Programmed gelation of polymers for oil reservoir permeability control
US4606407A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 29, 1984 |
| Grant date | Aug 19, 1986 |
| Priority date | — |
| Expiry date | Nov 29, 2004 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K8/512
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Polymers used for the control of permeability in stratified subterranean formations are gelled in a controlled manner by the use of rapid and delayed gelling agents. The polymer is first gelled lightly by the use of a rapid gelling agent which partly cross-links the polymer to produce a viscous solution which will selectively enter only the more permeable regions of the formation but can still be readily injected. A delayed cross-linking agent completes the cross-linking process after the polymer has been selectively emplaced to form a firm, full strength gel. Suitable rapid cross-linking agents may be formed by the reaction of alkalies and chromic salts at specified ratios or by the redox reduction of chromium from its higher oxidation states under certain specified conditions. Delayed cross-linking agents are exemplified by chromic salts. Polymers which may be used include polyacrylamides and polysaccharide biopolymers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.