Geopolymer cement for use in subterranean operations

1. A method comprising:

first forming a set-delayed geopolymer cement composition comprising a geopolymer material and a set retarder, wherein the geopolymer material comprises an aluminosilicate source, a metal silicate source, an alkali activator, and water;

then mixing a slurry activator into the set-delayed geopolymer cement composition to activate the set-delayed geopolymer cement composition, wherein the slurry activator comprises water and hydrated lime;

introducing the set-delayed geopolymer cement composition into at least a portion of a subterranean formation; and

allowing the set-delayed geopolymer cement composition to at least partially set in the subterranean formation.

2. The method of claim 1 , wherein the step of mixing the slurry activator into the set-delayed geopolymer cement composition further comprises introducing the slurry activator into the portion of the subterranean formation substantially simultaneously with introducing the set-delayed geopolymer cement composition into the portion of the subterranean formation.

3. The method of claim 1 , wherein the slurry activator further comprises a dispersant.

4. The method of claim 1 , wherein the geopolymer material and the hydrated lime are present in a weight ratio of geopolymer material to hydrated lime of about 38:1 to about 48:1.

5. The method of claim 1 , wherein the step of mixing the slurry activator into the set-delayed geopolymer cement composition further comprises introducing the slurry activator into the portion of the subterranean formation after introducing the set-delayed geopolymer cement composition into at least the portion of the subterranean formation.

6. The method of claim 1 , wherein the aluminosilicate source is selected from the group consisting of a metakaolin clay, a calcined clay, a partially calcined clay, a kaolinite clay, a lateritic clay, an illite clay, a volcanic rock, a mine tailing, blast furnace slag, coal fly ash, any derivative thereof, and any combination thereof.

7. The method of claim 1 , wherein the alkali activator is a metal hydroxide.

8. The method of claim 1 , wherein the set-delayed geopolymer cement composition remains in a pumpable fluid state for at least about 1 day or more prior to mixing the slurry activator into the set-delayed geopolymer cement composition.

9. The method of claim 1 , wherein the set-delayed geopolymer cement composition further comprises at least one additive selected from the group consisting of a weighting agent, a gas-generating additive, a lost-circulation material, and any combination thereof.

10. The method of claim 1 , wherein the set-delayed geopolymer cement composition sets after mixing the slurry activator into the set-delayed geopolymer cement composition to develop a 24-hour compressive strength of at least about 50 psi as measured using a destructive crush test at 140° F. (60° C.).

11. The method of claim 1 , wherein the set-delayed geopolymer cement composition is introduced into an annulus between a wall of a well bore and a conduit disposed in the well bore.

12. A method comprising:

storing a set-delayed geopolymer cement composition for a period of about 1 day or longer, wherein the set-delayed geopolymer cement composition comprises a set retarder and a geopolymer material comprising an aluminosilicate source, a metal silicate source, a metal hydroxide, and water;

activating the set-delayed geopolymer cement composition after storing by adding slurry activator to the set-delayed geopolymer cement composition, wherein the slurry activator comprises water and hydrated lime;

introducing the set-delayed geopolymer cement composition into at least a portion of a subterranean formation; and

allowing the set-delayed geopolymer cement composition to set in the subterranean formation.

13. The method of claim 12 , wherein the step of introducing the set-delayed geopolymer cement composition into at least the portion of the subterranean formation comprises using a pump to introduce the set-delayed geopolymer cement composition into an annulus between a wall of a well bore and a conduit disposed in the well bore.

14. The method of claim 12 , wherein the aluminosilicate source is a metakaolin clay, the metal silicate source is a sodium silicate, and the metal hydroxide is sodium hydroxide.

15. A method comprising:

first forming a set-delayed geopolymer cement composition comprising a geopolymer material and a set retarder, wherein the geopolymer material comprises an aluminosilicate source, a metal silicate source, an alkali activator, and water;

then mixing a slurry activator into the set-delayed geopolymer cement composition to activate the set-delayed geopolymer cement composition, wherein the slurry activator comprises water and Portland cement;

introducing the set-delayed geopolymer cement composition into at least a portion of a subterranean formation; and

allowing the set-delayed geopolymer cement composition to at least partially set in the subterranean formation.

16. The method of claim 15 , wherein the step of mixing the slurry activator into the set-delayed geopolymer cement composition further comprises introducing the slurry activator into the portion of the subterranean formation substantially simultaneously with introducing the set-delayed geopolymer cement composition into the portion of the subterranean formation.

17. The method of claim 15 , wherein the step of mixing the slurry activator into the set-delayed geopolymer cement composition further comprises introducing the slurry activator into the portion of the subterranean formation after introducing the set-delayed geopolymer cement composition into at least the portion of the subterranean formation.

18. The method of claim 15 , wherein the aluminosilicate source is selected from the group consisting of a metakaolin clay, a calcined clay, a partially calcined clay, a kaolinite clay, a lateritic clay, an illite clay, a volcanic rock, a mine tailing, blast furnace slag, coal fly ash, any derivative thereof, and any combination thereof.

19. The method of claim 15 , wherein the set-delayed geopolymer cement composition remains in a pumpable fluid state for at least about 1 day or more prior to mixing the slurry activator into the set-delayed geopolymer cement composition.

20. The method of claim 15 , wherein the set-delayed geopolymer cement composition sets after mixing the slurry activator into the set-delayed geopolymer cement composition to develop a 24-hour compressive strength of at least about 50 psi as measured using a destructive crush test at 140° F. (60° C.).