High temperature set retarded well cement compositions and methods
US4997487A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1990 |
| Grant date | Mar 5, 1991 |
| Priority date | — |
| Expiry date | Mar 7, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2111/00146
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Set retarded cement compositions which are substantially non-thinning at high temperatures are provided. The compositions are comprised of hydraulic cement, sufficient water to form a pumpable slurry, a set retarder and a galactomannan gum which has been treated with a hydrophobing agent whereby the hydration rate of the gum is retarded at temperatures below about 120.degree. F. and at pH levels above about 10. The delayed hydration of the treated gum offsets the thinning of the cement compositions at temperatures above about 120.degree. F. Methods of cementing subterranean zones penetrated by well bores utilizing the cement compositions are also provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.