A method of designing a cement slurry comprising: (a) selecting at least a cement and concentration thereof, a water and concentration thereof, and one or more chemical additives concentration thereof such that a cement slurry formed from the cement, one or more chemical additives, and the water meet a density requirement; (b) calculating a thickening time of the cement slurry at the wellbore temperature using a thickening time model; (c) comparing the thickening time of the cement slurry to a thickening time requirement and performing steps (a)-(c) if the thickening time of the cement slurry does not meet or exceed the thickening time requirement, wherein the step of selecting comprises selecting different concentrations and/or different chemical identities for the cement and/or one or the more chemical additives than previously selected, or performing step (d) if the thickening time of the cement slurry meets or exceeds the thickening time requirement; and (d) preparing the cement slurry.

A method may include: defining engineering parameter of a proposed cement slurry, the engineering parameters comprising at least a compressive strength requirement, a density requirement, a storage time requirement, and a thickening time requirement; selecting, based at least in part on a model of compressive strength, a model of storage time, and the density requirement, at least a cement and mass fraction thereof, at least one supplementary cementitious material and mass fraction thereof, and a water and mass fraction thereof, such that a cement slurry formed from the cement, the at least one supplementary cementitious material, and the water meets the compressive strength requirement and the density requirement; selecting, based at least in part on a model of thickening time, an accelerator and mass fraction thereof; selecting, based at least in part on a model of activator thickening time, an activator and mass fraction thereof; and preparing a cement slurry comprising the cement and mass fraction thereof, the at least one supplementary cementitious material and mass fraction thereof, the water and mass fraction thereof, and the cement retarder and mass fraction thereof.

A method may include: defining engineering parameter of a proposed cement slurry, the engineering parameters comprising at least a compressive strength requirement, a density requirement, a storage time requirement, and a thickening time requirement; selecting, based at least in part on a model of compressive strength, a model of storage time, and the density requirement, at least a cement and mass fraction thereof, at least one supplementary cementitious material and mass fraction thereof, and a water and mass fraction thereof, such that a cement slurry formed from the cement, the at least one supplementary cementitious material, and the water meets the compressive strength requirement and the density requirement; selecting, based at least in part on a model of thickening time, an accelerator and mass fraction thereof; selecting, based at least in part on a model of activator thickening time, an activator and mass fraction thereof; and preparing a cement slurry comprising the cement and mass fraction thereof, the at least one supplementary cementitious material and mass fraction thereof, the water and mass fraction thereof, and the cement retarder and mass fraction thereof.

It has been unexpectedly discovered that the addition of a natural or other pozzolan to non-spec fly ash significantly improves the properties of the non-spec fly ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C fly ash. The natural pozzolan may be a volcanic ejecta, such as pumice or perlite. Other pozzolans may also be used for this beneficiation process. Many pozzolans are experimentally tested and may be used to beneficiate non-spec fly ash into certifiable Class F fly ash. Additionally, this disclosure provides a method of converting a Class C fly ash to a more valuable Class F fly ash. This discovery will extend diminishing Class F fly ash supplies and turn non-spec fly ash waste streams into valuable, certified fly ash pozzolan which will protect and enhance concrete, mortars and grouts.

A geopolymer cementing fluid with controllable thickening time includes the following components in parts by weight: 100 parts of a cementitious material, 10 parts-30 parts of an activator, 0.2 parts-5 parts of a retarder, 0.4 parts-4 parts of an anti-settling agent, and 30 parts-70 parts of water. The geopolymer cementing fluid of the present invention has the advantages of controllable thickening time, excellent compressive strength, good settlement stability, good rheological properties, green and eco-friendly, and the like. The geopolymer cementing fluid can be better suited for the operations of oil and gas well cementing and ensure cementing safety.

A geopolymer cementing fluid with controllable thickening time includes the following components in parts by weight: 100 parts of a cementitious material, 10 parts-30 parts of an activator, 0.2 parts-5 parts of a retarder, 0.4 parts-4 parts of an anti-settling agent, and 30 parts-70 parts of water. The geopolymer cementing fluid of the present invention has the advantages of controllable thickening time, excellent compressive strength, good settlement stability, good rheological properties, green and eco-friendly, and the like. The geopolymer cementing fluid can be better suited for the operations of oil and gas well cementing and ensure cementing safety.

A low density annular grout composition for filling voids. The composition may consist of cementitious fly ash, water, set retarder and cellular foam. The composition may have a compressive strength of between 100 and 600 psi at seven days and less than 1500 psi at 28 days. The composition may have a density between 20 and 75 pcf. Also disclosed is a method of filling a void with a low density annular grout composition. The method can include determining the time necessary to fill the void, adding water and set retarder to a cementitious fly ash to make a wet mixture, adding air to the wet mixture, and adding the composition to the void.

A low density annular grout composition for filling voids. The composition may consist of cementitious fly ash, water, set retarder and cellular foam. The composition may have a compressive strength of between 100 and 600 psi at seven days and less than 1500 psi at 28 days. The composition may have a density between 20 and 75 pcf. Also disclosed is a method of filling a void with a low density annular grout composition. The method can include determining the time necessary to fill the void, adding water and set retarder to a cementitious fly ash to make a wet mixture, adding air to the wet mixture, and adding the composition to the void.

Method of efficiently manufacturing cement-SCM compositions having improved strength compared to cement-SCM compositions made using conventional methods. The cement-SCM compositions may contain: (A) a fine interground particulate component with (1) a hydraulic cement fraction and (2) a supplementary cementitious material (SCM) fraction; (B) a coarse particulate component comprised of coarse SCM particles not interground with the fine interground particulate component; and optionally (C) an auxiliary particulate component not interground with the fine interground particulate component or the coarse particulate component. A method of manufacturing a cement-SCM composition may be performed by: (A) intergrinding hydraulic cement (e.g., cement clinker) with one or more SCMs to form a fine interground particulate component; (B) blending, without intergrinding, the fine interground particulate component with a coarse particulate component comprised of coarse SCM particles; and optionally (C) further combining, without intergrinding, an auxiliary particulate component with the fine interground particulate component and the coarse particulate component.

Method of efficiently manufacturing cement-SCM compositions having improved strength compared to cement-SCM compositions made using conventional methods. The cement-SCM compositions may contain: (A) a fine interground particulate component with (1) a hydraulic cement fraction and (2) a supplementary cementitious material (SCM) fraction; (B) a coarse particulate component comprised of coarse SCM particles not interground with the fine interground particulate component; and optionally (C) an auxiliary particulate component not interground with the fine interground particulate component or the coarse particulate component. A method of manufacturing a cement-SCM composition may be performed by: (A) intergrinding hydraulic cement (e.g., cement clinker) with one or more SCMs to form a fine interground particulate component; (B) blending, without intergrinding, the fine interground particulate component with a coarse particulate component comprised of coarse SCM particles; and optionally (C) further combining, without intergrinding, an auxiliary particulate component with the fine interground particulate component and the coarse particulate component.