Development of geopolymer cements utilizing red mud for primary well cementing applications
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 SiO 2 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.
1 . A composition for well cementing comprising a geopolymer slurry comprising a homogeneous mixture of:
ground red mud, wherein the ground red mud comprises Al 2 O 3 and SiO 2 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 SiO 2 to Na 2 O 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 SiO 2 source material, present in an amount to produce a Si/Al ratio in the geopolymer slurry of from 2 to 6, wherein the SiO 2 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 Al 2 O 3 in the ground red mud, the SiO 2 in the ground red mud, the alkaline activator, the aqueous solvent, and the SiO 2 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 Al 2 O 3 and SiO 2 of the geopolymer slurry under alkaline conditions.
2 . The composition of claim 1 , wherein the aqueous solvent comprises one or more waters selected from the group consisting of deionized water, tap water, fresh water, municipal water, formation water, produced water, well water, filtered water, distilled water, sea water, salt water, natural brine, synthetic brine, or a combination thereof.
3 . The composition of claim 1 , further comprising an additive selected from the group consisting of accelerators, retarders, extenders, weighting agents, fluid loss control agents, lost circulation control agents, surfactants, antifoaming agents, elastomers, fibers, or combinations thereof.
4 . 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 Al 2 O 3 and SiO 2 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 SiO 2 to Na 2 O 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 SiO 2 source material, present in an amount to produce a Si/Al ratio in the geopolymer slurry of from 2 to 6, wherein the SiO 2 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 Al 2 O 3 in the ground red mud, the SiO 2 in the ground red mud, the alkaline activator, the aqueous solvent, and the SiO 2 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 Al 2 O 3 and SiO 2 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.
5 . The method of claim 4 , wherein hardening the gel comprises exposing the gel to conditions of the location to be cemented.
6 . The method of claim 4 , wherein the aqueous solvent comprises one or more waters selected from the group consisting of deionized water, tap water, fresh water, municipal water, formation water, produced water, well water, filtered water, distilled water, sea water, salt water, natural brine, synthetic brine, or a combination thereof.
7 . The method of claim 4 , wherein the geopolymer slurry further comprises an additive selected from the group consisting of accelerators, retarders, extenders, weighting agents, fluid loss control agents, lost circulation control agents, surfactants, antifoaming agents, elastomers, fibers, or combinations thereof.