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US 4,200,153 AGranted
Method for cementing high temperature wells
AssigneeUnion Oil Company of California
InventorJulius P. Gallus
Life of this patent
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Abstract
A cement system including minor amounts of a carbon black cement additive admixed with cement is used to cement high temperature wells.
Claims12
A method for placing a hardened cement mass having improved resistance to degradation of its ultimate permeability and compressive strength when exposed to high temperatures in a confined space in fluid communication with a well, comprising:
- forming a hardenable slurry comprised of a cement system and a water-containing liquid vehicle, said cement system comprising (1) a cement selected from the group consisting of Portland cement, pozzolan cement, high alumina cement and mixtures thereof, and (2) a carbon black cement additive which is present in an amount, between about 0.01 and about 1 weight percent of said cement system, effective to improve the resistance to degradation of the ultimate permeability and compressive strength of said cement mass;
- introducing said hardenable slurry through said well and into said confined space;
- and
- allowing said hardenable slurry to set and harden under the high temperature and pressure conditions in said well to thereby form said cement mass.
1 more element
A method for placing a hardened cement mass having improved resistance to degradation of its ultimate permeability and compressive strength when exposed to high temperatures in a confined space in fluid communication with a well, comprising:
- forming a hardenable slurry comprised of a cement system and a water-containing liquid vehicle, said cement system comprising
- (1) an oil well cement selected from the group consisting of API Class G cement and API Class J cement, and
- (2) a carbon black cement additive having a fixed carbon content between about 95 and about 99.5 weight percent, said cement additive being present in an amount, between about 0.1 and about 0.5 weight percent of said cement system, effective to impart to said cement mass an ultimate compressive strength of at least about 1,000 p.s.i. and an ultimate permeability less than about one millidarcy;
- and
- introducing said hardenable slurry through said well and into said confined space;
- and
- allowing said hardenable slurry to set and harden under the high temperature and pressure conditions in said well to thereby form said cement mass.
4 more elements
Dependencies are inferred from the claim text.