Abstract: A cementitious slurry is produced by combining an aqueous drilling fluid with a slurry of Portland cement in oil. Generally the drilling fluid is an aqueous drilling fluid containing clay such as prehydrated bentonite. The resulting composition has a particular utility in primary cementing operations for oil wells.

Abstract: A drilling and cementing process wherein a drilling fluid containing a proton acceptor metal compound component is utilized and thereafter combined with a water-soluble monomer having polymerizable unsaturated groups to give a cementitious slurry which is thereafter used in a wellbore cementing operation. There is thus provided a cementitious slurry comprising a drilling fluid, i.e., at least water and drill solids, proton acceptor metal compound component and water-soluble monomeric component having polymerizable unsaturated groups.

Abstract: A drilling and cementing operation is carried out utilizing a universal fluid comprising blast furnace slag, water, a silicate and a retarder, the components of the drilling fluid being chosen so as to have a dual functionality in promoting the drilling fluid and thereafter in being functional constituents of a cementitious slurry.

Abstract: A drilling and cementing operation is carried out utilizing a universal fluid comprising blast furnace slag, water and a polyalcohol, the components of the drilling fluid being chosen so as to have a dual functionality in promoting the drilling fluid and thereafter in being functional constituents of a cementitious slurry.

Abstract: A wellbore is drilled utilizing an oil-in-water emulsion drilling fluid, optionally containing blast furnace slag. A compatible cementitious slurry containing blast furnace slag and an activator system is then introduced into the borehole and displaced up into an annulus. Generally, the cementitious slurry is prepared by adding additional blast furnace slag and an activator such as a sodium hydroxide/sodium carbonate mixture to the used drilling fluid.

Abstract: A composition suitable for drilling and cementing comprising blast furnace slag, water, a soluble polyalcohol and an insoluble polyalcohol, the components of the drilling fluid being chosen so as to have a dual functionality in promoting the drilling fluid and thereafter in being functional constituents of a cementitious slurry.

Abstract: A slim hole well is drilled using a drilling fluid comprising blast furnace slag and water which drilling fluid is circulated during the drilling to lay down a filter cake. Thereafter, an activator is added and generally, an alkaline material and additional blast furnace slag, to produce a cementitious slurry which is passed down a casing and up into an annulus to effect primary cementing.

Abstract: A cement anchor is provided for test tools in a well in a soft or weak formation below a zone to be tested.

Abstract: An extended reach well such as the deviated wells typically drilled from offshore platforms is drilled using a drilling fluid comprising blast furnace slag and water which drilling fluid is circulated during the drilling to lay down a filter cake. Thereafter, an activator is added and generally, an alkaline material and additional blast furnace slag, to produce a cementitious slurry which is passed down a casing and up into an annulus to effect primary cementing.

Abstract: A method for preventing zonal communication or migration of fluids, in a well to be abandoned, by placement of cement plugs.

Abstract: A composition suitable for drilling and cementing comprising coal slag, water and drill solids, the components of the drilling fluid being chosen so as to have a dual functionality in promoting the drilling fluid and thereafter in being functional constituents of a cementitious slurry. Also, a method for drilling using a drilling fluid containing coal slag so as to lay down a filter cake which is settable and which is compatible with a subsequent coal slag cementitious slurry.

Abstract: A method of cementing a casing in a wellbore is provided wherein a cement slurry is placed in the wellbore prior to inserting the casing into the wellbore. Voids in the resultant cement caused by poor centralization are eliminated by placement of the cement in the wellbore prior to insertion of the casing.

Abstract: A cementitious slurry containing blast furnace slag and a surfactant is utilized to displace an oil based drilling fluid without causing contamination by the blast furnace slag cement. In a specific embodiment, a cementitious slurry comprising blast furnace slag, a surfactant and water is used in the cementing of an annulus surrounding a casing or liner wherein a synthetic oil-containing drilling fluid is present.

Abstract: Squeeze cementing is conducted using non-conventional cements such as blast furnace slag--water base drilling fluid mixtures which are not adversely affected by brine or pockets of gelled drilling fluid beneath the primary cement.

Abstract: During directional drilling operation, in order to achieve the correct angle and direction when drilling through a soft formation, a plug of a non-conventional cement is set across the zone in order to achieve the desired course and target. The non-conventional cement is preferably blast furnace slag and a water base drilling fluid.

Abstract: A drilling fluid is diluted and a cementitious component added thereto. In a more specific embodiment the dilution is carried out by introducing liquid such as water to a flowing stream of the drilling fluid and thereafter a cementitious component is mixed therewith. Thus, the drilling fluid can be used in a conventional manner to drill a well and thereafter diluted and a cementitious component added to produce a cement for cementing operations such as setting a casing in the well and/or can be used for remedial cementing.In another embodiment of the invention, the drilling fluid itself contains a small amount of cementitious component and additional cementitious component is added after the dilution.

Abstract: A cementitious slurry comprising microfine ground blast furnace slag and normally ground blast furnace slag. A microfine ground blast furnace slag is made of composition having a blaine specific surface area between 8,000 and 20,000 cm.sup.2 /g. By normally ground is meant slag compositions having a surface area of less than 8,000 cm.sup.2 /g. Such cementitious compositions have utility in construction, road building, and cementing wellbores.

Abstract: A drilling and cementing process wherein a drilling fluid containing a metal compound which is a proton acceptor component is utilized, thereby laying down a filter cake. Thereafter, the drilling fluid can be combined with a phosphorus acid to give a cementitious slurry which is thereafter used in a cementing operation. Alternatively, a phosphorus acid such as polyphosphoric acid is circulated into contact with said filter cake.

Abstract: A method to cement wellbores in salt formations is provided using a cement slurry composition comprising blast furnace slag, water and salt. The salt improves compressive strength of blast furnace slag based cements. This method is useful in cementing wellbores within salt and potash formations because salt saturated cement slurries can be prepared without the need for expensive additives.

Abstract: The present invention is a method to cement a wellbore in the presence of carbon dioxide, or when the wellbore will subsequently be exposed to carbon dioxide. The wellbore is cemented using a blast furnace slag cement slurry, and the resulting set cement is considerably less susceptible to degradation by carbon dioxide.