halide, water, and an alcohol freezing point depressant.

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: Low density well cement compositions which set into hard substantially impermeable masses, but which are removable by dissolution in acid, and methods of utilizing such compositions for forming removable cement plugs or seals in subterranean zones are provided. The compositions are comprised of pumpable foamed slurries of magnesium oxychloride cement.

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: Retarded acid soluble well cement compositions which set into hard substantially impermeable masses and methods of using such compositions for forming removable cement plugs or seals in subterranean zones are provided. The compositions are comprised of magnesium oxychloride cement and a set retarder comprised of a water soluble borate and a sugar.

Abstract: Improved set retarded cement compositions and methods of using such compositions which are substantially non-thinning at high temperatures and which can include fresh or salt water are provided. The compositions are comprised of hydraulic cement, sufficient water to form a pumpable slurry, a set retarder and a delayed viscosifying agent which yields viscosity at high temperatures comprised of a treated depolymerized galactomannan gum.

Abstract: Retarded acid soluble well cement compositions which set into hard substantially impermeable masses and methods of using such compositions for forming removable cement plugs or seals in subterranean zones are provided. The compositions are comprised of magnesium oxychloride cement and a set retarder comprised of a water soluble borate and a sugar.