Claims
- 1. A cement composition comprising:a hydraulic cement; water present in an amount sufficient to form a pumpable slurry; and an environmentally acceptable fluid loss control additive comprising hydroxyethylcellulose having a reduced molecular weight in the range of from about 30,000 to about 90,000 ethoxylated in an amount in the range of from about 1 to about 4 moles of ethylene oxide per anhydroglucose unit.
- 2. The composition of claim 1 wherein said hydraulic cement is Portland cement.
- 3. The composition of claim 1 wherein said hydraulic cement is Portland API Class G cement.
- 4. The composition of claim 1 wherein said water is fresh water or salt water.
- 5. The composition of claim 1 wherein said water is present in an amount in the range of from about 25% to about 100% by weight of cement in said composition.
- 6. The composition of claim 1 wherein said hydroxyethylcellulose has an average molecular weight of about 60,000.
- 7. The composition of claim 1 wherein said hydroxyethylcellulose is ethoxylated in the range of from about 2.2 to about 2.7 moles of ethylene oxide per anhydroglucose unit.
- 8. The composition of claim 1 wherein said hydroxyethylcellulose is ethoxylated in an average amount of about 2.5 moles of ethylene oxide per anhydroglucose unit.
- 9. The composition of claim 1 wherein the additive is stable and effectively controls fluid loss from cement compositions at temperatures above 230° F. to at least about 260° F.
- 10. The composition of claim 1 wherein the additive can be utilized in contact with salt water containing salt up to 37.2% by weight without losing effectiveness.
- 11. The composition of claim 1 wherein the additive can be dissolved in water up to about 12.5% by weight of the resulting solution.
- 12. The composition of claim 1 further comprising a temperature stability increasing agent.
- 13. The composition of claim 12 wherein said temperature stability increasing agent is selected from the group consisting of synthetic hectorite, magnesium oxide and sodium thiosulfate.
- 14. The composition of claim 12 wherein said temperature stability increasing agent is magnesium oxide.
- 15. The composition of claim 12 wherein said temperature stability increasing agent is present in said additive in an amount in the range of from about 50% to about 500% by weight of said ethoxylated hydroxyethylcellulose.
- 16. The composition of claim 12 wherein said temperature stability increasing agent is present in an amount of about 100% by weight of said ethoxylated hydroxyethylcellulose.
- 17. A cement composition comprising:a hydraulic cement; water present in an amount sufficient to form a pumpable slurry; an improved environmentally acceptable well cement fluid loss control additive comprising hydroxyethylcellulose having a reduced molecular weight in the range of from about 30,000 to about 90,000 and being ethoxylated in an amount in the range of from about 1 to about 4 moles of ethylene oxide per anhydroglucose unit; and a temperature stability increasing agent present in said additive in an amount in the range of from about 50% to about 500% by weight of said ethoxylated hydroxyethylcellulose and selected from the group consisting of synthetic hectorite, magnesium oxide and sodium thiosulfate.
- 18. The composition of claim 17 wherein said hydroxyethylcellulose has an average molecular weight of about 60,000.
- 19. The composition of claim 17 wherein said hydroxyethylcellulose is ethoxylated in an average amount of about 2.5 moles of ethylene oxide per anhydroglucose unit.
- 20. The composition of claim 17 wherein said temperature stability increasing agent is magnesium oxide.
- 21. The composition of claim 17 wherein said temperature stability increasing agent is present in an amount of about 100% by weight of said ethoxylated hydroxyethylcellulose.
- 22. A cement composition comprising:a hydraulic cement; water present in an amount sufficient to form a pumpable slurry; an improved environmentally acceptable well cement fluid loss control additive comprising hydroxyethylcellulose having a reduced molecular weight of about 60,000 and being ethoxylated in an amount in the range of from about 2.5 moles of ethylene oxide per anhydroglucose unit; and a temperature stability increasing agent present in said additive in an amount of about 100% by weight of said ethoxylated hydroxyethylcellulose and wherein said temperature stability increasing agent is magnesium oxide.
CROSS-REFERENCE TO RELATED APPLICATION
This is a divisional of application Ser. No. 09/732,861 filed on Dec. 8, 2000, now pending.
US Referenced Citations (27)