High temperature cement system

• US 4,144,077 A
• Filed: 10/25/1977
• Issued: 03/13/1979
• Est. Priority Date: 06/28/1976
• Status: Expired due to Term

• Current Assignee: Union Oil Company of California (Chevron Corp.)
• Original Assignee: Union Oil Company of California (Chevron Corp.)
• Inventors: Gallus, Julius P.
• Primary Examiner(s): Poer, James
• Application Number:
  US05/844,642
• Time in Patent Office: 504 Days
• Field of Search: 106/97, 106/104, 166/291, 166/292, 166/293
• US Class Current: 106/669
• CPC Class Codes: C04B 14/022 Carbon
• CPC Class Codes: C04B 18/12 from quarries, mining or the like
• CPC Class Codes: C04B 18/125 Slate residues, e.g. colliery shale or oil shale or oil shale ash
• CPC Class Codes: C04B 2103/0028 according to API
• CPC Class Codes: C04B 2103/0088 Compounds chosen for their latent hydraulic characteristics, e.g. pozzuolanes
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 28/021 Ash cements, e.g. fly ash cements fly ash as filler C04B18/08; Cements based on incineration residues, e.g. alkali-activated slags from waste incineration alkali-activated combustion residues as such C04B7/243; mixtures of the lime-pozzuolane type C04B28/18; Kiln dust cements
• CPC Class Codes: C04B 28/06 Aluminous cements monolithic refractories or refractory mortars C04B35/66
• CPC Class Codes: C04B 7/02 Portland cement
• CPC Class Codes: C09K 8/467 containing additives for specific purposes
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

A high temperature cement system including a carbon-containing, low volatile material additive admixed with cement in proportions sufficient to provide a fixed carbon content of at least 0.02 weight percent. Additives include anthracite, calcined coke, uncalcined coke, burned oil shale and raw oil shale.

Claims

1. A cement system which upon hydration and curing forms a hardened cement mass, said cement system consisting essentially of cement and an effective amount, less than 20 weight percent of said cement system, of a carbon-containing cement additive selected from the group consisting of anthracite, calcined coke, uncalcined coke, raw oil shale and burned oil shale, said cement additive having between about 1 and about 15 weight percent volatile material, said amount being effective to impart to said cement mass an ultimate compressive strength of at least about 1000 p.s.i. and an ultimate permeability less than about 1 millidarcy when exposed to high temperatures.

2. The cement system of claim 1 wherein said cement additive is present in an amount sufficient to provide at least about 0.02 weight percent carbon in said cement system.

3. The cement system of claim 1 wherein said cement additive has a volatile material content of between about 2 and about 10 eight percent.

4. The cement system of claim 1 wherein said cement additive comprises at least about 5 weight percent of said cement system.

5. The cement system of claim 4 wherein said cement additive comprises between about 6 and about 15 weight percent of said cement system.

6. The cement system of claim 1 wherein said cement is selected from the group consisting of Portland cement, pozzolan cement, high alumina cement and mixtures thereof.

7. The cement system of claim 1 wherein said cement is an oil well cement selected from the group consisting of API Class G cement and API Class J cement.

8. The cement system of claim 1 admixed with a water-containing liquid vehicle to form a slurry of pumpable consistency.

9. The cement system of claim 8 wherein said liquid vehicle is selected from the group consisting of water and mixtures of water and a liquid hydrocarbon.

10. A cement system consisting essentially of oil well cement and from about 6 to about weight percent of a carbon-containing cement additive selected from the group consisting of anthracite, calcined coke, uncalcined coke, raw oil shale and burned oil shale, said cement additive having a volatile material content of between about 2 and about 10 weight percent.

11. The cement system of claim 10 wherein said oil well cement is selected from the group consisting of Portland cement, pozzolan cement, high alumina cement and mixtures thereof.

12. The cement system of claim 10 admixed with a water-containing liquid vehicle to form a slurry of pumpable consistency.

13. The cement system of claim 10 comprising from about 84 to about 93 weight percent of said oil well cement, from about 6 to about 15 weight percent of said cement additive and about 1 weight percent of a water loss inhibitor.

14. A cement system consisting essentially of an oil well cement selected from the group consisting of API Class G cement and API Class J cement, and from about 6 to about 15 weight percent of a carbon-containing cement additive selected from the group consisting of anthracite, calcined coke, uncalcined coke, raw oil shale and burned oil shale, said cement additive having a volatile material content of between about 2 and about 10 weight percent.

15. A hardened cement mass having improved resistance to degradation of its ultimate permeability and compressive strength when exposed to high temperatures, which cement mass is prepared by the method comprising:

forming a hardenable slurry consisting essentially of a cement system and a water-containing liquid vehicle, said cement system consisting essentially of cement and from about 6 to about 15 weight percent of a carbon-containing cement additive selected from the group consisting of anthracite, calcined coke, uncalcined coke, raw oil shale and burned oil shale, said cement additive having a volatile material content of between about 1 and about 15 weight percent; and

curing said hardenable slurry to form said cement mass.

16. Th cement mass of claim 15 wherein said cement is an oil well cement selected from the group consisting of API Clas G cement and API Class J cement.

17. The cement mass of claim 15 wherein said cement additive has a volatile material content between about 2 and about 10 weight percent.

18. The cement mass of claim 15 wherein said hardenable slurry is cured under high temperature and pressure conditions.

19. The cement mass of claim 15 wherein said hardenable slurry is introduced through a bore hole into a confined space in fluid communication with the bore hole and is therein allowed to cure to form said cement mass.

20. The cement mass of claim 19 wherein said hardenable slurry is cured under high temperature and pressure conditions.

21. The cement mass of claim 19 wherein said confined space is an annular space between the walls of the bore hole and a casing or liner disposed in the bore hole.