Method for decreasing permeability around a wellbore
US4721161A · kind A · utility
7Cited by
8References
24Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1986 |
| Grant date | Jan 26, 1988 |
| Priority date | — |
| Expiry date | Jun 30, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K8/887
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The permeability of an underground formation near a wellbore can be substantially decreased by the injection of one or more slugs of an aqueous solution containing an in situ forming gel of lignosulfonate and a monomer of acrylamide or acrylic acid, initiated by persulfate or hydroxylamine and a relatively small amount of a metal salt having a polyvalent cation. The gel can be formed in the formation by delaying the mixing of all of the gel components into the aqueous solution until just prior to injection or splitting up the components into two aqueous solutions so that they are not mixed until they are in the formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.