Composition for controlling the set time of cement
OwnerRobert Lee Dillenbeck, IIIinventor
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Abstract
An oil and gas well cementing composition and method are shown utilizing hydraulic cement, water a cement hydration retarder and an additive which is effective over a selected time period degrade the retarder. The additive is a controlled release oxidizer which releases nascent oxygen over time to gradually oxidize the cement hydration retarder, thereby providing a single cement slurry design for cementing pipes for oil and gas wells where wide temperature differentials exist between the two ends of the pipe.
Claims21
A cementing composition for oil and gas wells, comprising:
- hydraulic cement;
- an organic cement hydration retarder;
- an oxidative additive present in an amount sufficient to gradually destroy the retarder by gradually oxidizing the retarder over a period of time;
- and
- water present in an amount sufficient to produce a pumpable slurry.
A cementing composition for use in a well bore having a top and a bottom, comprising;
- hydraulic cement;
- water present in an amount sufficient to produce a pumpable slurry;
- a cement hydration retarder present in an amount sufficient to maintain the pumpable slurry for about 2 hours at temperatures common at the bottom of the well bore;
- an oxidative additive present in a sufficient amount to destroy the cement hydration retarder over an amount of time sufficient to allow the cement composition to develop a compressive strength of about 200 psi in about 12 hours at temperatures common at the top of a well bore.
A cementing composition for use in a well bore having a top and a bottom, comprising:
- a hydraulic cement;
- water present in an amount sufficient to produce a pumpable slurry;
- a cement hydration retarder comprising lignosulfonate, the cement hydration retarder present in an amount sufficient to maintain a pumpable slurry for about 2 hours at temperatures common at the bottom of the well bore;
- an oxidative additive comprising calcium peroxide, the oxidative additive present in an amount sufficient to destroy the cement hydration retarder over an amount of time sufficient to allow the cement composition to develop a compressive strength of about 200 psi in about 12 hours at temperatures common at the top of a well bore.
Dependencies are inferred from the claim text.