Lightweight hollow particles for use in cementing
AssigneeBaker Hughes Incorporated
InventorsThomas J. Pisklak, Elizabeth G. Morillo, Qi Qu
Life of this patent
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Abstract
A lightweight composite having an activated surface contains a lightweight hollow core particle having cement grains which may be adhered to the hollow core or embedded in the surface of the hollow core. The hollow core particle may be prepared from calcium carbonate and a mixture of clay, such as bentonite, and a glassy inorganic material, such as glass spheres, glass beads, glass bubbles, borosilicate glass and fiberglass.
Claims22
A composite comprising a lightweight hollow core and cement grains, wherein the lightweight hollow core is formed from calcium carbonate, clay and an inorganic material and further wherein the cement grains are adhered to the surface of the lightweight hollow core, embedded in the surface of the lightweight hollow core or are both adhered to the surface of the lightweight hollow core and embedded in the surface of the lightweight hollow core.
A lightweight hollow particle prepared by heating a precursor powder comprising (i) calcium carbonate and (ii) a mixture of bentonite and a glassy inorganic material comprising borosilicate glass to a temperature between from about 650° C. to about 850° C. for a time sufficient to decompose the calcium carbonate and at least partially melt the glassy inorganic material, wherein gases evolved during the heating expand the semi-molten glassy inorganic material outwardly to render the lightweight hollow sphere.
A method of preparing a lightweight cement particle comprising:
- (a) mixing calcium carbonate and a glassy inorganic material comprising bentonite, inorganic glass and, optionally, a binder;
- (b) heating the mixture to the softening temperature of the inorganic glass to produce a lightweight hollow core particle;
- (c) applying a coating to at least a partial surface of the lightweight core particle;
- (d) applying cement grains to the coated lightweight core particle;
- and
- (e) hardening the coating.
A method of preparing a lightweight cement particle comprising:
- (a) mixing calcium carbonate and a mixture of an inorganic material and bentonite and forming lightweight particles;
- (b) adding cement powder to the formed lightweight particles;
- (c) drying the product of step (b);
- (d) heating the dried product of step (c) to the glass transition temperature of the inorganic material;
- and
- (e) cooling the product of step (d).
Dependencies are inferred from the claim text.