Abstract: The thermal stability of hardened drilling mud-concrete is improved by incorporating blast furnace slag, microfine slag or fine ground glass into the mud-concrete prior to hardening.

Abstract: A high alumina wellbore cementing composition is provided, the composition comprising:a) high alumina cement; andb) a polyacrylic acid phosphinate having a molecular weight of about 3800 in an amount effective to prevent gelation of the cementing composition for a time period of at least three hours.This composition can remain pumpable for a time period sufficiently long to place the cement in a wellbore using conventional wellbore cementing procedures, and, after the composition is cured, is capable of withstanding elevated wellbore temperatures.

Abstract: A water-in-oil emulsion drilling fluid can be converted into an oil mud-cement slurry for use in oil well cementing procedures. Also, a universal fluid can be prepared using the water-in-oil emulsion drilling fluid by treating with an hydraulic material so that it will lay down a filter cake during drilling which can be triggered to set into a hard cement and bond to the formation after the above oil mud-cement slurry has been placed in the borehole at the conclusion of drilling.

Abstract: A universal fluid which includes a water-based drilling mud and a hydraulic material is used to drill a borehole and lay down settable filter cake. After drilling is completed, the filter cake and universal fluid are caused to solidify in selected parts of the borehole by admixing the universal fluid with an activator.

Abstract: A water-in-oil emulsion drilling fluid can be converted into an oil mud-cement slurry for use in oil well cementing procedures. Also, a universal fluid can be prepared using the water-in-oil emulsion drilling fluid by treating with an hydraulic material so that it will lay down a filter cake during drilling which can be triggered to set into a hard cement and bond to the formation after the above oil mud-cement slurry has been placed in the borehole at the conclusion of drilling.

Abstract: A casing or liner in a wellbore penetrating a zone having high formation gas pressure is cemented with a cementitious slurry comprising blast furnace slag. In one embodiment the cementitious slurry is made by combining blast furnace slag and a drilling fluid. Also, a method for plugging or setting sidetracking plugs and other secondary cementing operations in a wellbore penetrating a zone having high gas formation pressure comprising placing a mass of blast furnace slag cementitious slurry at a preselected location and allowing the slurry to set.

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 wellbore is drilled utilizing a conventional drilling fluid or a drilling fluid such as one containing a cementitious component selected from blast furnace slag, a metal oxide component of an ionomer or a metal oxide component of a phosphate salt. A compatible cementitious slurry such as one containing blast furnace slag and an activator system is then introduced into the borehole and displaced up into an annulus by direct contact with a displacement fluid. Generally, in the case of the slag-containing drilling fluid 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. Similarly, in the case of the ionomers or phosphates, additional metal oxide component and the reactive second component can be added to the used drilling fluid to produce the cementitious slurry.

Abstract: A spacer fluid containing blast furnace slag is utilized in a well drilling operation. In one embodiment an oil emulsion drilling fluid is displaced using spacer fluid comprising water, blast furnace slag and a surfactant. In another embodiment a spacer fluid comprising blast furnace slag and water is used in the cementing of an annulus surrounding a pipe with a blast furnace 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: A spacer fluid containing blast furnace slag is utilized in a well drilling operation. In one embodiment an oil emulsion drilling fluid is displaced using spacer fluid comprising water, blast furnace slag and a surfactant. In another embodiment a spacer fluid comprising blast furnace slag and water is used in the cementing of an annulus surrounding a pipe with a blast furnace slag cementitious slurry.

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: 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 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: A method for consolidating incompetent formations penetrated by a borehole using drilling fluids. The method uses a water-based drilling fluid the solids contents of which includes microfine-ground blast furnace slag. This provides a fluid that will penetrate the incompetent formation and harden in place to consolidate the formation. Subsequent cementing with a cementitious slurry comprising water, activator and normally-ground blast furnace slag results in a compatible cement which will adhere to filter cake from the drilling.

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.

Abstract: In a drilling and cementing operation utilizing a lead cementitious slurry made from blast furnace slag and drilling fluid, a lower density transition fluid is utilized between said lead cementitious slurry and a tail Portland cement slurry. In one embodiment, the lead cementitious slurry and the transition fluid slurry are made by introducing blast furnace slag into a flowing stream of drilling fluid.

Abstract: Drilled cuttings are disposed of by solidification by drilling with a drilling fluid containing blast furnace slag, thereby producing drilled cuttings and other solid wastes, concentrating the wastes and then solidifying the concentrated wastes. Drilling wastes solidified by blast furnace slag are hard and unleachable and the blast furnace slag is compatible with both oil and water based drilling muds and drilled cuttings. Drilling fluids therefore do not have to be removed from the drilled cuttings prior to solidification in a mud pit.

Abstract: A method for installing piles in offshore waters using a drill and grout technique. The method utilizes a drilling fluid for drilling the borehole for the pile that forms a cementitious filter cake on the borehole wall and a cement for grouting the pile that is compatible with both the filter cake and salt water.