Method for control of gas migration in well cementing
US5339903A · kind A · utility
73Cited by
9References
5Claims
0Family size
Assignee
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Key dates
| Filing date | Nov 12, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Nov 12, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2103/46
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of cementing a wellbore which penetrates a subsurface gas-containing formation is provided whereby gas migration is reduced. The method features the use of an additive consisting of a tannin backbone having grafted thereto at least two different vinylamide derivatives. The additive causes the cement slurry employed in the method to exhibit a Zero Gel Time of greater than about one hour, a Transition Time of less than about one hour and controls fluid loss from the slurry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.