Method for controlling the set time of cement
AssigneeBJ Services Company
InventorRobert L. Dillenbeck, III
Life of this patent
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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 to 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.
Claims17
A method of cementing an oil and gas well, the method comprising the steps of:
- forming a cementing slurry by combining dry hydraulic cement, water in a sufficient amount to produce a pumpable slurry, a cement hydration retarder and an additive comprising a controlled release oxidizer which is effective to slowly release nascent oxygen over a selected period of time;
- pumping the cementing slurry to a desired location within the well bore;
- and
- allowing the cementing slurry to harden to a solid mass, the controlled release oxidizer serving to gradually oxidize the cement hydration retarder over the selected period of time.
A method of cementing a pipe having opposing pipe ends within a well bore of an oil and gas well where a large temperature differential exists in the well bore adjacent the opposing pipe ends, the method comprising the steps of:
- forming a cementing slurry by combining dry hydraulic cement, water in a sufficient amount to produce a pumpable slurry, a cement hydration retarder and an additive comprising a controlled release oxidizer which is effective to slowly release nascent oxygen over a selected period of time;
- pumping the cementing slurry within an annular area created between the pipe and the surrounding well bore;
- and
- allowing the cementing slurry to harden to a solid mass, the controlled release oxidizer serving to gradually oxidize the cement hydration retarder over the selected period of time, whereby destruction of the retarder serves to accelerate the setting process of the cement.
Dependencies are inferred from the claim text.