Cement slurries for well bores
AssigneeBJ Services Company
InventorsRoderick B. Pernites, Felipe Padilla Florencia, Jordan Lee Clark, Angel Gonzalez
Life of this patent
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Abstract
Cement slurries are provided for use in cementing oil and gas wells. The cement slurry comprises API Class C or Class H Portland cement and a pozzolan selected from the group consisting of pumice and mixtures of pumice and fly ash. Pumice is present in the mixtures in amounts at least about 40 wt % of the pozzolan. The weight ratio of the pozzolan to the cement is from about 35:65 to about 70:30. The novel cement slurries preferably will not comprise any additional lime, including hydrated lime, or other activators.
Claims25
A settable cementitious slurry for use in a subterranean well, said cement slurry comprising cementitious components, said cementitious components consisting essentially of:
- (a) API Class C or Class H Portland cement;
- and
- (b) a pozzolan selected from the group consisting of pumice and mixtures of pumice and fly ash, wherein pumice is at least about 40 wt % of said pozzolan;
- (c) wherein the weight ratio of said pozzolan to said cement is from about 35:65 to about 70:30;
- and
- (d) wherein said pozzolan has an average particle size less than about 20 μm.
Dependencies are inferred from the claim text.