Lightweight cement and method of cementing therewith
First Claim
1. In a process for cementing a bore hole intersecting a subterranean formation in which the cementing composition may be at an elevated temperature using an aqueous hydraulic cement slurry, the improvement of adding to the cement slurry to decrease its thermal conductivity, to decrease its density and to provide high strength at the elevated temperature, the components comprising a fine particulate crystalline silica having a particle size of less than about 10 mesh and a lightweight inorganic material which does not absorb a substantial quantity of water and which lowers the density of said slurry to about 8.5-13.0 pounds/gallon under well cementing conditions.
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Abstract
A low-density, high-strength cement composition useful in a high temperature environment, such as in thermal wells, which includes hydraulic cement, a siliceous material and a relatively low-density inorganic material.
232 Citations
38 Claims
- 1. In a process for cementing a bore hole intersecting a subterranean formation in which the cementing composition may be at an elevated temperature using an aqueous hydraulic cement slurry, the improvement of adding to the cement slurry to decrease its thermal conductivity, to decrease its density and to provide high strength at the elevated temperature, the components comprising a fine particulate crystalline silica having a particle size of less than about 10 mesh and a lightweight inorganic material which does not absorb a substantial quantity of water and which lowers the density of said slurry to about 8.5-13.0 pounds/gallon under well cementing conditions.
- 19. A high-strength, low density thermally stable hydraulic cement composition comprising an aqueous slurry of hydraulic cement containing fine particulate, crystalline silica having a particle size of less than about 10 mesh and a lightweight inorganic material which does not absorb a substantial quantity of water, which is compatible with the components of the cement slurry and which has a density which is less than 50 percent of the density of the particulate, crystalline silica wherein said lightweight material lowers the density of said slurry to about 8.5-13.0 pounds/gallon under well cementing conditions.
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34. A pumpable cement composition which contains portland cement, silica, lightweight sealed spheres of siliceous material, and water mixed to yield cement having a 24-hour compressive strength, after curing at 500°
- F. and 5600 psi, which exceeds 800 psi, a permeability less than 1 millidarcy, and a density of from 8.5 to 13 pounds/gallon under well cementing conditions.
- View Dependent Claims (35, 36)
- 37. In an aqueous hydraulic cement slurry, the improvement of adding to said slurry to produce a thermally stable cement which has low density and good early and ultimate compressive strength at high temperatures a quantity of sealed, impermeable hollow beads of siliceous material adequate to lower the density of the slurry to about 8.5-13.0 pounds/gallon under well cementing conditions wherein said beads do not undergo significant increase in density with increase in pressure.
Specification