Lightweight cement slurry and method of use
First Claim
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1. A foamed hydraulic cement slurry comprising an aqueous, thixotropic slurry of hydraulic cement in which is dispersed, as discrete stable bubbles, a gas or mixture of gases and which comprises calcium sulfate hemihydrate in an amount sufficient to impart thixotropic properties to said slurry.
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Abstract
A foamed, thixotropic hydraulic cement slurry and method of using same in cementing subterranean voids. This lightweight cement slurry is particularly useful for cementing in oil or gas wellbores penetrating a weak underground formation which will be broken by cement slurries of ordinary density.
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23 Claims
- 1. A foamed hydraulic cement slurry comprising an aqueous, thixotropic slurry of hydraulic cement in which is dispersed, as discrete stable bubbles, a gas or mixture of gases and which comprises calcium sulfate hemihydrate in an amount sufficient to impart thixotropic properties to said slurry.
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8. A foamed, hydraulic cement slurry comprising an aqueous, thixotropic slurry of hydraulic cement, comprising Portland cement and comprising calcium sulfate hemihydrate in an amount sufficient to impart thixotropic properties to said slurry, in which slurry a gas or mixture of gases is dispersed as discrete, stable bubbles, wherein the parts of solids and parts of gas per 100 parts of water, range, from about 27 and 45, respectively, to about 100 and 220, respectively, by volume.
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22. A foamed, hydraulic cement slurry comprising an aqueous, thixotropic slurry of hydraulic cement, comprising Portland cement and calcium sulfate hemihydrate, in which slurry a gas or a mixture of gases is dispersed as discrete, stable bubbles, wherein about 10 parts to about 20 parts calcium sulfate hemihydrate are present per 100 parts Portland cement;
- about 27 to about 100 parts solids and about 45 parts to about 220 parts gas are present per 100 parts of water;
wherein the major portion of said bubbles have an average diameter of about 1 millimeter or less; and
wherein a surfactant is present in an amount of about 0.5 part to about 2 parts per 100 parts water;
all parts by volume. - View Dependent Claims (23)
- about 27 to about 100 parts solids and about 45 parts to about 220 parts gas are present per 100 parts of water;
Specification