Development of geopolymer cements utilizing red mud for primary well cementing applications
AssigneeSaudi Arabian Oil Company
InventorsKhawlah A. Alanqari, Abdullah Al-Yami, Mohammad Alharthi
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Abstract
A composition and method for well cementing are provided. The composition comprises a geopolymer slurry that is prepared by mixing a particulate material comprising ground red mud, an alkaline activator, an aqueous solvent, and a SiO2 source material added to produce a geopolymer slurry with a Si/Al ratio of from 2 to 6. The method for well cementing includes pumping a geopolymer slurry into a location to be cemented and hardening the geopolymer slurry to form a cement.
Claims7
A composition for well cementing comprising a geopolymer slurry comprising a homogeneous mixture of:
- ground red mud, wherein the ground red mud comprises Al2O3 and SiO2 and has a fine particle size, wherein the fine particle size is characterized by 80% of the ground red mud having a particle size of 50 μm or less;
- an alkaline activator comprising sodium silicate with a molar ratio of SiO2 to Na2O of 3.4 to 1, wherein the alkaline activator has a pH of 12-13;
- an aqueous solvent in an amount of from 10% to 70% by weight of the ground red mud;
- and
- a SiO2 source material, present in an amount to produce a Si/Al ratio in the geopolymer slurry of from 2 to 6, wherein the SiO2 source material is selected from the group consisting of silica fume, cement, nanosilica, and fine sand having an average particle size of 150 μm or less, wherein the cement excludes ordinary portland cement;
- wherein the Al2O3 in the ground red mud, the SiO2 in the ground red mud, the alkaline activator, the aqueous solvent, and the SiO2 source material form a gel by a geopolymerization reaction, under reaction conditions comprising a temperature of 100° F. to 180° F. with a thickening time of 1 to 6 hours, wherein the geopolymerization reaction comprises a polycondensation reaction of mixed hydroxyl ions formed from dissolution of Al2O3 and SiO2 of the geopolymer slurry under alkaline conditions.
A method of cementing, the method comprising:
- pumping a geopolymer slurry into a location to be cemented,
- wherein the geopolymer slurry comprises a homogeneous mixture of:
- ground red mud, wherein the ground red mud comprises Al2O3 and SiO2 and has a fine particle size, wherein the fine particle size is characterized by 80% of the ground red mud having a particle size of 50 μm or less;
- an alkaline activator comprising sodium silicate with a molar ratio of SiO2 to Na2O of 3.4 to 1, wherein the alkaline activator has a pH of 12-13;
- an aqueous solvent in an amount of from 10% to 70% by weight of the ground red mud;
- and
- a SiO2 source material, present in an amount to produce a Si/Al ratio in the geopolymer slurry of from 2 to 6, wherein the SiO2 source material is selected from the group consisting of silica fume, cement, nanosilica, and fine sand having an average particle size of 150 μm or less, wherein the cement excludes ordinary portland cement;
- reacting the Al2O3 in the ground red mud, the SiO2 in the ground red mud, the alkaline activator, the aqueous solvent, and the SiO2 source material by a geopolymerization reaction to form a gel, under reaction conditions comprising a temperature of 100° F. to 180° F. with a thickening time of 1 to 6 hours, wherein the geopolymerization reaction comprises a polycondensation reaction of mixed hydroxyl ions formed from dissolution of Al2O3 and SiO2 of the geopolymer slurry under alkaline conditions;
- and
- hardening the gel to form a cement;
- wherein the location to be cemented is a well, a well bore, or a well bore annulus.
Dependencies are inferred from the claim text.