Cement compositions and methods for high temperature wells containing carbon dioxide
AssigneeHalliburton Energy Services, Inc.
InventorsLance E. Brothers, Susan M. Turkett, Barry B. Ekstrand, D. Chad Brenneis, Jerry D. Childs
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Abstract
The present invention provides light weight high temperature well cement compositions and methods. The compositions are basically comprised of calcium aluminate, ASTM class F fly ash and water.
Claims26
An improved cement composition useful for cementing high temperature wells containing carbon dioxide comprising:
- calcium aluminate present in an amount of about 15% to about 45% by weight of said composition;
- fly ash present in an amount of about 25% to about 45% by weight of said composition;
- sodium polyphosphate present in an amount in the range of from about 5% to about 13% by weight of the composition;
- a set retarder for lengthening the time in which said composition starts to thicken and set whereby said composition is capable of being pumped into wells having bottom hole temperatures above about 125° F., said set retarder being present in an amount in the range of from about 0.5% to about 2% by weight of said composition;
- and
- sufficient water to form a pumpable slurry.
An improved cement composition useful for cementing high temperature wells containing carbon dioxide comprising:
- calcium aluminate present in an amount of about 15% to about 45% by weight of said composition;
- fly ash present in an amount of about 25% to about 45% by weight of said composition;
- sodium polyphosphate present in an amount of about 5% to about 20% by weight of the composition;
- a set retarder for lengthening the time in which said composition starts to thicken and set whereby said composition is capable of being pumped into wells having bottom hole temperatures above about 125° F., said set retarder being present in an amount in the range of from about 0.5% to about 2% by weight of said composition;
- and
- sufficient water to form a pumpable slurry.
A method of cementing a subterranean zone comprising the steps of:
- forming a well cement composition comprising:
- calcium aluminate present in an amount of about 15% to about 45% by weight of said composition,
- fly ash present in an amount of about 25% to about 45% by weight of said composition,
- sodium polyphosphate present in an amount in the range of from about 5% to about 20% by weight of the composition, and
- sufficient water to form a pumpable slurry;
- pumping said cement composition into said subterranean zone;
- and
- allowing said cement composition to set into a hard impermeable mass therein.
A method of cementing a subterranean zone comprising the steps of:
- forming a well cement composition comprising:
- calcium aluminate present in an amount of about 15% to about 45% by weight of said composition,
- ASTM class F fly ash present in an amount of about 25% to about 45% by weight of said composition,
- sodium polyphosphate present in an amount of about 5% to about 20% by weight of the composition,
- a set retarder selected from the group consisting of citric acid, gluconic acid and tartaric acid present in an amount of about 0.5% to about 2% by weight of said composition, and
- sufficient water to form a pumpable slurry;
- pumping said cement composition into said subterranean zone;
- and
- allowing said cement composition to set into a hard impermeable mass therein.
Dependencies are inferred from the claim text.