Cement slurries for well bores
First Claim
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1. 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 μ
m.
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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.
259 Citations
25 Claims
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1. A settable cementitious slurry for use in a subterranean well, said cement slurry comprising cementitious components, said cementitious components consisting essentially of:
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(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 μ
m. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification